Difference between revisions of "Glossary"

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== O ==
 
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'''[[Optical axis]]]''' The middle longitudinal axis of an optical system.
  
 
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== P ==

Revision as of 15:01, 17 December 2005

Please add the entry alphabetically to the list. A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


A

Aliasing - less than optimal resampling that causes "jaggies" and Moire effects.

Alpha channel - an image channel containing a mask or selection.

Angle of View The angle in degrees that a projection covers.

Aspect Ratio - the ratio (proportion) between height and width of an image.

B

Banding Visible steps in smooth gradients.

Barrel distortion A distortion produced by the lens itself which causes straight lines to be bent outwards.

C

CCD A type of image sensor used in digital cameras.

Chromatic aberration

Contrast Blending A technique to blend several exposure bracketed images in one image

Cubic Projection A subcase of the Rectilinear Projection used as the input source projection for some fully spherical panorama viewers.

Cylindrical panorama A panoramic image in Cylindrical Projection

Cylindrical Projection A projection capable of mapping 360 degrees horizontally by roughly 120 degrees vertically with acceptable distortion.

D

Depth of Field The distance in front of and behind the focus distance where the image blur is not recognizable.

Dynamic range The ratio in brightness of the brightest highlight to the darkest shadow that are accurately captured in a scene.

E

Entrance Pupil The special point that you have to rotate your camera around, to avoid parallax errors. Commonly referred to as the Nodal Point, which see for more information.

Equirectangular Projection A projection capable of mapping the entire sphere to a rectangle with 2:1 aspect ratio.

EXIF Exchangeable Image File Format. EXIF data allows camera, lens, exposure information, image description, copyright, etc. to be embedded in an image file.

F

Field of View The angle in degrees that a projection covers.

Fisheye Projection A projection where the distance from the centre of the image to a point is proportional to the equivalent spatial angle.

FJPG is a JPEG flavor that supports display of high dynamic range images for PTViewer 3.x introduced by Helmut Dersch.

Focal Length the physical property of a lens which together with the sensor size determines the Field of View

G

Gamma The relation between pixel values and visible brightness.

GIF Graphics Interchange Format. An Image format introduced by compuserve.

H

Halo Bright or dark areas along hard contrast edges introduced by certain image manipulations.

HDR High Dynamic Range

HDR compression The compression of the Dynamic Range in order to be displayed on a low dynamic range device like monitor or printer.

Hyperfocal distance The distance on which you have to focus your lens if you want the Depth of Field to stretch to infinity.

I

Interpolation A mathematical way to estimate a value in beetween two values. In image processing: The pixel color and brightness in between two pixels.

J

JAR A file format for distributing Java software

Java A programming language, program execution environment and executable program format

JPEG Joint Photographic Experts Group wiedely used Image format

K

L

Landscape Image orientation with the longer side in horizontal direction.

Lens correction model A mathematical model that allows the correction of some lens distortions

Lens distortion A distortion produced by the lens itself which causes straight lines to be bent in some way.

M

N

Nadir The point directly below

Nodal Point The special point that you have to rotate your camera around, to avoid parallax. Also called "entrance pupil". Click the term for more info.

O

Optical axis] The middle longitudinal axis of an optical system.

P

Panorama An image of a very wide or even surround scene or with a typical Aspect Ratio

Parallax Foreground shift in two images shot from the same scene but from different points

Philosphere A way to map a spherical panorama on the outside of an approximated sphere invented by Philo

Pincushion distortion A lens distortion which causes straight lines outside the image center to be bent inwards (like a pincushion).

Pitch Angle up-and-down (above and below horizon). See also "Roll" and "Yaw".

Pincushion distortion A distortion produced by the lens itself which causes straight lines to be bent inwards.

PNG Portable Network Graphics Image format

Portrait Image orientation with the longer side in vertical direction.

Projections Different possibilities to get a two-dimensional image of the three-dimensional world around us.

PSD Photoshop Document format. A proprietary Image format used by Adobe Photoshop

PTOptimizer Panorama tools image position and correction parameters optimizer. Script driven.

PTStitcher Main panorama tools stitcher application. Script driven.

PTV PTViewer Image format, supported by PTViewer version 2.8 from Fulvio Senore

Q

Quicktime Apples multimedia technologie.

QTVR QuickTime Virtual Reality A subset of the functionality of Apple Quicktime

R

RAW A group of some hundred proprietary image formats containg unprocessed sensor data from digital cameras.

Rectilinear Projection A projection in which every straight line in the world stays straight in the image.

Roll Rotation angle around the lens axis. See also "Pitch" and "Yaw".

S

Spherical is a panorama format that can contain the whole sphere around the viewer.

T

TIFF Tagged Image File Format. A widely used Image format for storage and exchange of image files.

Tone mapping A way to map pixel values in order to be viewed with a device with lower dynamic range as the original image.

U

V

Vignetting Light fall-off in the corners of images

W

Wavy distortion A distortion produced by the lens itself which causes straight lines to be bent in waves.

X

Y

Yaw Panning angle, left-and-right. See also "Pitch" and "Roll".

Z

Zenith The point directly above.

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others