Flat-field correction is also known asLight-field correction, grayscale correction, or speckle correction is an image-processing technique used to calibrate image sensors or cameras. It aims to eliminate brightness and color non-uniformities in images caused by uneven sensor responses, lighting variations, or other factors.Flat-field correction can improve image quality, making the brightness more uniform across different regions., reducing artifacts, noise, and other impairments in the image.

（1）To address issues such as unevenbrightness and vertical lines appearing in the image, it is necessary to prepare...Large white paper (the white paper must be free of creases, dirt, and other blemishes) covers the entire field of view.By adjusting the aperture and setting the exposure, the image is...The grayscale values in the central region remain between 120 and 180.（It is best to match the grayscale values of the detection object itself; the grayscale difference between the brightest and darkest pixels should not exceed 8 times.

（2）willThe lens is out of focus until the vertical lines on the white paper are no longer visible.This blurs the overall image and reduces the impact of features on the algorithm.

（3）Flat-field correction operation

① Select PRNUC Correction from the Shading Selector (as indicated by number 1 in the figure);

②Activate Shading. Click Execute (wait 2-3 seconds before proceeding to the next step) (as indicated by number 2 in the figure);

③ PRNUC Enable: Click to enable (as indicated by number 3 in the figure)

（4）You can obtain the image with uniform grayscale as shown in the figure.