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Image processing apparatus and determination method

a technology of image processing and determination method, which is applied in the field of image processing apparatus, can solve the problems of difficult to difficult to accurately detect the document region, and the size may be erroneously detected, and achieve the effect of high accuracy

Inactive Publication Date: 2014-09-09
CANON KK
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011]An aspect of the present invention is to eliminate the above-mentioned problems with the conventional technology. The present invention provides an image processing apparatus which detects a document region with high accuracy and a determination method.
[0014]According to the present invention, it is possible to detect a document region with high accuracy.

Problems solved by technology

If, however, a background has a color close to that of a document region, it is very difficult to detect the document region.
That is, it is difficult to accurately detect a document region by using the technique disclosed in Japanese Patent Laid-Open No. 2001-256491 in consideration of (a) plain paper improved in the degree of whiteness with high use frequency, (b) reading of a text document mostly occupied by non-printed regions, and (c) a white sheet used on a surface of a document table cover which comes into contact with a document table.
In addition, according to the detection method using the sensors disclosed in Japanese Patent Laid-Open No. 61-20936, when the user places a plurality of documents with small sizes such as name cards, the sizes may be erroneously detected.
Furthermore, the cost of the apparatus increases by the number of sensors mounted in the apparatus.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

first embodiment

Arrangement of Image Reading Apparatus

[0038]FIG. 1 is a perspective view showing an outline of an image reading apparatus according to an embodiment of the present invention. An image reading apparatus 100 includes a document table cover 101 which holds a set document so as to cover it, a document table (platen) 102 on which a document is to be placed, and a document reading unit 103 for reading a set document. When the user places a document on the document table 102, the image reading apparatus 100 drives the document reading unit 103 by using a motor (not shown) to optically read the document by using a light source installed in the document reading unit 103 and sensors (not shown) which detect reflection signals.

[0039]FIG. 2 is a block diagram showing the internal arrangement of the image reading apparatus 100 and the internal arrangement of the host apparatus (for example, a PC) 300. Referring to FIG. 2, a CPU 201 controls the overall image reading apparatus 100 and executes pr...

second embodiment

[0071]The first embodiment improves the accuracy of determination on whether each region is a document region by performing a plurality of pixel determination processes like those in steps S702 to S705 in FIG. 7. In contrast to this, the second embodiment allows to change the scalability of each pixel determination process in the first embodiment. Only points different from the first embodiment will be described below.

[0072]This embodiment gives consideration to a case in which the user selects a document type via a user interface window or a case in which an ADF (Auto Document Feeder) which automatically reads documents is used. That is, the embodiment gives consideration to a case in which it is obvious that plain paper documents will be used.

[0073]FIG. 18 is a flowchart showing a procedure for pixel determination processing in this embodiment. This processing corresponds to pixel determination processing in step S602 in FIG. 6. Step S1801 in FIG. 18 corresponds to step S701 in FI...

third embodiment

[0078]The first and second embodiments use binary determination on whether a target pixel is a document portion. The third embodiment can further improve the accuracy by performing multilevel determination processing. Only points different from the first embodiment will be described below.

[0079]FIG. 20 is a flowchart showing a procedure for pixel determination processing in this embodiment. This processing corresponds to the pixel determination processing in step S602 in FIG. 6. Step S2001 in FIG. 20 corresponds to step S701 in FIG. 7. Step S2007 in FIG. 20 corresponds to step S709 in FIG. 7. Steps S2002 to S2005 correspond to steps S702 to S705 in FIG. 7 in terms of the evaluation values (signal values representing optical characteristics) used for processing, but differ from them in the first embodiment in terms of binarization processing executed at the last stage in each process.

[0080]FIGS. 21A to 21D are graphs for determining document degrees in steps S2002, S2003, S2004, and ...

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PUM

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Abstract

A signal value representing at least one of a plurality of types of optical characteristics are calculated for each pixel from the read signal obtained and output by reading light reflected by a document placed on a document table and a document table cover while the document is covered with the cover. It is determined, based on the signal value calculated, whether or not a target pixel is a pixel in a document region. A document region is detected from the determination result.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an image processing apparatus which detects a document region and a determination method.[0003]2. Description of the Related Art[0004]Image reading apparatuses designed to optically read documents and photographs and convert the read data into electronic data are widely known. Recently, in general, such apparatuses have been used as multifunctional apparatuses having multiple functions such as a printing function, data transmission / reception function, copying function, and facsimile function as well as being used in a single standalone form. The hardware resource environment including CPUs, memories, and liquid crystal screens, which execute these processes, has remarkably advanced and greatly improved in performance. It is regarded important to provide more comfortable use environments to users by making the most use of these hardware resources. For example, it is important to provide a...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): H04N1/04G06K15/00G06K9/46G06K9/50G06K9/48H04N1/387G06K9/20H04N1/00H04N1/38H04N1/46
CPCG06K9/20H04N1/387G06K9/4638H04N1/00681H04N1/00816H04N1/38H04N1/46
Inventor SUWA, TETSUYAKATO, MINAKOMOCHIZUKI, YUGONAKAMURA, TAKASHIKATO, MASAO
Owner CANON KK