Image pre-processing on the frame grabber is a central intermediate step in the image processing process from image acquisition with the camera to processing in the frame grabber and output of results in the host PC. It ensures that image data is optimized for the respective application, transferred securely and without loss of individual images to the subsequent processing to guarantee smooth operation. The aim of image pre-processing is to prepare the data in order to simplify further processing steps and to relieve the load from processing in the host PC.
This includes a better visualization of the images in order to emphasize certain properties or structures that are too weakly pronounced or that are important for further processing (delimiting areas, segmentation and feature extraction). This is usually based on the entire raw image. This also includes the automatic selection of image areas (Region of Interest, ROI) according to image content and the JPEG image compression - more about this later.
The processing steps used in pre-processing always depend on the existing image quality of the camera sensor. The steps are executed on the FPGA processor of the frame grabber, and also on the other vision hardware such as the camera itself, the vision sensor or embedded system. On these vision devices, VisualApplets, the easy-to-use graphical development environment can be used to implement extensive pre-processing as well as a complete image processing solution on the FPGA, thus realizing a real-time capable system.