Difference between revisions of "Hugin Stitcher tab"

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(notes on compression)
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the final output file is created.
 
the final output file is created.
  
= Panorama =
+
= Projection =
  
 
Here you can set the output '''[[Projections|Projection]]''' of your project, there are lots
 
Here you can set the output '''[[Projections|Projection]]''' of your project, there are lots
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* [[Rectilinear Projection|Rectilinear]], this is the same projection as a photo taken with a 'normal' camera and lens.  Use this if you are just stitching a handful of photographs together with a narrow [[Field of View]] or [[Perspective correction|correcting perspective]] in a single shot.
 
* [[Rectilinear Projection|Rectilinear]], this is the same projection as a photo taken with a 'normal' camera and lens.  Use this if you are just stitching a handful of photographs together with a narrow [[Field of View]] or [[Perspective correction|correcting perspective]] in a single shot.
* [[Cylindrical Projection|Panorama]], actually a simple [[Cylindrical Projection]] as used by traditional rotating panoramic cameras.  A good projection for printing a 360 degree panorama, though you may prefer ''Mercator Projection''.
+
* [[Cylindrical Projection|Cylindrical]], actually a simple [[Cylindrical Projection]] as used by traditional rotating panoramic cameras.  A good projection for printing a 360 degree panorama, though you may prefer ''Mercator Projection''.
 
* [[Equirectangular Projection|Equirectangular]], the all purpose format for representing an entire spherical scene.  It covers 360 degrees horizontally as well as the [[zenith]] and [[nadir]].
 
* [[Equirectangular Projection|Equirectangular]], the all purpose format for representing an entire spherical scene.  It covers 360 degrees horizontally as well as the [[zenith]] and [[nadir]].
 
* [[Fisheye Projection|Fisheye]], the same projection as a photo taken with a ''fisheye lens''.  Better for representing a wide [[Field of View]] than ''rectilinear'', but in many cases ''Stereographic Projection'' gives less distortion than simple ''fisheye''.
 
* [[Fisheye Projection|Fisheye]], the same projection as a photo taken with a ''fisheye lens''.  Better for representing a wide [[Field of View]] than ''rectilinear'', but in many cases ''Stereographic Projection'' gives less distortion than simple ''fisheye''.
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* [[Projections#Transverse mercator projection|Trans Mercator]], a ''mercator'' image rotated 90 degrees, suitable for displaying tall or overhead objects.
 
* [[Projections#Transverse mercator projection|Trans Mercator]], a ''mercator'' image rotated 90 degrees, suitable for displaying tall or overhead objects.
 
* [[Projections#sinusoidal projection|Sinusoidal]], an ''equal area'' projection of an entire spherical scene.
 
* [[Projections#sinusoidal projection|Sinusoidal]], an ''equal area'' projection of an entire spherical scene.
* [[Lambert Equal Area Conical Projection|Lambert Equal Area Conical]]
+
* [[Lambert Equal Area Cylindrical Projection|Lambert Cylindrical Equal Area]]
 
* [[Lambert Equal Area Azimuthal Projection|Lambert Equal Area Azimuthal]]
 
* [[Lambert Equal Area Azimuthal Projection|Lambert Equal Area Azimuthal]]
 
* [[Albers Equal Area Conic Projection|Albers Equal Area Conic]]
 
* [[Albers Equal Area Conic Projection|Albers Equal Area Conic]]
 
* [[Miller Cylindrical Projection|Miller Cylindrical]]
 
* [[Miller Cylindrical Projection|Miller Cylindrical]]
 +
* [[Panini]]
 +
* [[Architectural]]
 +
* [[Fisheye Projection|Orthographic]]
 +
* [[Fisheye Projection|Equisolid]]
 +
* [[Equirectangular Panini]]
 +
* [[Biplane]]
 +
* [[Triplane]]
 +
* [[The General Panini Projection|Panini General]]
 +
* [[Fisheye Projection|Thoby Projection]], is modeling the 10.5 mm Nikkor fisheye lens and was introduced with [http://hugin.sourceforge.net/releases/2011.0.0/en.shtml hugin 2011.0.0]. The projection is called after Michel Thoby who was able to empirically find it.
  
 
== Field of View ==
 
== Field of View ==
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* Transverse Mercator has to be less than 180 degrees horizontally.
 
* Transverse Mercator has to be less than 180 degrees horizontally.
  
