Method and a device for matching images

A method for determining the degree of correspondence between a first image and a second image, each image consisting of a plurality of binary pixels and having partially overlapping contents, comprising the following steps:

• forming a score retrieval number using one or more pixel values from the first image and one or more pixel values from the second image;
• using the score retrieval number to simultaneously retrieve at least two scores;
• each score being a fixed correlation value for a relative displacement of the pixel values from the first image with respect to the pixel values from the second image;
• and
• using the scores in determining the degree of correspondence between the contents of the first image and the second image.

A method of determining a correlation score for a first and a second image having partially overlapping contents, each image being stored in a memory in the form of a pixelmap each pixel being binary and having two conditions, one and zero, comprising the steps of:

• selecting at least two pixels from the first image, forming at least two first bits,
• selecting at east two pixels from the second image, forming at least two second bits;
• forming a binary address by defining said at least two first bits as the least significant bits of said address and said at least two second bits as the most significant bits of said address;
• and
• accessing a table by said binary address to retrieve at least one correlation score.

A device for determining a match between a first and a second image having partially overlapping contents, each image being stored in a memory in the form of a pixelmap each pixel being binary and having two conditions, one and zero, comprising:

• a selection means for selecting at least two pixels from the first image, forming at least two first bits;
• a selection means for selecting at least two pixels from the second image, forming at least two second bits;
• an address means for forming a binary address by defining said at least two first bits as the least significant bits of said address and said at least two second bits as the most significant bits of said address;
• and
• an access means for accessing a table by said binary address to retrieve at east one correlation score.