What are the common sources of errors in CCD industrial cameras?

  Error sources of CCD industrial cameras : Errors are mainly caused by the distortion of the optical lens, mechanical errors and the "analog/digital conversion" of the video signal. The resulting errors are called optical errors, mechanical errors and electrical errors respectively.
1. Optical error: Also called optical distortion, it refers to the point error in which the image point deviates from its correct imaging position caused by errors in the design, production and assembly of the camera objective lens system. Optical distortion includes two types of radial distortion (RadialDistortion) and centrifugal distortion (DecentringDistortion). Radial distortion causes the imaging point to deviate from its accurate position along the radial direction; while centrifugal distortion is caused by the inconsistency between the optical center and the geometric center of the lens. Error, which causes the constellation point to deviate from its correct position both along the radial direction and perpendicular to the radial direction.
2. Mechanical error: The error occurs in the step of converting the image taken by the optical lens into the digital array image. This error is caused by the following two factors: ①. The scanning array is not parallel to the optical image, causing the digital image to
be The optical image is rotated;
②. The size of each array element is different, resulting in uneven deformation.
3. Electrical errors: mainly include horizontal synchronization error, field synchronization error and sampling error. Horizontal synchronization error refers to the misalignment phenomenon caused by the synchronization signal at the beginning of each line of the image when the video signal is converted; field synchronization error refers to the odd-numbered lines of the image and Misalignment between even-numbered lines; sampling error refers to the sampling interval error caused by unstable clock frequency. The overall performance of the linear array CCD camera in the system is the impact of optical distortion on the imaging geometric model. The impact of optical distortion is nonlinear, non-
linear symmetrical. A certain algorithm is usually used to correct and resample, but the results cannot meet the system requirements because (1) it exceeds time control; (2) it is not conducive to the overall expansion of the system.
Solution: When the system performs difference calculations on the detected image and the template image, they are both placed under the same conditions. The impact of optical distortion on both sides is the same. You can ignore the impact of optical distortion on the detection results. , this method is feasible after testing.