8.Features
© 2023 China Daheng Group, Inc. Beijing Image Vision Technology Branch 114
[FFCFlashLoad] Load the FFC coefficient value which is set in the FFCCoefficient to the camera from
Flash.
[FFCExpectedGrayValueEnable] OFF: enabled. On: enable.
[FFCExpectedGray] The expected average gray value after setting FFC, which is effective when the
FFCExpectedGrayValueEnable is On.
[FFCROIWidth] Set the width of FFC region of interest.
[FFCROIHeight] Set the height of FFC region of interest.
[FFCROIOffsetX] Set the horizontal offset of FFC region of interest.
[FFCROIOffsetY] Set the vertical offset of FFC region of interest.
After setting FFC ROI (Region of Interest), the FFC parameters are still calibrated by full resolution image.
However, the calculation of the FFC correction coefficient is based on the brightest area of ROI, which
means that the effect of FFC is to correct the brightness of the entire image to the brightest area of ROI,
rather than the brightest area of the entire image.
It is recommended to first determine the aperture of the lens and the camera gain before calculating FFC
coefficient. In the following cases, the coefficient need to be repeated:
Lens replacement
When there is a high requirement for FFC coefficient accuracy (eg: correct the Inconsistency of the
pixels), it is recommended to recalculate the FFC coefficient after modifying the camera gain.
Note:
FFC calibration needs a long time, when the FFCGenerateStatus is “WaitImaging”, it is forbidden to
execute other operations, because the camera is waiting for images to calculate FFC coefficient
Please calibrate FFC in full screen mode
Use default value for non-essential steps
It is recommended to aim at the white paper or flat light source (ensuring consistent light input in
different areas of the sensor) and adjust the distance between the camera and the white paper/flat
light source to fill the entire field of view
Do not overexpose the image. It is recommended that the grayscale value of the brightest area in the
bright field be less than 250
The image should not be too dark, and the grayscale value of the darkest area in the bright field is
recommended to be greater than 20
It is recommended to control the bright field grayscale value by adjusting the exposure time or light
source, rather than the aperture
