System and method for rotation invariant representation of texture in images

For use in an image retrieval system, an image processing device capable of receiving an image having associated therewith a first texture representation specified in a rotation variant format associated with a central reference point and converting said first texture representation to a second texture representation specified in a rotation invariant format, said image processing device comprising:

• an image processor capable of analyzing rotation variant texture parameters associated with said first texture representation and determining therefrom a plurality of rotation invariant texture parameters disposed along at least one radial line extending through said central reference point, wherein said plurality of rotation invariant texture parameters comprise said second texture representation;
• wherein said image processor is capable of determining from said plurality of rotation invariant texture parameters an angular amount of rotation between said image and a rotated version of said image;
• wherein said image processor determines said angular amount of rotation between said image and said rotated version of said image by rotating said plurality of rotation invariant texture parameters to a plurality of rotation points in increments of 180/K degrees, where K is a number of said at least one radial line, comparing said plurality of rotation invariant texture parameters with a second plurality of rotation invariant texture parameters associated with said rotated version of said image at each of said plurality of rotation points, and determining a selected one of said plurality of rotation points at which a minimum difference occurs between said plurality and said second plurality of rotation invariant texture parameters.

An image retrieval system, comprising:

• an image processing device capable of receiving an image having associated therewith a first texture representation specified in a rotation variant format associated with a central reference point and converting said first texture representation to a second texture representation specified in a rotation invariant format, said image processing device comprising:
• an image processor capable of analyzing rotation variant texture parameters associated with said first texture representation and determining therefrom a plurality of rotation invariant texture parameters disposed along at least one radial line extending through said central reference point, wherein said plurality of rotation invariant texture parameters comprise said second texture representation;
• a display monitor for displaying said image;
• and
• a user input device for receiving user commands capable of selecting said image and causing said image processor to determine said one of said first and second pluralities of rotation invariant texture parameters;
• wherein a number of said plurality of rotation invariant texture parameters is equal to a number of said at least one radial line.

An image retrieval system, comprising:

• an image processing device capable of receiving an image having associated therewith a first texture representation specified in a rotation variant format associated with a central reference point and converting said first texture representation to a second texture representation specified in a rotation invariant format, said image processing device comprising:
• an image processor capable of analyzing rotation variant texture parameters associated with said first texture representation and determining therefrom a plurality of rotation invariant texture parameters disposed along at least one radial line extending through said central reference point, wherein said plurality of rotation invariant texture parameters comprise said second texture representation;
• a display monitor for displaying said image;
• and
• a user input device for receiving user commands capable of selecting said image and causing said image processor to determine said one of said first and second pluralities of rotation invariant texture parameters;
• wherein said image processor is capable of determining from said plurality of rotation invariant texture parameters an angular amount of rotation between said image and a rotated version of said image;
• wherein said image processor determines said angular amount of rotation between said image and said rotated version of said image by rotating said plurality of rotation invariant texture parameters to a plurality of rotation points in increments of 180/K degrees, where K is a number of said at least one radial line, comparing said plurality of rotation invariant texture parameters with a second plurality of rotation invariant texture parameters associated with said rotated version of said image at each of said plurality of rotation points, and determining a selected one of said plurality of rotation points at which a minimum difference occurs between said plurality and said second plurality of rotation invariant texture parameters.

For use in an image retrieval system, a method of converting a texture representation of an image from a rotation variant texture representation associated with a central reference point to a rotation invariant texture representation, the method comprising the steps of:

• analyzing rotation variant texture parameters associated with the rotation variant texture representation and determining therefrom a plurality of rotation invariant texture parameters disposed along at least one radial line extending through the central reference point, wherein the plurality of rotation invariant texture parameters comprise the rotation invariant texture representation;
• determining from the plurality of rotation invariant texture parameters an angular amount of rotation between the image and a rotated version of the image;
• wherein the step of determining an angular amount of rotation comprises the steps of rotating the plurality of rotation invariant texture parameters to a plurality of rotation points in increments of 180/K degrees, where K is a number of the at least one radial line, comparing the plurality of rotation invariant texture parameters with a second plurality of rotation invariant texture parameters associated with the rotated version of the image at each of the plurality of rotation points, and determining a selected one of the plurality of rotation points at which a minimum difference occurs between the plurality and the second plurality of rotation invariant texture parameter.

For use in an image retrieval system, computer executable process steps stored on a computer readable storage medium for converting a texture representation of an image from a rotation variant texture representation associated with a central reference point to a rotation invariant texture representation, the computer executable process steps comprising:

• analyzing rotation variant texture parameters associated with the rotation variant texture representation and determining therefrom a plurality of rotation invariant texture parameters disposed along at least one radial line extending through the central reference point, wherein the plurality of rotation invariant texture parameters comprise the rotation invariant texture representation;
• determining from the plurality of rotation invariant texture parameters an angular amount of rotation between the image and a rotated version of the image;
• wherein the step of determining an angular amount of rotation comprises the steps of rotating the plurality of rotation invariant texture parameters to a plurality of rotation points in increments of 180/K degrees, where K is a number of the at least one radial line, comparing the plurality of rotation invariant texture parameters with a second plurality of rotation invariant texture parameters associated with the rotated version of the image at each of the plurality of rotation points, and determining a selected one of the plurality of rotation points at which a minimum difference occurs between the plurality and the second plurality of rotation invariant texture parameters.