Image Registration and Mosaicking Based on the Criterion of Four Collinear Points
In order to avoid the influence caused by mismatching, improve the stitching accuracy, image registration based on refined feature points has been proposed. First, Harris corner detection is utilized to extract the feature points. Then the collinear points set have been selected from all of the feature points. Select the number of collinear points which are greater than or equal to 4. The collinear points from two images have been estimated by Cross-Ratio criterion. If the value of Cross-Ratio meets a certain threshold, these collinear points will be retained. 4 groups of points which are extracted from collinear points set will be used to calculate equation solution of projection transformation. Finally, fusion method combining optimal seam with feathering has been used to stitch images. An increase in the number of mismatching will cause a decline of image registration precision. There is a fall of 14.7% accuracy when one group of mismatching appears. There is a fall of 36% accuracy when three group of mismatching appears. However, the accuracy of our method has almost been unaffected. The collinear points extracted by Cross-Ratio rule are a good way to avoid the interference of mismatching. The precision can be guaranteed in the experimental process.