Research And Design Of Color Digital Image White Balance System Based On FPGA

The innovation of science and technology promotes the rapid development of the field of machine vision.The image system integrating acquisition,processing and industrial control has become the focus of the future development of industrial machine vision.Compared with the traditional gray-scale camera to recognize the shape of the object,the color camera is more similar to the human eye.To recognize the color of the object.Aiming at the poor color quality of existing industrial cameras and the complex update procedures in the industrial application environment,a color image white balance system is designed.The system uses FPGA as the core to collect the color image of the image sensor,and realizes the white balance algorithm to correct the non-standard light source.The color cast image and the processed color image are transmitted to the host computer display and industrial control through Gigabit Ethernet,and the Ethernet online update function is designed in the system to improve the convenience of program update.In order to ensure the color quality of the image transmitted by the system,based on the selection of the main components of the system,the Bayer image collected by the image sensor is sequentially corrected for temperature drift to reduce the temperature influence of the external industrial environment,and the full resolution fixed-point dead pixel correction eliminates the inherent image sensor Three image preprocessing designs of defects and Bayer to RGB images ensure the correctness of the system data.After comparing the two classic white balance algorithms of gray world and perfect reflection,under the assumption that the perfect reflection method has a small amount of calculation and the white balance is invalid in the exposure environment,a perfect reflection white balance algorithm based on the dark channel theory is designed,which passes The screening of reference points increases the applicability to the exposure environment while ensuring the quality of the white balance.Using the Gigabit Ethernet channel and FPGA multiple system architecture in the image transmission process,complete the online update function and logic design of the Gigabit Ethernet system to reduce the complexity of disassembly and assembly during the system update process.Finally,a test platform was built to test the stability of the system and the online update function,and evaluate the color values of the images of the three common scenes after being processed by the white balance module.The processed images have an evaluation value of about 1,for exposure Compared with the perfect reflection method,the color reproduction degree in the environment is 3 times that of the original image.It proves that the color image system is stable and reliable,while improving the color reproduction rate of the color image.