Shading Correction; Offset Shading Correction; Gain Shading Correction - Basler Racer User Manual

AW00118508000

8.9 Shading Correction

Two types of shading correction are available on the camera, offset shading correction and gain
shading correction. You can set the camera to only perform offset shading correction, to only
perform gain shading correction, or to perform both types of shading correction.
8.9.1

Offset Shading Correction

When a line scan camera with a digital sensor captures a line in complete darkness, all of the pixel
values in the line should be near zero and they should be equal. In practice, slight variations in the
performance of the pixels in the sensor will cause some variation in the pixel values output from the
camera when the camera is capturing lines in darkness. Offset shading correction (also known as
dark signal non-uniformity (DSNU) correction) corrects for this type of variation.
Offset shading correction works by adding an individual gray value to each pixel value in the
acquired lines. The gray values used for correction are included in a "shading file", commonly also
referred to as a "shading set".
In order to use offset shading correction, the user must enable offset shading correction and
activate the related defaultshading file or the previously created usershading file (see below).
8.9.2

Gain Shading Correction

When a line scan camera with a digital sensor captures a line with the camera viewing a uniform
light-colored target in bright light, all of the pixel values in the line should be near their maximum
gray value and they should be equal. In practice, slight variations in the performance of the pixels
in the sensor, variations in the optics, and variations in the lighting will cause some variation in the
pixel values output from the camera. Gain shading correction (also known as photo response non-
uniformity (PRNU) correction) corrects for this type of variation.
Gain shading correction works by applying an individual multiplier to each pixel value in the
acquired lines. The multipliers used for correction are included in a "shading file", commonly also
referred to as a "shading set". In order to use gain shading correction, the user must enable gain
shading correction and activate the related defaultshading file or the previously created
usershading file (see below).
Basler racer Camera Link
Features
127