PanoTools.org Wiki - User contributions [en]

DSLR spherical resolution

2009-08-16T22:14:36Z

Zbooy: /* Degree/mm */ typo

{{Glossary|What [[spherical]] panorama resolution can I obtain from a certain [[fisheyes|fisheye]]/camera combination.}}
==Intro==
In general photography megapixels are more or less synonymous to resulting image resolution. Panorama photography is a bit different, especially spherical panoramas. Here the sensor pixel density is more important than the sensor pixel count.

==The Problem==
Digital Single Lens Reflex (DSLR) cameras exist in three major groups:
* With FourThirds sensor (crop factor 2.0)
* With an APS-C type sensor (crop factor 1.5 or 1.6)
* With a sensor of the full 35mm film size (crop factor 1.0)

In each size category there are several cameras with different sensor resolutions. And there are several lenses that can be attached to cameras with different sensor sizes. To have the effects of different lenses comparable the concept of a 35mm equivalent focal length has been established - the real focal length multiplied with the crop factor gives the same [[Field of View]] like for a 35mm film camera.

However, this is not possible for [[fisheyes|fisheye]] lenses, since the [[Focal Length]] does not correspond linearly to the [[Field of View]]. One has to look at the degree/mm ratio and absolute pixel density instead.

==Degree/mm==
In the [[Fisheye Projection]] an angular distance from the optical axis maps to a linear distance on the sensor. The mapping is determined by the focal length (the following numbers are approximations, since real fisheyes almost never resemble the ideal fisheye mapping):

* 5.6mm focal length 11.4°/mm
* 8mm focal length 7.2°/mm
* 10.5mm focal length 5.5°/mm
* 16mm focal length 3.6°/mm

== Pixel density ==
To deduce the pixel resolution obtainable by a certain sensor/lens combination we should know the density in pixels/mm of the respective sensor. The pixel density can be calculated roughly from the Megapixels (better would be actual pixel size) and the sensor size. For the three major groups and some typical Megapixel sizes:

FourThirds with 13.5mm short side
Megapixel 6 8 10 12
Short side px 2121 2450 2739 3024
px/mm 157 181 203 232

APS-C with 16mm short side
Megapixel 6 8 10 12
Short side px 2000 2309 2582 2828
px/mm 125 144 161 177

Full size with 24mm short side
Megapixel 6 8 10 12 16 21
Short side px 2000 2309 2582 2828 3266 3742
px/mm 83 96 108 118 136 156

== Pano sizes ==
From the above values we can easily calculate some sample panorama resolutions. The table gives some rounded values for the maximum pixel size of an equirectangular:

FourThirds MP - - - - 6 8 10 12
APS-C MP - - 6 8 10 12 - -
Full size MP 6 8 12 16 21 - - -
pixel/mm 80 100 120 140 160 180 200 230
f=5.6mm size 2520 3150 3780 4420 5050 5680 6300 7260
f=8mm size 4000 5000 6000 7000 8000 9000 10000 11500
f=10.5mm size 5200 6500 7900 9200 10500 11800 13100 15000
f=16mm size 8000 10000 12000 14000 16000 18000 20000 23000

The formula for an exact calculation is <math> \frac {pixel/mm} {degree/mm} *360 </math>

--[[User:Erik Krause|Erik Krause]] 22:11, 21 August 2007 (CEST)
[[Category:Tutorial:Nice to know]]
[[Category:Glossary]]

Extract and insert rectilinear views

2007-03-21T18:07:00Z

Zbooy: typo

== Intro ==
One of the most problematic points when shooting spherical panoramas is the view straight down also called the nadir view. Either the tripod is visible or there may be alignment or color mismatches if shooting handheld.

Unfortunately neither the nadir nor the zenith (straight above) area can be edited directly in the [[equirectangular]] image since it is very distorted. For this task we need to extract a partial view - best in [[Rectilinear Projection]].

== Warning ==
Important! For all transformations that use non-overlapping images like assembling cube faces to an [[equirectangular]] image the 'Fast transform' option should be disabled. As a default 'Fast transform' is disabled for the [[Panorama Tools Plugins]] and for [[PTEditor]]. However, it is enabled by default for some of the GUIs ([[PTGui]] f.e.)

Fast Transform can cause the loss of some pixels in the corners of an [[Rectilinear Projection|rectilinear]] image which will be visible as small triangular black holes in the result image. More on 'Fast Transform' on [http://www.fsoft.it/panorama/pano12.htm Fulvio Senore's page].

PTGui 5 has a new internal stitcher which causes a similar effect even if Fast Transform is switched off. Don't use PTGui 5 internal stitcher to assemble cubefaces! Choose "Panotools Stitcher" (PTStitcher) instead.

== Possibilities ==
There are basically three possibilities to extract partial [[Rectilinear Projection|rectilinear]] views:
* [[PTEditor]]
* [[Panorama Tools Plugins]]
* [[PTStitcher]] or [[nona]] used directly or indirectly by script or batch file, GUI or [[PanoCube]] Plus

=== PTEditor ===
[[PTEditor]] is a [[Java]] application provided with the standard [[Panorama Tools]] distribution. It should run on any OS where Java and the panotools runtime (the [[pano12]] library) are installed. There is a nice tutorial on [[How to use PTEditor]]. This is the most convenient way to extract and insert any arbitrary [[Rectilinear Projection|rectilinear]] view. The disadvantage is that it doesn't save 16 bit images.

=== Panotools plugins ===
The [[Photoshop]] and [[Gimp]] compatible [[Panorama Tools Plugins]] are part of the standard Panotools distribution as well. There is an upgraded version available from [http://epaperpress.com/ptplugins/index.html Thomas Niemann] that corrects some bugs and works for 16 bit.

The plugins contain the [[Panorama Tools Plugins#Adjust|Adjust]] filter, which is capable of extracting and inserting any view in almost any projection. Any data (pan/tilt angle, size of view etc.) has to be inserted manually. Yaw, roll and pitch value have to be calculated or estimated which makes the usage a bit inconvenient.

