ImageJ Feature Extraction
Automatic finding of image features are very convenient for registering two images to align them in proper orientation. Two image plugins are implemented for extracting image features and are placed as menu items at: [Plugins > Feature Extraction > Extract SIFT Correspondences] and [Plugins > Feature Extraction > Extract MOPS Correspondences] For more details, see the linked page in Fiji wiki. For details about SIFT algorithm, see 2569. For more details about MOPS algorithm, see 2570.