The Design Of Correction Method Of The Led Display Brightness Based On CCD Camera

The LED display contains thousands of leds.According to the industrial classification standard of LED manufacturers,the allowed brightness error is 20%-40% and the chroma error is 5nm in the same batch.However, for the hundreds or thousands of times magnification video source LED dispaly, the brightness difference of the human eye can identify is 1% -2% and the color difference is 1-2nm;on the other hand, in the process of LED display using, different degrees of the attenuation of light and color shift may happen, which appears the phenomenon of uneven between pixels display and the decreased of the overall brightness of LED screen, so that the affect and the using life of the LED display will be decreased.According to the above problems,this paper discussed the implement flow of spot-spot luminance ununiformity correction techoniques with CCD camera based on the principle of LED display control and correction.The technology is that the CCD camera collects the data information of each pixel in the LED display quickly and accurately and then through a series of algorithms about lamp positioning and brightness calculation to calculate the corresponding correction coefficient matrix of pixels, and then adjusts the LED brightness values through the PWM pulse width modulation so as to achieve display uniformity correction.So that we can adjust the brightness of the led pixel according to the matrix to achieve display consistency of correction.The key technologies of this paper are camera focusing ,image point positioning,brightness calculating and coefficient correction . To ensure the clarity of the image, the paper uses the PCA method based automatic focusing technology,the experimental results show that the method can obtain good focusing effect and increase the correctness of image processing and analysis of follow-up.Generally speaking,the technology can be implemented point by point in the process of correction of LED brightness,so it can alleviate the LED light uniformity to some extent, improve the LED screen display and extend the life of the display.