New Image Synthesis Based On Image Alignment And Color Transfer

High dynamic range image, whose pixel value is proportional to the true radiance, can represent a wide range of scene's luminance. Based on the image alignment and fusion technique, a method for fusing multiple photographs into a high dynamic range image is studied. The photographs are taken with varying exposures towards the same scene. The technique of color transfer synthesizes the color information of reference image and the shape information of target image to construct a novel image. A method for color transfer between two color images is studied.A fast and simple method for aligning images with different exposures is studied. Firstly, according to the histograms of the image-sequence, the median threshold images are computed. Then their image pyramids are constructed using multi-scale technique. Move and compare the image pyramids from low level to high level to complete shift-alignment of the images. Based on the shift-alignment, obtain the pixels, which are on the maximal circumferences of the images, then rotate and compare them. Thus rotation-alignment of the images can be achieved.Based on the results of shift-alignment and rotation-alignment, a method for fusing multiple images into a high dynamic range image is studied. At first, sample the pixels from the aligned image-sequence at random. Construct and solve the solution system by least squares principle to recover the response curves of imaging process. Then smooth the curves with B-spline function, and acquire the mapping relationship between pixel values and exposures. At last, the relative radiance values are computed, and a high dynamic range image can be constructed from the multiple common images.A simple method for color transfer, by which target image can acquire the color information of reference image, is studied. Firstly, put both the reference image and the target image to an orthogonal color space. Then compute the color distribution of the two images. Using the special transfer algorithm, transfer the reference image's color statistical values to the target image. The method can be applied to high dynamic range images as well as common images.A system of high dynamic range image composition and color transfer has been exploited based on the above-mentioned methods. It can realize image alignment, high dynamic range image composition and color transfer. The experimental results show that the system is satisfactory.