However, extracting and inserting [[Zenith]] or [[Nadir]] is straightforward and relatively easy. [[Helmut Dersch]] has outlined the basic workflow in [http://www.path.unimelb.edu.au/~dersch/panorectilinear/panorectilinear.html Extracting Rectilinear Images from Panoramas]. You need to do the following:

==== Extracting ====
* Load the [[Equirectangular]] image in [[Photoshop]] (or any plugins compatible image editor).
* Choose 'Adjust' or 'PTAdjust' from the Filter menu.
* Press the small 'Prefs' button in the upper right corner.
* In the following dialog uncheck option (a) and check options (b) and (c) (see [[Panorama Tools Plugins#Preferences|plugins description for details]])
* confirm with 'Ok'
* check 'Extract', check 'Use Options' and press 'Set'
* In the following dialog there is an upper part called 'Image:' and a lower one called 'Panorama'
* In the 'Image' section:
** Set HFOV 90 for a cube face (or any other Field of View to your need).
** Choose 'Width' and 'Height' appr. 1/3 of the source image width in order to not degrade image because of too low resolution.
** Choose 'Format: Rectilinear'
** Set 'Yaw' and 'Roll' to 0.0
** Set 'Pitch' to -90 for [[Nadir]] or 90 for [[Zenith]]
* In the 'Panorama' section:
** Set HFOV to 360 for a full sphere.
** Leave 'Width' and 'Height' empty (will be read from the image)
** Check 'Save to Buffer' if you want to merge the result into your pano later.
** Choose Format: PSphere (which means [[Equirectangular]])
** Uncheck 'Load Buffer' to avoid loading of previously saved images.
* Press 'Ok' twice to perform the transformation

The result image will be loaded into a new window where you can edit it as any other image.

==== Inserting ====
Once you are done with editing the image you can either insert it back to your orignal pano or load it as a masked layer.

===== Merging =====
You need to have checked 'Save to Buffer' in order to be able to merge the result into your pano.
* With the edited rectilinear image as foremost (active) document open Adjust or PTAdjust dialog from the filter menu.
* Choose 'Insert' and 'Use Options' and press 'Set'
* in the following dialog leave anything as is or set it to the values described in the Extracting part if you changed them meanwhile with these exceptions:
* In the 'Panorama' section:
** Uncheck 'Save to Buffer'
** Check 'Load Buffer'
** check 'or paste'
** Choose 'Color Correction: none'
** Set 'Feather:' to a small value or 0
* Press 'Ok' twice to perform the transformation ans merging.

===== Loading as layer =====
Sometimes it might be usefull to load only the transformed Nadir or Zenith image in order to insert it as a new layer into a panorama.
* With the edited rectilinear image as foremost (active) document open Adjust or PTAdjust dialog from the filter menu.
* If you changed any settings since extracting the image set them as described under Extracting.
* Press 'Ok' to perform the transformation

The image is loaded as a document containing an [[alpha channel]] with the mask. In photoshop you can move this into a masked layer:
* In the layers palette double click the layer thumbnail in order to create a layer from background.
* Choose 'Load Selection' from the 'Select' menu.
* Choose 'Channel: Alpha 1' as new selection and press 'Ok'
* Click the 'Add vector mask' button in the bottom line of the layers palette.
* Shift-Drag (pres and hold the shift key after started dragging) the layer from the layers palette to your original panorama.

=== PTStitcher ===
[[PTStitcher]] supports 16 bit images and can be used to extract and insert partial views in different ways.
* By directly scripting it.
* With [[PanoCube]] Plus
* By one of it's GUIs ([[PTGui]], [[PTAssembler]], [[Hugin]], [[PTMac]]...)

[[nona]] is a free alternative to [[PTStitcher]] that can be used as a drop-in replacement if [[PTStitcher]] is not available.

==== Scripts ====
There are several scripts or batch files available that extract 6 cube faces from an [[Equirectangular Projection]] image. One of the most convenient windows batch file is written by Eric Gerds and part of his [http://www.pinlady.net/vr/#anchor3 DOS Utilities for Panoramas]. A less convenient batch file is found on [http://www.erik-krause.de/ttt Erik Krause's ] page. [[PTStitcher]] scripts are found on [http://www.path.unimelb.edu.au/~bernardk/tutorials/360/readme/scripts.html Ben Kreunen's ] page

==== PanoCube Plus ====
[[PanoCube]] Plus can extract six cube faces (single, batch modes) for editing and then convert it directly into [[QTVR]] cubic movie(s). Both 8/16 bits per channel are supported - depending on the [[pano12]] library used the cube faces are the same bit depth as the source images.

To activate "equirectangular to 6 cube faces" mode copy the file <code>Script.txt</code> to the folder where your source image is and set "1" as first character in this line using a text editor (notepad!):

<pre>1 # create tiles for editing ( 0 = NO, 1 = YES). Default NO.</pre>

in the file <code>Script.txt</code> and put it into pano's folder. Next drag and drop your single pano or folder with panos onto the program icon. The source file name and path should contain no spaces. The source image must be exactly in 2:1 format (f.e. 2000x1000 or 6000x3000 pixels). [[PanoCube]] calls [[PTStitcher]] 6 times and creates 6 files in the order front, right, back, left, top, bottom and replaces the last two characters of the name with 11, 22, 33, 44, 55, 66. All files ended with 55 are represent zenith view, ended with 66 - nadir view.

After editing drag again any one (not all!) tile or folder with tiles to get [[QTVR]] cubic movie(s). In batch mode important to have first six letters differ in filenames, otherwice PanoCube can skips "similar" files.

This technique is good if the final product is a [[QTVR]] movie. If you need an equirectangular for PTViewer you can of course drag the .mov file on panocube plus to get it converted, but image quality suffers because of intermediate [[JPEG]] compression and decompression and another [[interpolation]] step.

==== Inserting cubefaces again ====
You can assemble the cube faces again using the [[PTGui]] template from http://www.erik-krause.de/ttt or the batch file from Eric Gerds: [http://www.pinlady.net/vr/#anchor3 Dos for Panoramas].

