Patent ID: 7742634
Filing Date: 2010-06-22
Classification: G06K,G06T

Abstract:
1. A method for, with a gray image of a predetermined size as a processing object, extracting the position of an object corresponding to a preliminarily specified model from the processing object image, wherein after a step A of extracting an edge pixel from an edge of a model image obtained by photographing the model; a step B of retrieving a density gradient direction of each extracted edge pixel based on each edge pixel so as to extract an edge position in the unit of sub-pixel; and a step C of registering the extraction position and the density gradient direction used for extraction of an edge pixel whose edge position is extracted in the step B with correspondence to the edge pixel are carried out preliminarily, first, second and third steps are carried out to the processing object image, the first step calculating similarity between the image of a retrieval region and the model image of each scanning position by scanning the retrieval region of the same size as the model image in the unit of pixel as a processing object image, the second step resetting up a retrieval region at a position extracted based on the similarity calculated in the first step, extracting an edge pixel corresponding to an edge pixel in a model image whose edge position in the sub-pixel unit is registered in the retrieval region, extracting an edge position in the unit of sub-pixel by retrieving the density gradient direction of each extracted edge pixel based on each edge pixel, and executing a processing of calculating the quantity of deviation between the edge position in the sub-pixel unit thus obtained and the registered edge position for each extracted edge pixel, the third step correcting a setting position of the retrieval region according to the quantity of deviation calculated in the second step and specifying a setting position after correction as the position of the object.