Digital Image Processing Technology Apply To Evidence Of Audio-visual Materials

Evidence of audio-visual materials is in the No.7 individual catalog of Criminal procedure law of the People's Republic of China. The evidence is useful to detective and judge of criminal cases efficiently, and also challenging the technology of the criminal analyzing. As the sound and video evidence is multiplicity and easy to falsify, It is very important to determine the truth of the evidence by judicial expert. Digital image processing technology is usually used by judicial expert to determining the evidence, the basic ways to determine the image is originally, authenticity and other related verifying. By developing and applying the digital image process technology in Evidence of audio-visual materials, it enforces the police power of that state within a defined legal or territorial area of responsibility, to detective criminal, protect the people and our society.This article introduce the sound and video evidence and digital image processing technology be used in the China and overseas and also analyzing the characteristic, details in digital image processing technology. Moreover, digital image processing technology which apply in three real cases of sound and video evidence. First, by using image CIE Lab space segmentation, to determining whether the image by artificial made. Furthermore, to apply the phong light model and fitting ellipse equation to calculate the camera position in the image. To compare the sampling of R,G, B channels to calculate linear relativity between the objectives and the image, the objective and the objective in constructing gray histogram. By the case studies, the result to solve the problems of similarity in the images of objective in reflection and its refraction, in examining of objective and its corresponding relation, and in the materials of clothes which is valuable to the judicial expert to solve the problems in Evidence of audio-visual materials.