== Panorama Canvas Size ==
+
== Canvas Size ==
  
 
Set the '''width''' and '''height''' of your output panorama in pixels.  '''Calculate Optimal Size''' will estimate
 
Set the '''width''' and '''height''' of your output panorama in pixels.  '''Calculate Optimal Size''' will estimate
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Note that the [[interpolation]] used by [[hugin]] doesn't handle downsampling very well, so output images smaller
 
Note that the [[interpolation]] used by [[hugin]] doesn't handle downsampling very well, so output images smaller
 
than about half the size of the ''Optimal Size'' will show [[aliasing]] artefacts.  If you want to create high quality
 
than about half the size of the ''Optimal Size'' will show [[aliasing]] artefacts.  If you want to create high quality
small images, it is better to create an ''Optimal Size'' image in hugin and downsize it later in an image editor such as the [[Gimp]].
+
small images, it is better to create an ''Optimal Size'' image in hugin and downsize it later in an image editor such as [[Gimp]].
  
 
== Crop ==
 
== Crop ==
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* Large 'gigapixel' style panoramas can be stitched in sections then blended later.
 
* Large 'gigapixel' style panoramas can be stitched in sections then blended later.
  
The cropped-out areas are shown darkened in the [[hugin Preview window]].
+
The cropped-out areas are shown darkened in the [[hugin Preview window|Preview window]].
 +
 
 +
The '''Fit Crop to Images''' button will automatically determine a crop that has a maximum number of pixels and no empty space.  This is the same function as the '''Autocrop''' button in the [[Hugin Fast Preview window|Fast Preview window]].  
  
 
== Output ==
 
== Output ==
  
Hugin can output 'normal' stitched images, [[exposure blending|exposure blended]] images or high dynamic range ([[HDR]]) images.
+
Hugin can output 'normal' stitched images, [[Exposure fusion|exposure fused]] images or high dynamic range ([[HDR]]) images.
 
The following options determine which kind of image is created, and allow keeping the intermediate images created during the process.
 
The following options determine which kind of image is created, and allow keeping the intermediate images created during the process.
  
 
=== Normal ===
 
=== Normal ===
  
If '''Blended panorama''' is enabled then [[enblend]] is used for blending. In the final stitching process [[nona]] reprojects and distorts images to fit, '''enblend''' takes these images as individual [[TIFF]] files and merges them using sophisticated seam positioning and blending.  Further '''enblend''' settings can be found in the [[hugin Preferences]].
+
If '''Exposure corrected, low dynamic range''' is enabled then [[enblend]] is used for blending. In the final stitching process [[nona]] reprojects and distorts images to fit, '''enblend''' takes these images as individual [[TIFF]] files and merges them using sophisticated seam positioning and blending.  Further '''enblend''' settings can be found in the [[hugin Preferences]].
  
Enable '''remapped images''' if you want to keep the intermediate images that '''enblend''' uses as input - For example modifying the [[alpha channel]] of these images and then blending manually is one technique for including and excluding people or objects that move between shots.
+
Enable '''Exposure corrected, low dynamic range''' under '''Remapped Images''' if you want to keep the intermediate images that '''enblend''' uses as input - For example modifying the [[alpha channel]] of these images and then blending manually is one technique for including and excluding people or objects that move between shots.
  
=== Exposure Blending ===
+
=== Exposure fusion ===
  
If '''Blended panorama (enfuse)''' is enabled then hugin will group the input images into exposure stacks by comparing positions and EV exposure values.  Each of these [[Bracketing|bracketed]] exposure stacks will be [[exposure blending|exposure blended]] with [[enfuse]] and the results stitched together into a panorama with [[enblend]].
+
If '''Exposure fused from stacks''' is enabled then hugin will group the input images into exposure stacks by comparing positions, any images with more than 70 % overlap are grouped like this.  Each of these [[Bracketing|bracketed]] exposure stacks will be [[Exposure fusion|exposure fused]] with [[enfuse]] and the results seam blended together into a panorama with [[enblend]].
  
Note that for this to work, the scene has to be photographed multiple times using exposure [[bracketing]] and the EV exposure values set either manually in the [[hugin Camera and Lens tab]], automatically from [[EXIF]] data or by optimising exposure in the [[hugin Assistant tab]] or [[hugin Exposure tab]].
+
Note that for this to work, the scene has to be photographed multiple times using exposure [[bracketing]] and the EV exposure values set either manually in the [[Hugin Photos tab|Photos tab]], automatically from [[EXIF]] data or by optimising exposure in the [[hugin Assistant tab]] or [[hugin Exposure tab]].
  