You can even remap only one cube face to equirectangular and insert it as an additional layer into your layered photoshop document. This has several benefits:
* no additional [[interpolation]] for the rest of the panorama.
* possibility to patch nadir in a relative early stage of editing thus leaving open any possibility of correcting over all colors etc.
* preserving as much as possible of the original image data

To re-insert the patched cubeface into the original document implies that you have worked on a cube face with enough resolution, preferable the pixel width of the original pano divided by 3.

You can use the batch file or [[PTGui]] template mentioned above. You simply have to set output size equal to your original panorama size and create single image [[TIFF]]s as output. Any of those [[TIFF]] files can be added to the original panorama as a masked layer using the "Tiff to masked layers" action from http://www.erik-krause.de/ttt

To use any of the other GUIs you need to
* Add the cube face as input image
* specify [[Rectilinear Projection|rectilinear]] and FoV 90° for input images
* set all lens correction parameters to 0.0
* specify the correct yaw and pitch values for the particular image:
<pre>
tile front right back left top bottom
Yaw 0 90 180 -90 0 0
Pitch 0 0 0 0 90 -90
</pre>
* specify the correct output size.
* specify [[TIFF]] without mask or feather (TIFF_m) as output format.
* don't set control points and don't optimize
* create the panorama

==== GUI ====
All of the [[GUI front-ends]] should be capable of extracting an arbitrary [[Rectilinear Projection|rectilinear]] view from a spherical pano. Use the equirect image as input (don't forget to set the correct FoV) and specify a rectilinear image with 90° as output "panorama". Set all lens correction parameters to 0.0. Then change yaw and pitch of the input image until you get the desired view. Note that the values work the other way round than when inserting an image.

==== PTGui ====
[[PTGui]] offers an additional advantage: The panorama editor and numerical transform. To use it load your image as described above, open panorama editor and choose 'Numerical Transform' from the edit menu.

On the 'Panorama Settings' tab don't forget to uncheck 'Use fast transform' (for details see [[#Warning|Warning]] at top of page).

To pan along the horizon f.e. in 20° steps insert 20 into the 'Yaw' field and press 'Apply' repeatedly until you get the desired view. Positive values pan right, negatives left.

Do the corresponding for 'Pitch' and 'Roll' if needed. This way you can extract any partial view. Once your are done create the "Panorama" (which is the desired partial view) using output format [[TIFF]]. Note down or save the exact values for Yaw, Roll and Pitch as shown on 'Image Parameters" tab page.

Now edit the partial view to your need. Then add it to the project with your original panorama and on 'Panorama settings' tab change to equirectangular and 360°x180°. Choose individual lens parameters for the new image on 'Lens settings' tab and set 'Rectilinear' and 90° on 'Image parameters' tab. The image should fit now perfectly in the original panorama.

In order to move the panorama back to it's original position go to panorama editor again and choose 'Numerical transform'. Now Enter the exact values for Yaw, Roll and Pitch you previously saved or noted down. The panorama should move back to it's original position now.

You can create either the complete panorama or the partial view only. Choose the size of the original panorama for output.

--[[User:Erik Krause|Erik Krause]] 18:30, 20 Mar 2005 (EST)

[[Category:Tutorial:Basic need]]

User:Zbooy

2007-03-19T11:53:58Z

Zbooy: /* Current Kit */

== Full Name ==
Szymon Madej, aka Zbooy

== Location ==
Close enough to N50 E20

== Current Kit ==
Canon DSLRs, Nikkor & Zenitar fisheyes, Tamron wide-angle 
Manfrotto tripods, NN3, Agnos & KingPano heads 
...and lots of strange paraphernalia :-)

== Sphericals ==

[http://panoramy.zbooy.pl/360/ panoramy.zbooy.pl/360]

HDR Software overview

2007-03-10T23:10:25Z

Zbooy: /* Software overview */ Updated price of EasyHDR

=HDR software overview=

Certainly one of the most interesting upcoming technologies for photographers is High Dynamic Range Imaging (HDRI), allowing to work with the full real world levels of illumination. While standard image formats utilizes 8 or 16 bits with applied Gamma and color space, the HDR image format extends the bit depth up to 96bit in a linear color space.

On this overview we will focus on the currently available Windows GUI-based software packages that are able to create and process HDR images. I want to thank all authors of the respective software packages for their support during the creation of the overview, especially Geraldine Joffre, Andreas Schömann, Paul Nolan, and Thomas Lock. Aside from the windows based GUI packages Bernhard Vogl has evaluated, command line tools are also available and have been added to the table below.

The following software packages have been tested:

==Software overview==

{| border="1" cellpadding="5"
|-
| bgcolor="#000000" | '''Software'''
| bgcolor="#000000" | '''Homepage'''
| bgcolor="#000000" | '''Version'''
| bgcolor="#000000" | '''Platforms'''
| bgcolor="#000000" | '''Price'''
| bgcolor="#000000" | '''comments'''
|-
| '''Artizen'''
|
[http://www.supportingcomputers.net/ www.supportingcomputers.net]
| 2.4.8
| Win
| 59.99 CDN
| -
|-
| '''EasyHDR'''
|
[http://www.easyhdr.com easyhdr.com]
| 1.22
| Win
| 25 EUR
| -
|-
| '''FDRTools Basic '''
|
[http://fdrtools.com/ fdrtools.com]
| 1.8.2
| Win, Mac
| free
| -
|-
| '''FDRTools Advanced'''
|
[http://fdrtools.com/ fdrtools.com]
| 1.8.2
| Win, Mac
| 39.00 EUR
| -
|-
| '''HDRShop'''
|
[http://gl.ict.usc.edu/HDRShop/ gl.ict.usc.edu/HDRShop]
| 1.0
| Win
| free for non-commercial and educational use (commercial license: HDRShop 2 (399.00 USD))
| no further development, superseded by the commercial version 2.0
|-
| '''Photogenics HDR'''
|
[http://www.idruna.com/ www.idruna.com]
| 7.0
| Win, Linux
| 699.00 USD
| focuses on 3D workflow and film editing
|-
| '''Photomatix Pro'''
|
[http://www.hdrsoft.com/ www.hdrsoft.com]
| 2.3.1
| Win, Mac
| 99.00 USD
| -
|-
| '''Photoshop'''
|
[http://www.adobe.com/ www.adobe.com]
| 9.0 (CS2)
| Win, Mac
| 649.00 USD (US download) 1042.84 EUR (Europe boxed)
| -
|-
| '''Picturenaut'''
| No Homepage ([http://www.dslr-forum.de/showthread.php?t=61750 download here])
| 1.9b (beta)
| Win
| free
| German only software
|-
| '''pfstools'''
|
[http://www.mpi-sb.mpg.de/resources/pfstools/ www.mpi-sb.mpg.de]
| 1.5
| Unix, Mac, (Win)
| free, open source
| Command line tools and two GUI (pfsview and [http://theplaceofdeadroads.blogspot.com/2006/07/qpfstmo-hdr-tone-mapping-gui-for-linux_04.html qpfstmo]) for creation and processing of hdr images.
|-
|}

