Study On The Algorithm Of The Depth Image’s Acquiring Based On Laser Speckle

Depth image means the value of pixels in the image is the distance between the object and camera.It can distinguish the foreground and background effectively,so it is more efficient for the target recognition.This paper studied the principle of depth camera and the cameras that can reach mass production.At present there are already the depth camera that can detect a wide range,contains motion scene in real time,and the cost is low abroad.Due to technical blockade,similar equipment’s performance is relatively poor domestic.In order to improve the performance,this paper studied the method of acquiring of depth image based on laser speckle.Firstly,this paper studied the principle,system and optical grating of speckle,analyzed the self-correlation and cross-correlation of speckle through experiment.Then this paper studied the possibility of the speckle image as a space structured light to detect the depth.Secondly,this paper studied the principle of the depth image’s acquiring through space structured light,analyzed the relationship between depth image and speckle image,derived the formula of depth image.This paper proposed an efficient and easy block matching method,which can acquire depth image quickly,narrated the process of acquiring the whole image’s depth using the way of exclusive or block matching detailedly.Thirdly,this paper optimized the arithmetic of the depth image acquiring,both on speed and accuracy.In terms of speed,this paper studied the best choice of size of matching block,proposed a variable searching block size searching method,proposed a fast matching strategy,to reduce the calculation greatly.In terms of accuracy,this paper studied the influence of speckle image system’s parameter and introduce the way to improve the accuracy through adjust the speckle image system’s parameter.Then this paper proposed a method of improving the accuracy,an interpolation method of crosswise offset interpolation to improve the depth camera’s resolution.Finally,the experimental results show that the block matching this paper proposed,with the speckle image system’s parameter showed in chapter three of this paper,depth accuracy can reach 1cm in the distance of 50 cm and 5cm in the 200 cm.This can satisfy the detection requirements for most scenes.In terms of speed,put the speckle images to personal computer with 3.60 Ghz dual-core processor CPU and 4GB RAM configuration,and then do experiment on the PC,we can get a 1280 * 720 pixels depth image within 0.5 seconds.