Imaging apparatus for correcting a distortion of an image

• US 7,643,701 B2
• Filed: 08/31/2005
• Issued: 01/05/2010
• Est. Priority Date: 09/02/2004
• Status: Active Grant

• Current Assignee: Casio Computer Company Limited
• Original Assignee: Casio Computer Company Limited
• Inventors: Sakurai, Keiichi
• Primary Examiner(s): Johns; Andrew W
• Assistant Examiner(s): Thomas; Mia M
• Application Number:
  US11/216,964
• Publication Number:
  US 20060043264A1
• Time in Patent Office: 1,588 Days
• Field of Search: 382/190, 382/199, 382/276, 382/293, 382/294, 382/282
• US Class Current: 382/282
• CPC Class Codes: G06T 3/00 Geometric image transformations in the plane of the image
• CPC Class Codes: G06T 5/80 Geometric correction
• CPC Class Codes: G06V 30/1478 of characters or characters lines
• CPC Class Codes: H04N 1/00283 with a television apparatus
• CPC Class Codes: H04N 1/047 Detection, control or error compensation of scanning velocity or position H04N1/0402 and H04N1/17 take precedence
• CPC Class Codes: H04N 1/195 the array comprising a two-dimensional array or a combination of two-dimensional arrays
• CPC Class Codes: H04N 1/19594 using a television camera or a still video camera
• CPC Class Codes: H04N 1/387 Composing, repositioning or otherwise geometrically modifying originals
• CPC Class Codes: H04N 2201/0436 Scanning a picture-bearing surface lying face up on a support H04N2201/0434 takes precedence; using cylindrical picture bearing surfaces H04N1/06; with manual scanning H04N1/107
• CPC Class Codes: H04N 2201/04703 using the scanning elements as detectors, e.g. by performing a prescan
• CPC Class Codes: H04N 2201/04717 on the scanned sheet, e.g. a reference sheet
• CPC Class Codes: H04N 2201/0472 on or adjacent the sheet support
• CPC Class Codes: H04N 2201/04732 Detecting at infrequent intervals, e.g. once or twice per line for main-scan control
• CPC Class Codes: H04N 2201/04787 by changing or controlling the addresses or values of pixels, e.g. in an array, in a memory, by interpolation
• CPC Class Codes: H04N 2201/04793 using stored control or compensation data, e.g. previously measured data

Abstract

A document camera (1) detects a figure of a known shape on a stage (13) and acquires the coordinates of the figure, and acquires image processing area and projection correction parameter. The document camera (1) extracts image data of the image processing area from image data acquired by shooting the stage (13) and an original (4), and performs projection correction on the image data using the projection correction parameter. Further, the document camera (1) performs rotation correction on image data undergone projection correction. Furthermore, the document camera (1) performs zoom correction on image data undergone rotation correction, and generates output input image.

Claims

1. An imaging apparatus comprising:

an area acquisition section which acquires an area from which an image is to be extracted, based on an input image acquired by shooting, a stage and an original placed on the stage, along an oblique direction;

a storage section which prestores information indicating a figure of a known shape;

an extraction section which extracts from the input image the image corresponding to the area acquired by the area acquisition section;

a parameter acquisition section which acquires a parameter for correcting the image extracted by the extraction section to an image of the original as seen from the front; and

a correction section which corrects the image extracted by the extraction section to the image of the original as seen from the front using the parameter acquired by the parameter acquisition section, wherein the area acquisition section is configured to;

(i) acquire straight lines representing a boundary between an area of the input image occupied by the stage and an image area of the input image occupied by the original, (ii) upon acquisition of the straight lines representing the boundary, acquire an area surrounded by the straight lines or the figure of the known shape to acquire the area from which the image is to be extracted; and

(iii) when the straight lines representing the boundary are not acquired, acquire the area from which the image is to be extracted based on the prestored information indicating the figure of the known shape stored in the storage section.

