Abstract: The disclosure discloses a method and device for locating an image edge in a natural background. The method comprises: extracting a central color feature serving as a comparison standard for an image located in a natural background; comparing with the central color feature, and extracting multiple candidate points for each edge of the image according to a comparison result; grouping the multiple candidate points corresponding to the edge according to a distance and/or a direction, so as to obtain multiple candidate point groups; fitting a corresponding fit line by using a candidate point in each candidate point group; and selecting a fit line close to most candidate points of the edge, and locating the fit line as the edge.

Abstract: Disclosed are matching image searching method, image searching method, image matching method and devices thereof. The matching image searching method comprises: extracting local features from a to-be-queried image; matching local features of each images in an image database with the local features of the to-be-queried image, determining a matching proportion thereof; disposing images of which the matching proportion larger than or equal to a first proportion threshold value in the image database into an image matching result; and for images having matching proportion less than the first proportion threshold value and larger than a second proportion threshold value in the database, calculating hamming distance between perceptual hashing value of the images and a perceptual hashing value of the to-be-queried image, and disposing images having hamming distances less than a set first distance threshold into the image matching result.