IMAGE MATCHING APPARATUS, IMAGE MATCHING METHOD, AND IMAGE DATA OUTPUT PROCESSING APPARATUS

• US 20090067724A1
• Filed: 09/04/2008
• Published: 03/12/2009
• Est. Priority Date: 09/07/2007
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: HIROHATA, Hitoshi
• Granted Patent: US 8,050,501 B2
• Time in Patent Office: Days
• US Class Current: 382/190
• CPC Class Codes: G03G 21/046 by discriminating a special original, e.g. a bank note
• CPC Class Codes: G06V 30/10 Character recognition
• CPC Class Codes: G06V 30/166 Normalisation of pattern dimensions
• CPC Class Codes: G06V 30/40 Document-oriented image-based pattern recognition

Abstract

In an image matching apparatus of the present invention, when a document type discrimination section that discriminates a document type determines that a target document is an N-up document on which plural document images are laid out, a resolution conversion section that converts a resolution of image data into a default resolution before features are extracted from the image data converts a resolution of image data of the target document into not the default resolution but a resolution which varies depending on the number of document images laid out on the target document and a document size of the target document. This makes it possible to determine a similarity to a reference document with high accuracy even in a case where each document image included in the target document to be matched is reduced in size from its original document image, i.e., in a case of an N-up document.

Claims

1. An image matching apparatus, comprising:

a features extraction section for extracting features of an image from input image data,

said apparatus (i) causing the features extraction section to extract the features from input image data of a target document to be matched, and (ii) determining whether or not the target document has a similar image to that of a preliminarily stored reference document based on a comparison of the features thus extracted with features of the image of the reference document;

said apparatus, further comprising;

a resolution conversion section that converts a resolution of the input image data into a default resolution so that the resolution of the input image data is decreased, before the features are extracted from the input image data;

an N-up document determination section that determines (i) whether or not the target document is an N-up document on which plural documents are laid out, and (ii) the number of images laid out on the N-up document when it is determined that the target document is an N-up document; and

a document size detection section that detects a document size of the target document,

when the N-up document determination section determines that the target document is an N-up document, the resolution conversion section converting a resolution of the image data of the target document into not the default resolution but a resolution which varies depending on the number of the images laid out on the N-up document and the document size that are found and detected by the N-up document determination section and the document size detection section, respectively.

2. The image matching apparatus as set forth in claims 1, wherein:

the resolution conversion section includes a resolution conversion table in which resolutions are set so as to vary depending on combinations of the number of the images laid out on the N-up document and a document size, and refers to the table so as to convert a resolution of the target document into a resolution which varies depending on the number of the images laid out on the N-up document and the document size.

3. The image matching apparatus as set forth in claim 1, wherein:

the features extraction section extracts a connected region in which pixels are connected to each other, and finds the features based on the connected region thus extracted.

6. A computer-readable storage medium in which a program, causing an image matching apparatus as set forth in claim 1 to operate, is stored, said program causing a computer to function as respective sections in the image matching apparatus.

4. An image data output processing apparatus that carries out an output process with respect to image data, the image data output processing apparatus, comprising:

an image matching apparatus; and

an output process control section that controls the output process with respect to image data of a target document to be matched in accordance with a determination result of the image matching apparatus,

said image matching apparatus, including;

a features extraction section for extracting features of an image from input image data,

said image matching apparatus (i) causing the features extraction section to extract the features from input image data of a target document to be matched, and (ii) determining whether or not the target document has a similar image to that of a preliminarily stored reference document based on a comparison of the features thus extracted with features of the image of the reference document;

said image matching apparatus, further including;

a resolution conversion section that converts a resolution of the input image data into a default resolution so that the resolution of the input image data is decreased, before the features are extracted from the input image data;

an N-up document determination section that determines (i) whether or not the target document is an N-up document on which plural documents are laid out, and (ii) the number of images laid out on the N-up document when it is determined that the target document is an N-up document; and

a document size detection section that detects a document size of the target document,

when the N-up document determination section determines that the target document is an N-up document, the resolution conversion section converting a resolution of the image data of the target document into not the default resolution but a resolution which varies depending on the number of the images laid out on the N-up document and the document size that are found and detected by the N-up document determination section and the document size detection section, respectively.

5. An image matching method comprising the step of:

(a) extracting features of an image from input image data,

wherein the features are extracted from input image data of a target document to be matched in the step (a), and it is determined whether or not the target document has a similar image to that of a preliminarily stored reference document, based on a comparison of the features thus extracted with features of the image of the reference document;

said method, further comprising the steps of;

(b) converting a resolution of the input image data into a default resolution so that the resolution of the input image data is decreased, before the features are extracted from the input image data;

(c) determining (i) whether or not the target document is an N-up document on which plural documents are laid out, and (ii) the number of the images laid out on the N-up document when it is determined that the target document is an N-up document; and

(d) detecting a document size of the target document,

when it is determined that the target document is an N-up document in the step (c), the step (b) being carried out such that a resolution of the image data of the target document is converted into not the default resolution but a resolution which varies depending on the number of the images laid out on the N-up document and the document size that are found and detected in the steps (c) and (d), respectively.