2. The imaging apparatus according to claim 1, wherein the figure of the known shape represents a contour of the stage, and when the straight lines representing the boundary are not acquired, the area acquisition section acquires an area in the input image which corresponds to the stage to acquire the area from which the image is to be extracted.

3. The imaging apparatus according to claim 1, wherein the figure of the known shape is laid out on a surface of a portion of the stage where the original is to be placed, and when the straight lines representing the boundary are not acquired, the area acquisition section acquires an area in the input image which corresponds to the figure to acquire the area from which the image is to be extracted.

4. The imaging apparatus according to claim 1, wherein plural marks of known shapes are laid out on a surface of a portion of the stage where the original is to be placed, and when the straight lines representing the boundary are not acquired, the area acquisition section acquires a figure whose apexes are positions of the plural marks from the input image, and acquires an area in the input image which is occupied by the figure to acquire the area from which the image is to be extracted.

5. The imaging apparatus according to claim 1, further comprising a parameter memory section which stores the parameter acquired by the parameter acquisition section, and wherein the correction section reads the parameter stored in the parameter memory section, and corrects the image extracted by the extraction section to the image of the original as seen from the front using the read parameter.

6. The imaging apparatus according to claim 1, wherein the extraction section compresses the extracted image for each range represented by a set of pixels constituting the extracted image, and generates an image to be subjected to image processing by the correction section.

7. The imaging apparatus according to claim 1, wherein the correction section performs image processing of correcting the image extracted by the extraction section to the image of the original as seen from the front using the parameter acquired by the parameter acquisition section and compresses the image acquired by the image processing for each range represented by a set of pixels constituting the image acquired by the image processing.

8. The imaging apparatus according to claim 1, further comprising a change acquisition section which computes a change in an image based on a first image acquired by shooting the stage and the original placed on the stage at a first timing, and a second image acquired by shooting the stage and the original placed on the stage at a second timing that is different from the first timing, wherein when the change acquired by the change acquisition section is greater than a preacquired threshold, the extraction section compresses the first image for each range represented by section compresses the first image for each range represented by a set of pixels constituting the first image, and generates an image to be subjected to image processing by the correction section.

9. The imaging apparatus according to claim 1, further comprising:

a change acquisition section which computes a change in image data based on a first image acquired by shooting the stage and the original placed on the stage at a first timing, and a second image acquired by shooting the stage and the original placed on the stage at a second timing that is different from the first timing; and

a processing section which compresses an image obtained as a result of the correction section performing image processing for the first image, for each range represented by a set of pixels constituting the first image, when the change acquired by the change acquisition section is greater than a preacquired threshold.

10. The imaging apparatus according to claim 1, further comprising:

a rotation parameter acquisition section which acquires a parameter for rotating an image, obtained through image processing by the correction section, on a coordinate plane; and

a rotation correction section which rotates the image obtained through image processing by the correction section by using the parameter acquired by the rotation parameter acquisition section.

11. The imaging apparatus according to claim 10, further comprising:

a zoom parameter acquisition section which acquires a parameter for zooming in or out in an image, obtained through image conversion by the rotation correction section, on a coordinate plane; and

a zoom correction section which zooms in or out in the image obtained by rotation by the rotation correction section by using the parameter acquired by the zoom parameter acquisition section.

12. The imaging apparatus according to claim 1, further comprising:

a zoom parameter acquisition section which acquires a parameter for zooming in or out in an image, obtained through image conversion by the correction section, on a coordinate plane; and

a zoom correction section which zooms in or out in the image obtained through image processing by the correction section by using the parameter acquired by the zoom parameter acquisition section.

13. The imaging apparatus according to claim 1, further comprising:

an imaging section which acquires the input image by shooting the stage and the original placed on the stage;

a pole brace on which the imaging section is mounted; and

a tilt detection section which detects a change in tilting of the pole brace, wherein when the change detected by the tilt detection section is greater than a preacquired value, the parameter acquisition section acquires the parameter for correcting the input image to the image as seen from the front, and the correction section corrects the input image to the image of the original as seen from the front using the parameter extracted by the parameter acquisition section.