Researches On Image Mosaic

Image mosaics technology is an important research branch of digital image processing. It carries on the spatial matching to a series of image overlapped with each other, and finally builds a seamless image with higher resolution and bigger eyeshot compared with a single image. Moreover, image mosaics technology can be used to construct the large field of view and high-resolution image, and widely applied to virtual reality, medical image processing, remote sensing and military affairs.The thesis first introduces the background of image mosaics technology with great potential, and then demonstrates its characteristics and present research directions. In the second chapter, the author discusses the basic steps of image mosaic. Furthermore, the two pivotal methods of image mosaic, which are the image registration methods and images fusion methods, are introduced respectively. In the third and forth chapter, the thesis analyzes several traditional algorithms, such as the template matching and phase correlation algorithm. Moreover, in order to improve the above-mentioned algorithms, the modified methods are proposed backwards.Specifically, in the traditional template matching algorithm, light intensity always interferes with image mosaic. A modified template matching algorithm in the Lab color space is proposed to solve the problem. In the Lab color space, it is so convenient to divide the light intensity from pixels that we just need calculate the difference between color values a and b. The results show that the proposed method can significantly attenuate the interferences due to the light intensity. On the other hand, random points within the threshold are selected and calculated in a quite small region, rather than the whole region, which largely reduces the complexity and increases the calculation speed.To further reduce the interference from the light intensity, a contour phase correlation algorithm has been adopted. After picking up the binary image, a contour phase correlation is calculated to achieve the desired image. For another, when finding the maximum peak of the Dirac function array, we propose an iterative method with higher accuracy. The results of the experiments have significance for application in image mosaics technology.