Research On Image Mosaic Algorithm

Image mosaic is a technology that carries on the spatial matching to a series of image which are overlapped with each other, and finally builds a seamless and high quality image which has high resolution and big eyeshot. Image mosaic has widely applications in the fields of photogrammetry, computer vision, remote sensing image processing, medical image analysis, computer graphic and so on.Generally speaking, the image mosaic process consists of the following steps. image acquisition, image registration, image fusion. Image registration is the important foundation of image mosaic.This article has studied two kind of image registration algorithm. feature-based image registration and FFT- based image registration algorithm.Through researching the feature-based method, a robust image registration method is proposed. Firstly, corners are extracted using improved Harris operator which improves the precision and speed. Then, a normalized cross correlation and a kind of match method with bidirectional greatest correlative coefficient are used to extract the initial feature point pairs, and then the false feature point pairs are rejected by a Random Sample Consensus algorithm.Finally, the correct matching feature point pairs are used to realize the image registration. It has better registration results under a variety of conditions such as different light, bigger rotation and repetitive texture. The experiment results indicate this algorithm has good effect in image registration, high accurate rate, strong robustness, higher use value.FFT-based phase correlation image registration algorithm is often used. Its theory is simple, realizes easily, resists noise, but time is long and difficult to process the rotation and zooming. This article has studied FFT-based image registration method, the polar coordinate transformation is introduced in order to make the rotation and zooming factor transform into the translation form, greatly reduce the computation. The experimental result has indicated this method feasibility and validity.If without image fusion technology, the mosaic image will have the obvious seam, therefore must seek a good fusion method to eliminate this kind of seam. This article has proposed one kind of improvement gradually enters gradually leaves fusion method to realize the image mosaic. The algorithm has obtained the satisfactory blending effect.