Signature-based Remote Sensing Image Automatic Registration Study

The second China-Brazil Earth Resource Satellite (CBERS-02) was developed by China and Brazil, onboarding three kind of remote sensors: CCD, IRMSS and WFI. Since it was successfully launched in October 2003, it has produced a large amount of remote sensing image. But the image blurring and the large of image makes the registration which is necessary in the process of remote sensing image application difficult. In order to find or design a suitable scheme to complete the image registration effectively and efficiently, the following job have been done based on the CBERS02's CCD image.1. Based on the summary and compare of classical image registration algorithm, we conclude that the registration algorithm based on feature (RAF) has two aspects of advantage: (1) it is flexible; (2) it is high efficient because the computing based on feature only use a little part of the data. And so in this paper we will take advantage of this algorithm.2. The key part of RAF includes feature extraction and feature match. The image includes different kinds of feature, in this paper we focus on interesting point (IP) extraction. In order to find the most suitable IP extraction algorithm for the CBERS02's CCD image, two new criterions—the algorithm accuracy and relative repeatability based on classical IP is developed. Combined with the computing speed, the Plessey Corner Detector (PCD) based on correlation is a good choice based on quantitative compare. Because of the fault of PCD on localization and the blurring of CBERS02's CCD image, a new kind of feature—Area with Abundant Interest Points (AAIP) is developed in order to improve the localization. The reasonability and validity is proved by the experiments.3. In fact, the AAIP is area feature, and the area feature match becomes another research focus. Firstly some kinds of classical match algorithm based on area feature is discussed and compared, and some impossible improvement is developed. In order to find the most suitable algorithm, experiments are carried out to learn about the similarity's acuity, computing speed, anti-rotation and dependence on gray of different algorithm. Based on quantitative analysis of the result of the experiment we conclude that the algorithm based on mutual information is the best choice for our image.4. In order to advance the efficiency of the registration and reuse the feature extracted in the process of registration, we store the feature to form a feature database. When we carry out a new registration, firstly we select some feature from the database according to the latitude and longitude to reconstruct a reference image, and then start the registration. Because the feature exists before the registration, feature extraction which is the most time-consuming doesn't need to be carried out, and the efficiency of the algorithm is advanced. At the same time we extend the concept of the image registration from image-to-image to image-to-feature database. The experiment result proves that this way is effective, and the accuracy of the algorithm is about 1 pixel.In a word my dissertation demonstrates that the extraction of AAIP based on PCD algorithm and the feature match based on mutual information is suitable for CBERS02's CCD image; that the registration scheme based on feature database is feasible.