Method and device for detecting copies in a stream of visual data

A device for detecting copies or near-copies of images, comprising:

• a receiver module adapted to receive an initial image;
• a conversion module adapted to convert the initial image to grayscale;
• a resizing module adapted to resize the grayed image to a reduced image having a plurality of rows and an even number of columns;
• a computing module adapted to compute an overall signature for the reduced image;
• and
• a comparison module adapted to compare the overall signature of the reduced image to reference image signatures in order to determine whether the initial image is a copy or near-copy of an image according to the result of the comparison;
• the device wherein the computing module comprises:
• a component for computing a row signature for each row of the reduced image, the computation being based on a comparison of values obtained statistically across subsets of symmetrical pixels of each row;
• and
• a component for concatenating the row signatures in order to obtain an overall signature.

A method for generating a reference image signature, comprising the steps of:

• receiving an initial reference image;
• converting the initial reference image to grayscale;
• resizing the grayed reference image to a reduced reference image having a plurality of rows and an even number of columns;
• computing a row signature for each row of the reduced reference image, said computation being based on a comparison of values obtained statistically across subsets of symmetrical pixels in each row;
• and
• concatenating the row signatures in order to obtain a reference image signature.

A device for generating a reference image signature, comprising:

• a receiver module adapt to receive an initial reference image;
• a conversion module adapt to convert the initial reference image to grayscale;
• a resizing module adapt to resize the grayed reference image to a reduced reference image having a plurality of rows and an even number of columns;
• a computing module adapt to compute a row signature for each row of the reduced reference image, said computation being based on a comparison of values obtained statistically across subsets of symmetrical pixels in each row;
• and
• a module for concatenating the row signatures and obtaining a reference image signature.