As you can see,there is a wide variety of fees you have to pay for the different software packages. This is partly justified by the features and the editing functions the various programs offer.

==HDR creation and tonemapping==

{| border="1" cellpadding="5"
|-
| rowspan="2" bgcolor="#000000" | '''Software'''
| rowspan="2" bgcolor="#000000" |
<center>measure camera response curve</center>
| colspan="4" bgcolor="#000000" |
<center>create HDR from bracketed images</center>
| rowspan="2" bgcolor="#000000" align="center" | create HDR from camera RAW image (*1)
| colspan="5" bgcolor="#000000" align="center" | tonemap image to LDR
|-
| bgcolor="#000000" align="center" | single HDR image creation
| bgcolor="#000000" align="center" | batch mode
| bgcolor="#000000" align="center" | LDR image alignment
| bgcolor="#000000" align="center" | ghost removal
| bgcolor="#000000" align="center" | number of different operators
| bgcolor="#000000" align="center" | single image via GUI
| bgcolor="#000000" align="center" | batch mode
| bgcolor="#000000" align="center" | parameters save-/restoreable
| bgcolor="#000000" align="center" | panoramic mapping (correct border and zenith/nadir blending)
|-
| '''Artizen'''
| align="center" | <big>○</big> (histogram)
| align="center" | √
| align="center" | √
| align="center" | manual
| align="center" | ?
| align="center" | √
| align="center" | 11
| align="center" | √
| align="center" | √
| align="center" | √
| align="center" | –
|-
| bgcolor="#FFFFFF" | '''EasyHDR'''
| bgcolor="#FFFFFF" align="center" | ?
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | manual ?
| bgcolor="#FFFFFF" align="center" | ?
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | 1
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | during creation
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#F5F5F5" | '''FDRTools Basic'''
| bgcolor="#F5F5F5" align="center" | √ & modify-able histogram
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (via command line)
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" |
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | 2
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (via command line)
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" |
|-
| bgcolor="#F5F5F5" | '''FDRTools Advanced'''
| bgcolor="#F5F5F5" align="center" | √ & modify-able histogram
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (via command line)
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | 3 (also supports compression & contrast bracketing)
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (via command line)
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | √
|-
| bgcolor="#FFFFFF" | '''HDRShop'''
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#F5F5F5" | '''Photogenics HDR'''
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | √ (relies on EXIF data)
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | ?
| bgcolor="#F5F5F5" align="center" | ?
| bgcolor="#F5F5F5" align="center" | – (tethered shooting with Canon cameras possible)
| bgcolor="#F5F5F5" align="center" | 3
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
|-
| bgcolor="#FFFFFF" | '''Photomatix Pro'''
| bgcolor="#FFFFFF" align="center" | √ (selectable)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √ (selectable)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | 2 + 2 LDR blending methods
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (no zenith/nadir possible)
|-
| bgcolor="#F5F5F5" | '''Photoshop'''
| bgcolor="#F5F5F5" align="center" | √ (supposedly automatic)
| bgcolor="#F5F5F5" align="center" | √ (relies on EXIF data)
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | √ (selectable)
| bgcolor="#F5F5F5" align="center" | ?
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | 4
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | –
|-
| bgcolor="#FFFFFF" | '''Picturenaut'''
| bgcolor="#FFFFFF" align="center" | √ (selectable)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (via command line)
| bgcolor="#FFFFFF" align="center" | √ (selectable)
| bgcolor="#FFFFFF" align="center" | ?
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | 2
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √/– (can read MKHDRI-curves)
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#FFFFFF" | '''pfstools'''
| bgcolor="#FFFFFF" align="center" | √ (pfscalibration, pfstmo with qpfstmo GUI)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (via command line)
| bgcolor="#FFFFFF" align="center" | -
| bgcolor="#FFFFFF" align="center" | -
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | 7
| bgcolor="#FFFFFF" align="center" | √ (qpfstmo)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | -/– (command line)
| bgcolor="#FFFFFF" align="center" | –
|}

<nowiki>*1: Most software relies on DCRaw for RAW conversion. Some cameras with extended DR capabilities are not converted correctly (e.g. Fuji's S3 camera: Although DCRaw could theoretically read all photosensors, it would need one conversion call for every photosite which is not implemented in the testes software packages.)</nowiki>

