为提高图像处理效果和处理速度，使处理后图像颜色与人眼视觉主观感受到的颜色保持一致，文章提出了一种改进的自动白平衡算法。该方法以灰度世界法和全反射理论法为基础，通过自动评估图像的色彩丰富性并确定相应的规则动态选取优势算法进行处理。设计实现了相应的FPGA处理模块，通过采用高效的并行流水线技术，充分考虑硬件模块内部潜在的并行度，确保系统的实时处理能力。文章算法的优势在于对图像的自适应性和计算的快速性。对不同场景图像，该方法产生不同的阈值参数，进而选取不同的优势算法，确保系统的自适应性；对高速视频图像，该方法建立了一个简化的优势算法选取规则，有利于FPGA硬件电路的实现，从而保证了计算的快速性。仿真试验表明，基于该算法设计实现的FPGA硬件处理系统，对不同的场景均取得较好的处理效果，针对分辨率为1920像元×1080像元的视频图像，达到了优于25帧/s的实时处理速度。该算法硬件电路开销少，实时性好，适应性强，能有效提高图像品质，具有广阔的应用前景。%In order to improve image processing quality and boost processing rate so that the processed imagesʹcolors become as same as the colors of human vision feeling, the paper proposes a kind of improved auto white balance method for CMOS camera image processing system. The proposed method is based on the gray world method and the perfect reflector method, and it can choose the proper method between the above two methods automatically by estimating the richness of color in the images. The corresponding FPGA processing modules are designed to implement the methods. Especially, the high-performance parallel pipelined technology and the inner potential parallel processing ability of the modules ensure the real-time processing ability of the complete camera system. The advantages of method mentioned in this article are adaptability and fast processing rate. This method has different threshold parameters for different scenes with appropriate algorithm for each scene to ensure adaptability. Also, it set up a simplified algorithm selecting rules for high speed video whose hardware is easier to implement on FPGA which can guarantee faster processing rate. The simulations and the experiments show that the FPGA system implemented the proposed method can achieve the good processing performance in different sceneries and it can process the 1920×1080 image resolution videos at a speed of 25 fps. This method with high real-time performance and strong adaptability and less cost on hardware as well would have wide prospect on imaging processing field.
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