Note also that unlike '''Normal''' and '''Merge to HDR''' options where images are exposure corrected as part of the remapping process, enfuse requires that each exposure layer is supplied uncorrected - Hugin takes care of this automatically and will not apply correction in this case.
+
Note also that unlike '''Normal''' and '''HDR merging''' options where images are exposure corrected as part of the remapping process, enfuse requires that each exposure layer is supplied uncorrected - Hugin takes care of this automatically and will not apply exposure correction in this case.
  
Enable '''Blended exposure layers''' to additionally stitch each exposure layer into a separate panorama - Useful for manual exposure blending.
+
If '''Exposure fused from any arrangement''' is enabled then hugin will seam blend images with similar exposure with [[enblend]] and than it will [[Exposure fusion|exposure fuse]] them using [[enfuse]]. This variant is often much more successful than '''Exposure fused from stacks''' in two situations:
  
Enable '''Remapped images''' to keep the intermediate images supplied to [[enblend]].
+
* Where entire panoramas have been shot at each EV level consecutively rather than each shot [[Bracketing|bracketed]], in this case it isn't guaranteed that shots will line up into the approximate stacks expected by the '''Exposure fused from stacks''' option.
  
=== Merge to HDR ===
+
* When the panorama has been shot entirely on automatic exposure, in this situation it is useful to seam blend adjacent photos with small EV differences, but then exposure fuse larger EV differences - As effectively happens with this option.
  
If '''Blended HDR panorama''' is enabled then hugin will identify likely [[Bracketing|bracketed]] stacks of images, then create remapped, deghosted HDR images which are then blended with [[enblend]].
+
Note that Hugin uses a default threshold of 0.5 EV exposure difference to determine which photos can be fused into each layer. This threshold can be modified on the [[Hugin Photos tab|Photos tab]] in the Expert mode (selecting group by Output layers).
  
Note that like the Exposure blending option above, this generally only makes sense if the scene has been photographed multiple times using exposure bracketing, and the EV exposure values optimised in the [[hugin Exposure tab]].
+
Enable '''Blended layers of similar exposure, without exposure correction''' from '''Layers''' to keep exposure layers from the '''Exposure fused from any arrangement''' step, these are useful for manual [[Contrast Blending]].
  
Enable '''Stacked HDR images''' to keep copies of the remapped HDR images as supplied to enblend.
+
Enable '''No exposure correction, low dynamic range''' from '''Remapped Images''' to keep the intermediate images supplied to [[enblend]] and [[enfuse]].
  
Enable '''Individual non merged images''' to keep copies of each image remapped in linear colour space before deghosting and merging to HDR.
+
Normal '''Format''' can be in one several output file types:
  
Click '''Save project and stitch''' to generate output panoramas immediately (or '''Save project and send to batch''' to create a Makefile for later batch stitching - TODO doesn't work yet).
+
* '''[[TIFF]]''', various compression options. [[16bit]] and ''8bit'' depth supported.  '''None''' compression is supported by most other applications, '''LZW''' compression is common in Windows/Mac applications and '''Deflate''' compression is more common with Linux tools.
 +
* '''[[JPEG|JPG]]''', lossy compression suitable for web/email.  '''Quality''' can vary from ''0'' (extremely low quality, small file size) and ''100'' (high quality, large file size).  A typical quality setting for web/email would be between ''70'' and ''80''
 +
* '''[[PNG]]''', lossless compression. [[16bit]] and ''8bit'' depth supported.
 +
 
 +
=== HDR merging ===
 +
 
 +
If '''High dynamic range''' is enabled then hugin will identify likely [[Bracketing|bracketed]] stacks of images, then create remapped [[HDR]] images which are then blended with [[enblend]].
 +
 
 +
Note that like the Exposure fusion option above, this generally only makes sense if the scene has been photographed multiple times using exposure bracketing, and the EV exposure values optimised in the [[hugin Exposure tab]].
 +
 
 +
Enable '''High dynamic range merged stacks''' from '''Combined stacks''' to keep copies of the remapped HDR images as supplied to enblend.
 +
 
 +
Enable '''High dynamic range''' from '''Remapped Images''' to keep copies of each image remapped in linear colour space before merging to HDR.
 +
 
 +
Click '''Stitch now!''' to generate output panoramas immediately.  Selecting '''Save project and send to batch''' adds the current project to the [[Hugin Batch Processor]] stitching queue, note that the queue won't be processed unless this queue manager is running.
 +
 
 +
High dynamic range '''Format''' can be either:
 +
 
 +
* ''floating-point'' [[TIFF]], various compression options.
 +
* '''[[OpenEXR|EXR]]''', this is a high dynamic range format which is more compact than a high dynamic range TIFF.
  