==HDR image manipulation==

{| border="1" cellpadding="5"
|-
| colspan="11" align="center" |
There are basically 2 types of appications available:
* Converter software: This type of software will assist you in generating and tonemapping HDR images
* Image editors: These are full-flagged image manipulation programs that will also give you the possibility of HDR generation and tonemapping
|-
| rowspan="2" bgcolor="#000000" align="center" | '''Software'''
| bgcolor="#000000" align="center" | File formats (*1) EXR/HDR: 96bit TIFF: 32bit
| rowspan="2" bgcolor="#000000" align="center" | software type
| rowspan="2" bgcolor="#000000" align="center" | full image editing capabilities
| colspan="2" bgcolor="#000000" align="center" | manipulation essentials
| rowspan="2" bgcolor="#000000" align="center" | no. of builtin panoramic transformations
| colspan="3" bgcolor="#000000" align="center" | filters
| rowspan="2" bgcolor="#000000" align="center" | plugins possible
|-
| bgcolor="#000000" align="center" | read/write
| bgcolor="#000000" align="center" | resize, crop, rotate
| bgcolor="#000000" align="center" | white balance
| bgcolor="#000000" align="center" | approx number
| bgcolor="#000000" align="center" | HDR capable
| bgcolor="#000000" align="center" | scriptable
|-
| bgcolor="#F5F5F5" | '''Artizen'''
| bgcolor="#F5F5F5" | EXR, HDR, TIFF, PFM
| bgcolor="#F5F5F5" align="center" | image editor
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (color adjust)
| bgcolor="#F5F5F5" align="center" | 4
| bgcolor="#F5F5F5" align="center" | >40
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | Tone Mapping Operator SDK included
|-
| bgcolor="#FFFFFF" | '''EasyHDR'''
| bgcolor="#FFFFFF" | HDR, TIFF
| bgcolor="#FFFFFF" align="center" | converter
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#F5F5F5" | '''FDRTools Basic'''
| bgcolor="#F5F5F5" | EXR, HDR, TIFF
| bgcolor="#F5F5F5" align="center" | converter
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
|-
| bgcolor="#F5F5F5" | '''FDRTools Advanced'''
| bgcolor="#F5F5F5" | EXR, HDR, TIFF
| bgcolor="#F5F5F5" align="center" | converter
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | –
|-
| bgcolor="#FFFFFF" | '''HDRShop'''
| bgcolor="#FFFFFF" | HDR, TIFF
| bgcolor="#FFFFFF" align="center" | converter
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | 6 (+ 3D rotation)
| bgcolor="#FFFFFF" align="center" | ~15
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √
|-
| bgcolor="#F5F5F5" | '''Photogenics HDR'''
| bgcolor="#F5F5F5" | EXR, HDR, TIFF
| bgcolor="#F5F5F5" align="center" | image editor
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (color adjust)
| bgcolor="#F5F5F5" align="center" | 4
| bgcolor="#F5F5F5" align="center" | >40
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | √ (beta)
|-
| bgcolor="#FFFFFF" | '''Photomatix Pro'''
| bgcolor="#FFFFFF" | EXR, HDR, TIFF
| bgcolor="#FFFFFF" align="center" | converter
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | 1
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#F5F5F5" | '''Photoshop'''
| bgcolor="#F5F5F5" | EXR, HDR, TIFF (always assumes 32bit)
| bgcolor="#F5F5F5" align="center" | image editor
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | <big>○</big> (white point adjust)
| bgcolor="#F5F5F5" align="center" | –
| bgcolor="#F5F5F5" align="center" | >40
| bgcolor="#F5F5F5" align="center" | ~15
| bgcolor="#F5F5F5" align="center" | √
| bgcolor="#F5F5F5" align="center" | √
|-
| bgcolor="#FFFFFF" | '''Picturenaut'''
| bgcolor="#FFFFFF" | HDR, TIFF
| bgcolor="#FFFFFF" align="center" | converter
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#FFFFFF" | '''pfstools'''
| bgcolor="#FFFFFF" | EXR, HDR, JPEG-HDR (read only), PFM, TIFF
| bgcolor="#FFFFFF" align="center" | converter
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | –
| bgcolor="#FFFFFF" align="center" | 4
| bgcolor="#FFFFFF" align="center" | ~11
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | n/a
|}

<nowiki>*1: TIFF: 32 bit floating point TIFF. Please note that the TIFF file format is an abstract container for various encoding methods. This may result in incompatibility when exchanging TIFF files between various applications.</nowiki> This is also true to some extent for .hdr files. Though, all applications in this overview use the most recent file format.

==UI functionality and large image processing==

{| border="1" cellpadding="5"
|-
| colspan="5" align="center" |
The best HDR software is not of much use if it lacks of an intuitive user interface. We will now have a look on some key functionality and UI design. We will also have a look if the applications utilize a clever memory management. The test file is a HDR panorama stitched by Hugin with a size of 8000x4000 pixels (32 Mpix), converted to the Radiance (.hdr) format. (This is tested using a standard Windows XP setup w. 1GB of RAM, swapping to HDD allowed)
|-
| rowspan="2" bgcolor="#000000" align="center" | '''Software'''
| colspan="2" bgcolor="#000000" align="center" | drag & drop operation from operating system possible
| colspan="2" bgcolor="#000000" align="center" | large image processing
|-
| bgcolor="#000000" align="center" | drop JPEG LDR images → generate HDR image
| bgcolor="#000000" align="center" | drop HDR image
| bgcolor="#000000" align="center" | load 32Mpix HDR file
| bgcolor="#000000" align="center" | tone map 32Mpix image
|-
| '''Artizen'''
| align="center" | yes / no (will open single images for editing)
| align="center" | yes
| align="center" | √
| align="center" | √
|-
| bgcolor="#FFFFFF" | '''EasyHDR'''
| bgcolor="#FFFFFF" align="center" | no / no
| bgcolor="#FFFFFF" align="center" | no
| bgcolor="#FFFFFF" align="center" | runtime error
| bgcolor="#FFFFFF" align="center" | –
|-
| bgcolor="#FFFFFF" | '''FDRTools Basic'''
| bgcolor="#FFFFFF" align="center" | no / no
| bgcolor="#FFFFFF" align="center" | no
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (very slow)
|-
| bgcolor="#FFFFFF" | '''FDRTools Advanced'''
| bgcolor="#FFFFFF" align="center" | no / no
| bgcolor="#FFFFFF" align="center" | no
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (very slow)
|-
| '''HDRShop'''
| align="center" | √ / no (will open multiple images for editing)
| align="center" | √
| align="center" | √
| align="center" | n/a
|-
| bgcolor="#FFFFFF" | '''Photogenics HDR'''
| bgcolor="#FFFFFF" align="center" | √ / no (will open multiple images for editing)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | <big>○</big> (very slow)
|-
| '''Photomatix Pro'''
| align="center" | √ / √
| align="center" | √
| align="center" | √
| align="center" | √ (only in batch mode)
|-
| bgcolor="#FFFFFF" | '''Photoshop'''
| bgcolor="#FFFFFF" align="center" | √ / no (will open multiple images for editing)
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
| bgcolor="#FFFFFF" align="center" | √
|-
| '''Picturenaut'''
| align="center" | no / no
| align="center" | no
| align="center" | √
| align="center" | √
|-
| '''pfstools'''
| align="center" | no / no
| align="center" | no
| align="center" | n/a (no GUI)
| align="center" | √ (depends on algorithm)
|}

