Method and system for finding a document image in a document collection using localized two-dimensional visual fingerprints

An image management method for storing, indexing, searching, and/or retrieving image data comprising the steps of:

• identifying keypoints in images, including keypoints in a query image of a query document and keypoints in potential target document images of a collection of potential target documents;
• generating fingerprint information from the keypoints;
• comparing the fingerprint information of the query image with fingerprint information of the potential target document images in the collection of potential target documents;
• determining a best match between the fingerprint information of the query image and the potential target document images;
• retrieving at least one target document image based on the determining step;
• and
• at least one of displaying, printing, storing or transmitting the retrieved at least one target document image;
• and,
• applying a weighted fingerprint scoring analysis, which includes processing counts of matching fingerprints in selected image zones of the query image and the target images.

An image management method for storing, indexing, searching, and/or retrieving image data comprising the steps of:

• identifying keypoints in images, including keypoints in a query image of a query document and keypoints in potential target document images of a collection of potential target documents;
• generating fingerprint information from the keypoints;
• comparing the fingerprint information of the query image with fingerprint information of the potential target document images in the collection of potential target documents;
• determining a best match between the fingerprint information of the query image and the potential target document images;
• retrieving at least one target document image based on the determining step;
• at least one of displaying, printing, storing or transmitting the retrieved at least one target document image;
• and,
• applying a noise guard process in a candidate fingerprint selection process when one or more of determined triangle ratios in a fingerprint sequence of a query image falls within a predetermined tolerance level of quantization thresholds, wherein if a distance from a persistent ratio value to its nearest quantization threshold is below a pre-specified tolerance level, the noise guard generates each relevant quantization sequence of candidate fingerprints.

An image management system within a computer operable system for storing, indexing, searching, and/or retrieving image data comprising:

• an identification module configured to identify keypoints in images, including keypoints in a query image of a query document and keypoints in potential target document images of a collection of potential target documents;
• a fingerprint generation module configured to generate fingerprint information from the keypoints, wherein fingerprints of the fingerprint information are sequences of quantized transformation-invariant two-dimensional persistent ratios;
• a comparison module configured to compare the fingerprint information of the query image with fingerprint information of the potential target document images in the collection of potential target documents;
• a matching module configured to determine a best match between the fingerprint information of the query image and the potential target document images;
• a retrieval module configured to retrieve at least one target document image based on the determining step;
• and
• at least one of an electronic display, a printer, a memory storage or a computer network to display, print, store or transmit the retrieved at least one target document image;
• wherein a noise guard method is employed to compensate for errors.