 
= Processing =
 
= Processing =
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always '''save cropped images''' unless you need to open them in an image editor without [[Cropped TIFF]] support.
 
always '''save cropped images''' unless you need to open them in an image editor without [[Cropped TIFF]] support.
  
[[enblend]] is the default '''Blender''' for use with [[hugin]], normally there is no need to change this.  Additional command-line options can be set here or in the [[hugin Preferences]].
+
[[enfuse]] is the default for [[Exposure fusion]], '''Options''' are similar to [[enblend]].
  
== File formats ==
+
The default '''HDR merger''' is [[hugin_hdrmerge]].
  
'''Normal Output''' can be in one several formats:
+
[[enblend]] is the default '''Blender''' for use with [[hugin]], normally there is no need to change thisAdditional command-line '''Options''' can be set here or in the [[hugin Preferences]] for new projects.
 
+
* '''[[TIFF]]''', various compression options. [[16bit]] and ''8bit'' depth supported.  '''None''' compression is supported by most other applications, '''LZW''' compression is common in Windows/Mac applications and '''Deflate''' compression is more common with Linux tools.
+
* '''[[JPEG|JPG]]''', lossy compression suitable for web/email.  '''Quality''' can vary from ''0'' (extremely low quality, small file size) and ''100'' (high quality, large file size).  A typical quality setting for web/email would be between ''70'' and ''80''
+
* '''[[PNG]]''', lossless compression. [[16bit]] and ''8bit'' depth supported.
+
* '''[[OpenEXR|EXR]]''', not sure what use this is (TODO).
+
 
+
'''HDR Output''' can be either:
+
 
+
* ''floating-point'' [[TIFF]], various compression options.
+
* '''[[OpenEXR|EXR]]''', this is a high dynamic range format which is more compact than a high dynamic range TIFF.
+
  
 
__NOTOC__
 
__NOTOC__
 
[[Category:Software:Hugin]]
 
[[Category:Software:Hugin]]

Revision as of 09:55, 27 January 2013

The rest of hugin is all about setting up the project and aligning images, the Stitcher tab is where the final output file is created.

Projection

Here you can set the output Projection of your project, there are lots to choose from, each with different advantages and disadvantages:

Field of View

This is the horizontal and vertical angle of view of the output image, clicking Calculate Field of View will shrink or enlarge the field of view of the output to fit the arrangement of the input images - The Fit button in the Hugin Preview window does the same thing.

Note that some Projections have a limited field of view, notably:

  • Rectilinear has to be less than 180 degrees both vertically and horizontally.
  • Panoramic (cylindrical) has to be less than 180 degrees vertically.
  • Stereographic has to be less than 360 degrees both vertically and horizontally.
  • Mercator has to be less than 180 degrees vertically.
  • Transverse Mercator has to be less than 180 degrees horizontally.

Canvas Size

Set the width and height of your output panorama in pixels. Calculate Optimal Size will estimate a size that has about the same resolution as your input images.

Some examples: a three megapixel image has pixel dimensions of 2048 x 1536, an A4 print at 300 pixels per inch will have a pixel size of 3500 x 2480, a full screen spherical Equirectangular Projection image will have pixel dimensions of 6000 x 3000 or greater and a gigapixel image has a pixel size of 32768 x 32768.

Note that the interpolation used by hugin doesn't handle downsampling very well, so output images smaller than about half the size of the Optimal Size will show aliasing artefacts. If you want to create high quality small images, it is better to create an Optimal Size image in hugin and downsize it later in an image editor such as Gimp.

Crop

The crop settings allow just a portion of the panorama to be stitched, there are various reasons to do this:

  • When correcting perspective large areas of the panorama output will be empty anyway.
  • Large 'gigapixel' style panoramas can be stitched in sections then blended later.

The cropped-out areas are shown darkened in the Preview window.

The Fit Crop to Images button will automatically determine a crop that has a maximum number of pixels and no empty space. This is the same function as the Autocrop button in the Fast Preview window.

Output

Hugin can output 'normal' stitched images, exposure fused images or high dynamic range (HDR) images. The following options determine which kind of image is created, and allow keeping the intermediate images created during the process.

