Picture retrieving apparatus and method which converts orthogonal transform coefficients into color histogram data

• US 20070223837A1
• Filed: 05/23/2007
• Published: 09/27/2007
• Est. Priority Date: 09/06/2000
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yamada, Akio, Kasutani, Eiji
• Granted Patent: US 7,457,460 B2
• Time in Patent Office: Days
• US Class Current: 382/276
• CPC Class Codes: G06F 16/5838 using colour
• CPC Class Codes: G06T 7/97 Determining parameters from multiple pictures depth or shape recovery from multiple images G06T7/55; stereo camera calibration G06T7/85
• CPC Class Codes: G06V 10/507 Summing image-intensity values; Histogram projection analysis
• CPC Class Codes: G06V 10/56 relating to colour

Abstract

The picture retrieving apparatus includes: an orthogonal conversion coefficient memory 13 of a retrieval target picture storing an orthogonal conversion coefficient of a picture targeted for a retrieval; a picture feature amount converter 2 converting an orthogonal conversion coefficient 21 read from the orthogonal conversion coefficient memory 13 of the retrieval target picture into a color histogram information; and a color histogram similarity calculator 4 calculating a similarity 42 between a color histogram information 41 of a query picture and a color histogram information 25 generated by the picture feature amount converter 2. It unifies the kinds of the picture feature amounts to calculate the similarity between the picture feature amounts. Thus, it can specify the picture similar to the query picture from the retrieval target picture, on the basis of the calculated similarity.

Claims

1. A picture retrieving apparatus, comprising:

a first orthogonal coefficient generating section which outputs a set of orthogonal coefficients of each of a plurality of pictures as a retrieval target picture;

a second orthogonal coefficient generating section which outputs a set of orthogonal coefficients of a query picture; and

an orthogonal transform coefficient similarity calculator which calculates a similarity between said set of orthogonal transform coefficients of said query picture and said set of orthogonal transform coefficient of said retrieval target picture.

2. The picture retrieving apparatus according to claim 1, wherein said first orthogonal transform coefficient generating section comprises:

a color histogram memory which stores a plurality of color histogram data of said plurality of pictures;

a first picture feature data converter which converts said color histogram data of said retrieval target picture read from said color histogram memory into said set of orthogonal transform coefficients of said retrieval target picture, and outputs to said orthogonal transform coefficient similarity calculator.

3. The picture retrieving apparatus according to claim 2, wherein said first picture feature data converter comprises:

an average color calculator which calculates an average color from said color histogram data of said retrieval target picture; and

an orthogonal transform coefficient generating section which generates said set of orthogonal transform coefficient of said retrieval target picture using said calculated average color as a direct current component.

4. The picture retrieving apparatus according to claim 1, said second orthogonal coefficient generating section comprises:

a second picture feature data converter which converts a color histogram data of said query picture into said set of orthogonal transform coefficients.

5. The picture retrieving apparatus according to claim 4, wherein said second picture feature data converter comprises:

an average color calculator which calculates an average color from said color histogram data of said query picture; and

an orthogonal transform coefficient generating section which generates said set of orthogonal transform coefficients of said query picture using said calculated average color as a direct current component.

6. A picture retrieving method, comprising:

(a) outputting a set of orthogonal coefficients of each of a plurality of pictures as a retrieval target picture;

(b) outputting a set of orthogonal coefficients of a query picture; and

(c) calculating a similarity between said set of orthogonal transform coefficients of said query picture and said set of orthogonal transform coefficient of said retrieval target picture.

7. The picture retrieving method according to claim 6, wherein said step of (a) outputting comprises the steps of:

providing a plurality of color histogram data of said plurality of pictures;

(d) converting said color histogram data of said retrieval target picture into said set of orthogonal transform coefficients of said retrieval target picture; and

outputting said set of orthogonal transform coefficients of said retrieval target picture.

8. The picture retrieving method according to claim 7, wherein said step of (d) converting comprises the steps of:

calculating an average color from said color histogram data of said retrieval target picture; and

generating said set of orthogonal transform coefficient of said retrieval target picture using said calculated average color as a direct current component.

9. The picture retrieving method according to claim 6, said step of (b) outputting comprises the step of:

(e) converting a color histogram data of said query picture into said set of orthogonal transform coefficients.

10. The picture retrieving method according to claim 9, wherein said step of (e) converting comprises the steps of:

calculating an average color from said color histogram data of said query picture; and

generating said set of orthogonal transform coefficients of said query picture using said calculated average color as a direct current component.