Aerial Camera Automatically Dimming Method Research Based On The FPGA

Aerial camera photographs from air to ground mostly, because of the complex ofshooting scene, the traditional dimming algorithm for the special scene such asbrighter or darker background or the existence of strong interference, will not be ableto achieve the correct exposure, sometimes it is prone to the phenomena of self excited, Aiming at this phenomenon, this article studies the domestic and foreigndevelopment status of in this light adjusting mechanism of the camera and in this field,and proposes the new method of dimming based on the scene division that verifyingthe algorithm that makes the aerial camera exposured well in the specialcircumstances by MATLAB simulation, it Improves aerial camera scene adaptability.Firstly this paper introduces the principle of the camera’s imaging and principleof CCD exposure, and the dimming method that is now available and shortage of that.Based on the study of existing methods, this paper presents a dimmingmethod based on the scene distinction. Process is as follows: first of all, I observe andstudy gray histogram of image, and classify the scene taking advantage ofcharacteristics of histogram distribution, the target area is determined for differentscenes. Secondly, I use the image segmentation threshold method determined byStatistics that get rid of the background and the interference points. At length,exposure time of camera that Entropy of information feedback controls camera isreckoned. In this process, it is related to image segmentation, object region extractionand other image processing techniques.This article establishes the experimental simulation environment of aerial cameraand PC machine and so on verifying the feasibility of the above method. The imagescaptured by the camera, and uploaded to the PC machine, and disposed by algorithmthrough the MATLAB, Calculated the target area (remove the background image orthe points after the interference) of gray average that is used to adjustable opticalfeedback, Finally, camera exposure time is controlled. By means of the method ofscene distinction make the target region more clearly, As in a dark background, the value of Gray target region Gray is124.39,but the value of taken by dimming of thetraditional method is254.65, Information entropy is increased by6.839; A brightbackground, the value of Gray target region Gray is51.7583,but the value of taken bydimming of the traditional method is24.7034, Information entropy is increased by0.8370.Finally, This article introduces the Related knowledge of FPGA, the algorithm ofthis article is modularized In the simulation environment of QUARTUS2.The mainalgorithm module is as follows: Image block、the histogram statistics、 P (s) graphstatistics and normal distribution fitting and so on. Finally, there is the simulationresults of a function module in this article. The simulation results show that thesimulation results of FPGA is in fact compatible with the simulation results ofMATLAB.