Normal

If Exposure corrected, low dynamic range is enabled then enblend is used for blending. In the final stitching process nona reprojects and distorts images to fit, enblend takes these images as individual TIFF files and merges them using sophisticated seam positioning and blending. Further enblend settings can be found in the hugin Preferences.

Enable Exposure corrected, low dynamic range under Remapped Images if you want to keep the intermediate images that enblend uses as input - For example modifying the alpha channel of these images and then blending manually is one technique for including and excluding people or objects that move between shots.

Exposure fusion

If Exposure fused from stacks is enabled then hugin will group the input images into exposure stacks by comparing positions, any images with more than 70 % overlap are grouped like this. Each of these bracketed exposure stacks will be exposure fused with enfuse and the results seam blended together into a panorama with enblend.

Note that for this to work, the scene has to be photographed multiple times using exposure bracketing and the EV exposure values set either manually in the Photos tab, automatically from EXIF data or by optimising exposure in the hugin Assistant tab or hugin Exposure tab.

Note also that unlike Normal and HDR merging options where images are exposure corrected as part of the remapping process, enfuse requires that each exposure layer is supplied uncorrected - Hugin takes care of this automatically and will not apply exposure correction in this case.

If Exposure fused from any arrangement is enabled then hugin will seam blend images with similar exposure with enblend and than it will exposure fuse them using enfuse. This variant is often much more successful than Exposure fused from stacks in two situations:

  • Where entire panoramas have been shot at each EV level consecutively rather than each shot bracketed, in this case it isn't guaranteed that shots will line up into the approximate stacks expected by the Exposure fused from stacks option.
  • When the panorama has been shot entirely on automatic exposure, in this situation it is useful to seam blend adjacent photos with small EV differences, but then exposure fuse larger EV differences - As effectively happens with this option.

Note that Hugin uses a default threshold of 0.5 EV exposure difference to determine which photos can be fused into each layer. This threshold can be modified on the Photos tab in the Expert mode (selecting group by Output layers).

Enable Blended layers of similar exposure, without exposure correction from Layers to keep exposure layers from the Exposure fused from any arrangement step, these are useful for manual Contrast Blending.

Enable No exposure correction, low dynamic range from Remapped Images to keep the intermediate images supplied to enblend and enfuse.

Normal Format can be in one several output file types:

  • TIFF, various compression options. 16bit and 8bit depth supported. None compression is supported by most other applications, LZW compression is common in Windows/Mac applications and Deflate compression is more common with Linux tools.
  • JPG, lossy compression suitable for web/email. Quality can vary from 0 (extremely low quality, small file size) and 100 (high quality, large file size). A typical quality setting for web/email would be between 70 and 80
  • PNG, lossless compression. 16bit and 8bit depth supported.

HDR merging

If High dynamic range is enabled then hugin will identify likely bracketed stacks of images, then create remapped HDR images which are then blended with enblend.

Note that like the Exposure fusion option above, this generally only makes sense if the scene has been photographed multiple times using exposure bracketing, and the EV exposure values optimised in the hugin Exposure tab.

Enable High dynamic range merged stacks from Combined stacks to keep copies of the remapped HDR images as supplied to enblend.

Enable High dynamic range from Remapped Images to keep copies of each image remapped in linear colour space before merging to HDR.

Click Stitch now! to generate output panoramas immediately. Selecting Save project and send to batch adds the current project to the Hugin Batch Processor stitching queue, note that the queue won't be processed unless this queue manager is running.

High dynamic range Format can be either:

  • floating-point TIFF, various compression options.
  • EXR, this is a high dynamic range format which is more compact than a high dynamic range TIFF.

Processing

nona is the default Remapper (stitching engine) supplied with hugin, normally there is no need to change this or any of the options below.

Set the Interpolator (i) to change the sampling interpolation. You probably won't notice much difference between the various options except that Nearest Neighbour is fast but with very low quality. The default of Poly3 (bicubic) is generally good for most purposes.

Cropped TIFF files are smaller and more efficient because unused parts of the image are not stored in the file. You should always save cropped images unless you need to open them in an image editor without Cropped TIFF support.

enfuse is the default for Exposure fusion, Options are similar to enblend.

The default HDR merger is hugin_hdrmerge.

enblend is the default Blender for use with hugin, normally there is no need to change this. Additional command-line Options can be set here or in the hugin Preferences for new projects.