Registration is used in precision agriculture to adjust near-infrared aerial photographs and visible crop spectra to analyze crop growth and development. Vegetation indices can be calculated from the registered images. It is therefore necessary to study and analyze the most popular techniques for detecting points of interest. The points of interest found are used as reference in the images of both spectra. Thus, a comparative study of pasture crop images with four of the most popular point of interest detection techniques (Harris, SIFT, SURF and ORB) is presented here.