--> next Page:

=[[HDR and Tonemapping dialogs in detail]]=

--[[User:Bvogl|Bvogl]] 12:13, 25 November 2006 (CET)

SmartBlend

2007-01-03T19:16:24Z

Zbooy: typos and grammatical errors

==What it is==
Smartblend is an application for seamless image blending by Michael Norel. He can be reached at minorlogic{at}yahoo{dot}com

The main goal of smartblend is panoramic image blending, though it can be used for other applications, such as creation of seamless textures, montage of photos or collage. Smartblend allows stitching of many problematic shots (parallaxed, with moving objects or with differing exposure).

For example see the parallax picture below (from http://www.htu.at/~sascha/ptguide/01.htm described as "impossible to stitch" )
[[Image:SB_Parallax.jpg|left]]{{clr}}

Just put one picture into another and note the great difference.
[[Image:SB_Parallax_overlapped.jpg|left]]{{clr}}

Picture below is blended by smartblend.
[[Image:SB_Blended.jpg|left]]{{clr}}
Another smartblend example: http://www.liamphoto.com/subwebs/flam-chen/flamchen.htm

If you don't know what is a "command line application" it can not be useful for you. But you still can use a frontend for smartblend:

* [[PanoWizard]]
* [[EnblendGUI]]
* [[PTGui]]
* [[PTAssembler]]

Download SmartBlend [[Media:smartblend_1_2_2.zip|smartblend_1_2_2.zip]] (16 bit + big files support)

Please test new beta version [[Media:smartblend_1_2_3b0.zip|smartblend_1_2_3b0.zip]]

==How it works==

It finds the visual error on overlap region and searches for a seam line with minimal visual error. Than it blends pictures using an algorithm similar to a multiresolution spline.

To study algorithms and options use “–SeamVerbose” and “-PyramidVerbose” commands.

There is a [http://qtvr.by.ru/NewQTWR/sm/smartblend.htm good tutorial], but it's available only in Russian. Anyone to translate it?

Welcome to anyone who wants to improve this smartblend, write a tutorial and other.

--[[User:Erik Krause|Erik Krause]] 15:39, 20 July 2006 (CEST) (Text taken from original smartblend home page)

[[Category:Software:Platform:Windows]]

Extract and insert rectilinear views

2006-11-04T23:13:02Z

Zbooy: typo

Contrast Blending

2006-08-22T21:07:28Z

Zbooy: typo

We refer to '''contrast blending''' as a technique to blend several differently exposed (exposure [[Bracketing|bracketed]]) images in order to achieve a higher [[Dynamic range]].

There are several more or less automatic approaches realized in commercial programs or plugins like [[Photomatix]], [http://fdrtools.com/ FDRTools] and Fred Miranda's [http://www.fredmiranda.com/DRI/ DRI], the free [[photoshop]] actions from [[Contrast Blending Actions|Erik Krause]], or [http://turtle.as.arizona.edu/jdsmith/exposure_blend.php exposure-blend], a script suite for the [[Gimp]].

However, contrast blending can be done completely 'by hand' as described on Michael Reichmann's site - http://www.luminous-landscape.com/tutorials/digital-blending.shtml
or like described in [[A simple approach to HDR-blending]]

Here is a user comment on Michael's technique:

"I use the second technique, the Layer Mask approach, and have found that it works quickly and easily, while still leaving much room for tweaking as necessary. The only change I've made in my approach is at the end where I work in Levels instead of curves. I find that sliding the mid-tones to the right helps make the resulting image look more realistic. In some cases, you just have to play around with all three sliders until you get a good blend. I also will reduce the opacity of the top layer down to about 85% as well."

Here is a fragment of an [[ImageMagick]] script by Peter Gawthrop that can be used to automate contrast blending:

normal=$1
under=$2
over=$3

### Merge under exposure
## Mask for under exposed
convert -type Grayscale $under _mask.tif
## Masked version
composite -compose CopyOpacity _mask.tif $under _under_masked.tif
## Merge with background
composite -compose Darken _under_masked.tif $normal _composite.tif

### Merge over exposure
## Mask for over exposed
convert -negate -type Grayscale $over _mask.tif
## Masked version
composite -compose CopyOpacity _mask.tif $over _over_masked.tif
## Merge with background
composite -compose Lighten _over_masked.tif _composite.tif merged.tif

The other way to use bracketed exposures is to assemble them into a single [[HDR]] image. This can be done with free [http://projects.ict.usc.edu/graphics/HDRShop/ HDRShop], new [[Photoshop]] CS2, [[cinepaint]] ([http://people.freenet.de/hsbosny/HDR_Tutorial/HDR_Tutorial-en.html tutorial for using cinepaint here]) or [http://www.mpi-inf.mpg.de/resources/hdr/calibration/pfs.html PFScalibration] and the [http://fdrtools.com/fdrexposer/fdrexposer_e.php FDRExposer]. The problem here is that the HDR image must be compressed to reveal the complete contrast range on a computer monitor.

This was a major problem for [[HDRShop]] since only [[gamma]] adjustment or (later) the Reinhard [[tone mapping]] plugin existed. It is still a problem for Photoshop CS2, but here the [[HDR]] images can be converted to a 16 or 8 bit per channel image with more possibilities. Brian Greenstone wrote a nice tutorial about that: [http://www.panomundo.com/panos/howto/workflow_expbracketing.html]

Meanwhile two Photoshop CS2 plugins are available that deal with that problem: [[Photomatix]] and FDRCompressor. See [[HDR compression]] for details.

