Realization Of Auto White Balance Algorithm Based On FPGA

Automatic white balance technology is widely used in the field of imageacquisition and processing to meet people’s demand for information． There aremany existing auto white balance algorithms， and they are different incomputational complexity， the white balance processing effect and hardwareadaptation and so on． Although these algorithms can get satisfactory colorrestoration, most of them are based on certain assumptions．In practice，because ofso many restrictions，its practicality is very poor．Especially processing the imagewith large blocks of a single color is difficult．After studying the existing automaticwhite balance algorithm，the author makes full use of the FPGA’s advantages，suchas：high performance，low power consumption，high speed，a flexible and extensibledesign features，and puts non-damaging the picture quality as a precondition，hasimproved auto white balance algorithms based on color temperature estimation，andverified the validity of the algorithm on a DE2-115development boards．First，the paper introduces the basic knowledge of color images，including：color temperature，color space，color constancy，and image processing．Thendescribe the basics of FPGA technology and programming language in detail．Second，researching the existing gray world white balance algorithms，thenimproving the algorithm that based on color temperature estimation．Since the grayworld white balance algorithm is based on certain assumptions， when theassumption is not true (especially when there are large blocks of color in theimage)， the algorithm almost fail．In order to solve the problem， through theresearch of the calculation process of the algorithm，the author improved auto whitebalance algorithms based on color temperature estimation．Finally，using the FPGA to design the auto white balance algorithm which isbased on color temperature estimation． Use the Quartus II10.1software andVerilog hardware description language to design the algorithm．After the process of time analysis，simulation and comprehensive，the design will be downloading to theFPGA chips on DE2-115development boards at last．Through the compare of experiments，it has been proved that，in the samecomputational complexity and non-destroying the picture quality， the improvedwhite balance algorithm which is based on color temperature estimation has gaineda better performance over the gray world algorithm in dealing with colorfulimages，with better color balance as a result．...