Design And Implementation On Image Signal Process Based On Bayer Pattern Interpolation

In information age,human demands for more amount of information,while the information has changed to more complexly.Sometimes it is hard to describe information by word.It is better for human to record information by image.Today is the age of Internet, A variety of images appear in We Chat,C ircle of friends,weibo and other Internet tools.For transmiting true image,it must post the image closing to trueth.Therefore,each big mobile phones, tablet manufacturers continuous improve the technology and design on camera.Nowadays,the manufacturers of digital camera almost use CCD or CMOS image sensor,and cover a layer of Color Filter Array,named CFA. As the name implies,the function of it is filtering.Through filtering,there is many pixels on a frame of image.It is only one physical color(Green,Blue or Red) on each pixel.It's not a complete image.To obtain a colorful image,it must acquire the other two physical colors by the interpolation algorithm.It is usually called as the process of color interpolation.Bayer interpolation algorithm is the most widely way on it.On the front camera,the image is captured by CCD or CMOS image sensor.After filtering,it is an unprocessed image,called RAW image.The RAW image is shooting by camera.Because of unprocessed,it doesn't cause information loss.But the raw image has many disadvantages.It stores all information of the image,so that the file is very large,the need of time is very long and it need more storage.It cause serious impact on the storage and transmit on image.Besides,it needs professional software to open the RAW file.If there is not suitable software on computer,we can't open the image.It is possible if the computer is updating so that the software can't install.The software as we know,need much time to open a image.In conclusion,it is not convenient for general user to use RAW file image.In this paper,it is changed RAW file to RGB file on the base of Bayer interpolation algorithm.There is only one physical color on RAW file while there are three physical colors on RGB file.Through designing a Bayer interpolation algorithm,it makes the obtained RGB file more close to true image.For improving each frame image,it uses the values of 7x7 grid to compute the other two physical color on a pixel.To inhence the transmit speed,it is designed by the water type design.Considered the clock frequency,it is limited the numbers of addition and subtraction on each clock,the number is less than or equal to 3.For the multiplication or division on the compute,it is limited the multiplier o r divisor as constant so that the compute can change to addition or subtraction.It is little impact on image distortion.This design is degsined by Verilog HDL language,and simulated on 24 Mhz by NCverilog.It is verified the design result through comparing simulated result with result by hand,and the result is correct.