There are several tools that can handle HDR images: [[enblend]], [[Hugin]] and [[Nona]] can work with HDR images of different flavours. [[PTViewer]] 3.1 can display HDR images with adaptive [[dynamic range]] directly. For Linux there are several open source command line tools available that implement different [[tone mapping]] algorithms: [http://www.mpi-sb.mpg.de/resources/pfstools/]

Mark Fink [http://www.northernlight.net www.northernlight.net]
[[Category:Glossary]][[Category:Tutorial]][[Category:Tutorial:Specialised]]

User:Zbooy

2006-08-22T21:05:09Z

Zbooy:

== Full Name ==
Szymon Madej, aka Zbooy

== Location ==
Close enough to N50 E20

== Current Kit ==
Canon DSLRs, Nikkor & Zenitar fisheyes, Tamron wide-angle 
Manfrotto tripod and KingPano head 
...and lots of strange paraphernalia :-)

== Sphericals ==

[http://panoramy.zbooy.pl/360/ panoramy.zbooy.pl/360]

Amateur photographers

2006-08-22T20:58:21Z

Zbooy: /* M */

Please add the entry alphabetically to the list.

{{CompactTOC}}

== A ==

== B ==

== C ==

== D ==

Denis Roncali ---
[http://www.denisroncali.it/Fotografie/FrigoEcomin01/FrigoEcomin01-2400.html claustropano 1] -
[http://www.denisroncali.it/Fotografie/FornoCasa01/FornoCasa01-2400.html claustropano 2] -
[http://www.denisroncali.it/Fotografie/LavatriceCasa01/LavatriceCasa01-2400.html claustropano 3]

Richard Drew ---
[http://www.add360.com/virtual_tour_panoramic_samples.htm Some Samples]

== E ==

== F ==

== G ==

== H ==

[[User:Smensch01|Stefan Henze]]

== I ==

== J ==

== K ==

== L ==

== M ==

[[User:Serge|Serge Maandag]] 
[[User:Zbooy|Szymon "Zbooy" Madej]] 
[[User:Geoff Mather| Geoff Mather]] 

== N ==

== O ==

== P ==
[[photopla.net|Photopla.net aka Yuval Levy]]

== Q ==

== R ==

== S ==
[[User:Jeff|Jeff Stephens]]

[[User:Rudi|Rudi Szabo]]

== T ==

== U ==

== V ==

== W ==

== X ==

== Y ==

== Z ==

== 0 - 9 ==

== others ==

Projections

2006-08-17T19:53:56Z

Zbooy: typo

Representing a spherical view of the world on a flat computer monitor or print requires some manner of mapping from the 3D spherical scene in which the camera and viewer are embedded to the 2D medium on which they are rendered. The techniques used for mapping are of exactly the same type long used by map makers to project the entire globe, or portions of it, onto two dimensional maps. There is no single, unique projection for representing sections of the sphere on the globe. Instead, all projections have various attributes and limitations. There are many classes of projections used for various purposes (e.g. [http://mathworld.wolfram.com/MapProjection.html Mathword's Projection Page]), but only a few are traditionally used for panoramic imaging.

'''First - a word of warning: If you are looking for a projection, that will map a spherical (even partial) panorama on a flat surface without bending lines: This won't work!'''

This link explains well why it is impossible: http://www.progonos.com/furuti/MapProj/Normal/CartDef/MapDef/mapDef.html

Some of the most common projections when working with Panoramic imaging are:

== Equirectangular projection ==
[[image:big_ben_equirectangular.jpg|thumb|200px|right|[[Equirectangular Projection]]]]
Also called the "non-projection", this is a representation of the sphere which maps longitude directly to the horizontal coordinate, and latitude to the vertical coordinate. This projection is often used for the source images in panoramic viewers like [[PTViewer]]. See definition for [[Equirectangular Projection]] for more.
{{clr}}

== Cylindrical projection ==
[[image:big_ben_cylindrical.jpg|thumb|200px|right|[[Cylindrical Projection]]]]This is the projection most commonly used for printed panoramas with a large range of longitude (>120 degrees). It can be envisioned by imagining wrapping a flat piece of paper around the sphere tangent to the equator, and projecting a light out from the center of the sphere. A full range of longitude, up to 360 degrees, can be represented with a cylindrical projection, but near the poles, the images become very distorted, so a full range of latitude cannot be used. See [[Cylindrical Projection]] for more.
{{clr}}

== Rectilinear projection ==
[[image:big_ben_rectilinear.jpg|thumb|150px|right|[[Rectilinear Projection]]]]
This is a fundamental projection which can be envisioned by imagining placing a flat piece of paper tangent to a sphere and projecting a light out from its center. Obviously, only less than 180 degrees of longitude can be represented with this projection (exactly 180 degrees would require an image of infinite width), and in practice, far less.

Most non-fisheye cameras produce a nearly rectilinear image over their field of view (albeit with varying amounts of unavoidable [[Lens_distortion|distortion]]). The Rectilinear projection is often used for prints of panoramas which cover less than ~120 degrees of longitude, since straight lines are preserved. See [[Rectilinear Projection]] for more.
{{clr}}

== Cubic projection ==
[[image:big_ben_cubic.jpg|thumb|200px|right|[[Cubic Projection]]]]
Technically a sub-case of the [[Rectilinear Projection]], the cubic projection is used as the source projection for fully spherical [[Quicktime]] VR panoramas. See [[Cubic Projection]] for more.
{{clr}}

== Fisheye projection ==
[[image:big_ben_fisheye.jpg|thumb|150px|right|[[Fisheye Projection]]]]
In a [[Fisheye Projection]], the distance from the centre of the image to a point is proportional to the equivalent spatial angle.
{{clr}}

== Stereographic projection ==
[[image:big_ben_stereographic.jpg|thumb|150px|right|[[Stereographic Projection]]]]
[[Stereographic Projection]] is a ''conformal'' form of [[Fisheye Projection]] where the distance from the centre is ''not'' equivalent to the spatial angle. This is much easier on the eye for printing and display purposes.

