Glossary

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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

Chromatic aberration

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

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

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.

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

J

JPEG Joint Photographic Experts Group wiedely used Image format

K

L

Landscape Image orientation with the longer side in horizontal direction.

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

M

N

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.

Nadir The point directly below

O

P

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

R

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.

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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