Lateral Chromatic Aberration - JAI LQ-201CL User Manual

Operating procedure for individual R, ,B and NIR channel shading correction:
1. Before making adjustment, approximately 30 minutes of warm up is required.
2. Make sure the output signal is not saturated (<80% of full output is recommended)
3. Set command PGC=2 and SDC=2.
4. Set command SDR to 1 to initiate shading correction.
5. If desired, set command PGR to 0 to activate flat-field (pixel gain) correction to
correct for pixel response non-uniformity.
6. Again set SDR=1 after running the flat-field (pixel gain) correction
Please note that before adjusting the shading, the white balance must be adjusted.

6.2.11 Lateral chromatic aberration

This function compensates for lateral chromatic aberration of lenses. Lateral chromatic aberration
causes different line lengths for the R, G, B and NIR rays at the focal point. This function enables
compensation data for up to three lenses to be stored. The compensation data specifies how many
pixels the R, B and NIR channels should be stretched or shortened to match the line length of the G
channel which is the reference. The range of correction is minus three pixels to plus three pixels.
In order to realize this function, the LQ-201CL uses an FIR (finite impulse response) filter for R, B
and NIR channels. The filter's response is determined by a set of 7 types of filter coefficients. The
2048 pixels that make up a line are divided in 16 blocks, with each block having 128 pixels.
To compensate lateral chromatic aberration, the 7 types of coefficients are set for each block.
In the factory, a default set of 112 data elements (7 types x 16 blocks) are calculated and stored.
Pixel number in each block: 128 pixels
Note: Restrictions for this function
In order to adjust properly lateral chromatic aberration, the difference between G and R or B or NIR
on right and left sides should be equal. Otherwise, the compensation may not be properly executed.
The following screen is used for creating up to three user-defined sets of lateral chromatic
aberration data in the camera control tool.
LQ-201CL
23
2048th Pixel