A Panorama Mosaic System Based On YHFT-DSP And Pan-Tilt-Zoom Camera

Image technology has very important use in so many military areas such as precise attack,enemy detect,supervision of battlefield and evaluation of battle etc.But,detectors at present,like optical ones,night-vision ones or infrared-thermograph ones,can't take panoramas at high resolution ratio because of the limited vision angle.To overcome this problem,we can use a serial of images taken by a pan-tilt-zoom Camera to form high resolution ratio panorama image cheaply through image mosaic technology,to get the whole image view information from the battlefield.Aiming at designing a kind of flexible and high-efficient panorama-making set using YHFT-DSP image platform and a focus-adjustable pan-tilt camera,this paper have solved two key problems,that is precise control of pan-tilt camera by YHFT-DSP is carried out,and image mosaic is realized on the YHFT-DSP platform.Research done and innovations made in this paper is as follows:1.The module for pan-tilt control is programmed to realize precise control of pan-tilt camera movement such as power on,power off,zoom,pan and tilt.etc.2.Suitably Adapting the MORAVEC algorithm for feature points detect.According to the rule that multiplication on DSPs takes obviously more CPU cycles than modulus,we adapt the algorithm by replace sum of square gradient with sum of modulus gradient from the four direction.At the same time,we choose the most obvious feature in a certain area?in this paper,we set 5×5 area?in order to avoid more than one feature point detected in that area.Through test,the adapted algorithm has a performance improvement by about 1.18 times,and the quantity of features detected changes little.3.Before the first feature matching,we forecast the area that may exist matches firstly,then we match the feature points,both from image waiting for mosaic to destination image and from destination image to image waiting for mosaic,by using the correlation coefficient.Through this method we can reduce the finding area to W₁×H₁/W×H of the primary?where W is width of the image,H is height of the image,W₁ and H₁ is the width and height of the area for finding the match point you defined?,and the time and calculation needed for matches finding reduces greatly.When calculate the equation about parameters of transform module,we resolve the equations'matrix by Doolittle,to avoid the huge number that exceeds the limitation of DSP and making the result not so exactly.4.Calculate the transform module from the destination image to the image waiting for matching,then the image waiting for matching is carried to the target image by backward double-linear insertion,at the same time,using smoothly-in smoothly-out method for image fusion.5.Based on YHFT-DSP Image Board,a panorama mosaic system is carried out.From test,we find the system can control the pan-tilt camera precisely,collect and save image correctly,and mosaic images accurately.The comprehensive performance of the system meets the demand of the design.