Stereographic is limited to a maximum horizontal (and vertical) angle of 360 degrees, images over 330 degrees are pretty, but not very usable.
{{clr}}

== Mercator projection ==
[[image:big_ben_mercator.jpg|thumb|200px|right|[[Mercator Projection]]]]
[[Mercator Projection]] is another ''conformal'' projection, similar to [[Cylindrical Projection]]. This shows less pronounced distortion than either ''cylindrical'' or [[Equirectangular Projection]] which otherwise look very similar.
{{clr}}

== Transverse mercator projection ==
[[image:big_ben_transverse_mercator.jpg|thumb|100px|right|[[Mercator Projection|Transverse Mercator Projection]]]]
This is a [[Mercator Projection]] rotated 90 degrees, suitable for a long vertical image.

Transverse mercator is limited to a maximum horizontal angle of 180 degrees, though in practice images over 150 degrees are not very usable.
{{clr}}

== Sinusoidal projection ==
[[image:bin_ben_sinusoidal.jpg|thumb|200px|right|[[Sinusoidal Projection]]]]
[[Sinusoidal Projection]] is an ''equal area'' projection which makes it suitable for transmission of spherical images, as supported by the [[DevalVR]] viewer.

[[Category:Glossary]]

Projections

2006-08-17T19:53:25Z

Zbooy: typos

Representing a spherical view of the world on a flat computer monitor or print requires some manner of mapping from the 3D spherical scene in which the camera and viewer are embedded to the 2D medium on which they are rendered. The techniques used for mapping are of exactly the same type long used by map makers to project the entire globe, or portions of it, onto two dimensional maps. There is no single, unique projection for representing sections of the sphere on the globe. Instead, all projections have various attributes and limitations. There are many classes of projections used for various purposes (e.g. [http://mathworld.wolfram.com/MapProjection.html Mathword's Projection Page]), but only a few are traditionally used for panoramic imaging.

'''First - a word of warning: If you are looking for a projection, that will map a spherical (even partial) panorama on a flat surface without bending lines: This won't work!'''

This link explains well why it is impossible: http://www.progonos.com/furuti/MapProj/Normal/CartDef/MapDef/mapDef.html

Some of the most common projections when working with Panoramic imaging are:

== Equirectangular projection ==
[[image:big_ben_equirectangular.jpg|thumb|200px|right|[[Equirectangular Projection]]]]
Also called the "non-projection", this is a representation of the sphere which maps longitude directly to the horizontal coordinate, and latitude to the vertical coordinate. This projection is often used for the source images in panoramic viewers like [[PTViewer]]. See definition for [[Equirectangular Projection]] for more.
{{clr}}

== Cylindrical projection ==
[[image:big_ben_cylindrical.jpg|thumb|200px|right|[[Cylindrical Projection]]]]This is the projection most commonly used for printed panoramas with a large range of longitude (>120 degrees). It can be envisioned by imagining wrapping a flat piece of paper around the sphere tangent to the equator, and projecting a light out from the center of the sphere. A full range of longitude, up to 360 degrees, can be represented with a cylindrical projection, but near the poles, the images become very distorted, so a full range of latitude cannot be used. See [[Cylindrical Projection]] for more.
{{clr}}

== Rectilinear projection ==
[[image:big_ben_rectilinear.jpg|thumb|150px|right|[[Rectilinear Projection]]]]
This is a fundamental projection which can be envisioned by imagining placing a flat piece of paper tangent to a sphere and projecting a light out from its center. Obviously, only less than 180 degrees of longitude can be represented with this projection (exactly 180 degress would require an image of infinite width), and in practice, far less.

Most non-fisheye cameras produce a nearly rectilinear image over their field of view (albeit with varying amounts of unavoidable [[Lens_distortion|distortion]]). The Rectilinear projection is often used for prints of panoramas which cover less than ~120 degrees of longitude, since straight lines are preserved. See [[Rectilinear Projection]] for more.
{{clr}}

== Cubic projection ==
[[image:big_ben_cubic.jpg|thumb|200px|right|[[Cubic Projection]]]]
Technically a sub-case of the [[Rectilinear Projection]], the cubic projection is used as the source projection for fully spherical [[Quicktime]] VR panoramas. See [[Cubic Projection]] for more.
{{clr}}

== Fisheye projection ==
[[image:big_ben_fisheye.jpg|thumb|150px|right|[[Fisheye Projection]]]]
In a [[Fisheye Projection]], the distance from the centre of the image to a point is proportional to the equivalent spatial angle.
{{clr}}

== Stereographic projection ==
[[image:big_ben_stereographic.jpg|thumb|150px|right|[[Stereographic Projection]]]]
[[Stereographic Projection]] is a ''conformal'' form of [[Fisheye Projection]] where the distance from the centre is ''not'' equivalent to the spatial angle. This is much easier on the eye for printing and display purposes.

Stereographic is limited to a maximum horizontal (and vertical) angle of 360 degrees, images over 330 degrees are pretty, but not very usable.
{{clr}}

== Mercator projection ==
[[image:big_ben_mercator.jpg|thumb|200px|right|[[Mercator Projection]]]]
[[Mercator Projection]] is another ''conformal'' projection, similar to [[Cylindrical Projection]]. This shows less pronounced distortion than either ''cylindrical'' or [[Equirectangular Projection]] which otherwise look very similar.
{{clr}}

== Transverse mercator projection ==
[[image:big_ben_transverse_mercator.jpg|thumb|100px|right|[[Mercator Projection|Transverse Mercator Projection]]]]
This is a [[Mercator Projection]] rotated 90 degrees, suitable for a long vertical image.

Transverse mercator is limited to a maximum horizontal angle of 180 degrees, though in practice images over 150 degrees are not very usable.
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== Sinusoidal projection ==
[[image:bin_ben_sinusoidal.jpg|thumb|200px|right|[[Sinusoidal Projection]]]]
[[Sinusoidal Projection]] is an ''equal area'' projection which makes it suitable for transmission of spherical images, as supported by the [[DevalVR]] viewer.

[[Category:Glossary]]