JP2936766B2 - Image input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for an image input device of an image recognition device. In particular, the present invention relates to an image input device for inputting a reading target such as a text or an address written on a sheet, such as when an address or address printed on a mail is optically read.

[0002]

2. Description of the Related Art Conventionally, an image input apparatus performs binarization according to the distribution of the number of pixels for each density.

[0003]

However, such a conventional image input device has a drawback that binarization is not correctly performed when the ground color is uneven.

An object of the present invention is to solve the above-mentioned drawbacks, and an object of the present invention is to provide an image input apparatus capable of correctly binarizing even when the background color is uneven.

[0005]

According to the present invention, there is provided an image input apparatus provided with a binarizing means for binarizing an input image, wherein the binarizing means respectively converts the input images based on mutually different threshold values. A plurality of binarizing units for binarizing, a labeling processor that performs labeling based on output signals of the plurality of binarizing units, and a plurality of binarizing units based on a labeling result of each of the labeling processors. And a selector for selecting an output signal.

According to the present invention, the input image may be an image obtained by scanning a character written on a paper sheet and converting the character into an electric signal.

Furthermore, the present invention can include means for comparing the labeling results of the respective labeling processors and selecting based on the number of patterns.

[0008]

The binarizing means binarizes the input image based on different threshold values in the plurality of binarizing units. The labeling processor performs labeling based on the output signals of the plurality of binarizing units. The selection unit selects output signals of a plurality of binarization units based on a labeling result of each labeling processor.

The input image may be an image obtained by scanning a character written on a paper sheet and converting the character into an electric signal.

Further, the selection unit can compare the labeling results of the respective labeling processors and select based on the number of patterns. As described above, binarization can be correctly performed even when the ground color is uneven.

[0011]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an image input apparatus according to an embodiment of the present invention. In FIG. 1, the image input device includes a binarizing unit for binarizing an input image 11.

Here, a feature of the present invention is that the binarizing means includes a plurality of binarizing sections 12 and 13 for binarizing the input image based on mutually different thresholds, respectively.
A labeling processor 1 that performs labeling based on the binarized images 14 and 15 output from the plurality of binarization units 12 and 13, respectively;
6, 17 and based on the labeling results 18, 19 of the respective labeling processors 16, 17, select the binarized images 14, 15 output by the binarizing units 12, 13 and select the best binarized image 22 and its corresponding. And a selection unit 20 that outputs a labeling result 21.

The input image 11 is an image obtained by scanning characters written on paper sheets and converting the characters into electric signals.

Further, the selecting section 20 includes means for comparing the labeling results 18, 19 of the respective labeling processors 16, 17 and selecting and outputting a binarized image having a small number based on the number of patterns.

The operation of the image input apparatus having such a configuration will be described. FIG. 2 is a diagram showing an image obtained by binarizing an input image of the image input device of the present invention based on a threshold value of a light eye. FIG. 3 is a diagram showing a result of labeling the binarized image shown in FIG. 2 by the image input device of the present invention. FIG. 4 is a diagram showing an image obtained by binarizing an input image of the image input apparatus of the present invention based on a dark threshold value. FIG. 5 is a diagram showing a result of labeling the binarized image shown in FIG. 4 by the image input device of the present invention.

In FIG. 1, an input image 11 is input to two sets of a binarization unit 12 and a binarization unit 13. The binarization unit 12 and the binarization unit 13 binarize the input image using different threshold values, and output a binarized image 14 and a binarized image 15. The binarized image 14 and the binarized image 15 are input to a labeling processor 16 and a labeling processor 17, respectively, and labeling is performed, and a labeling result 18 and a labeling result 19 are obtained. The selection unit 20 selects and outputs a better labeling result 21. Further, a binarized image 22 corresponding to the labeling result 21 is selected and output.

FIG. 2 shows an example of an image obtained by binarizing an input image with a light threshold value. A lot of paper noise is generated, and if labeling is performed, a labeling result including many fine unnecessary patterns as shown in FIG. 3 is obtained, which is not suitable for various processes thereafter.

FIG. 4 is an example of an image obtained by binarizing an input image with a dark threshold value. When the paper noise disappears and labeling is performed, a good labeling result as shown in FIG. 5 is obtained.

In general, the labeling result in the state shown in FIG. 3 includes a larger number of patterns than the labeling result shown in FIG. Therefore, in this embodiment, the smaller number is selected by comparing the number of patterns.

(Documents on labeling, edited by The Institute of Electronics, Information and Communication Engineers: Electronic Information and Communication Handbook, 5.2-valued images, PP.1106
1108, Onoe: Image Processing Handbook, 13.3 Topology of Figures and Topology Preservation Conversion, PP.317-318)

[0021]

As described above, the present invention has an excellent effect that binarization can be correctly performed even when the ground color is uneven.

[Brief description of the drawings]

FIG. 1 is a block diagram of an image input device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an image obtained by binarizing an input image of the image input apparatus according to the present invention based on a threshold value of light eyes.

FIG. 3 is a diagram showing a result of labeling the binarized image shown in FIG. 2 by the image input device of the present invention.

FIG. 4 is a diagram showing an image obtained by binarizing an input image of the image input apparatus according to the present invention based on a dark threshold value.

FIG. 5 is a diagram showing a result of labeling the binarized image shown in FIG. 4 by the image input device of the present invention.

[Explanation of symbols]

 11 Input image 12, 13 Binarization section 14, 15, 22 Binarization image 16, 17 Labeling processor 18, 19 Labeling result 20 Selection section 21 Labeling result

Continuation of the front page (56) References JP-A-63-283272 (JP, A) JP-A-2-228878 (JP, A) JP-A-2-24787 (JP, A) JP-A-59-60579 (JP) JP-A-4-282777 (JP, A) JP-A-4-282791 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06T 1/00 H04N 1/403

Claims (3)

(57) [Claims] A plurality of binarization units for respectively binarizing an input image based on mutually different threshold values; and an input image based on output signals of the plurality of binarization units.
An image input device, comprising: a plurality of labeling processors for performing image labeling; and a selection unit that selects output signals of the plurality of binarization units based on a labeling result of each of the labeling processors. 2. The image input device according to claim 1, wherein the input image is an image obtained by scanning a character written on a paper sheet and converting the character into an electric signal. 3. The image input apparatus according to claim 1, wherein said selection unit includes means for comparing labeling results of said labeling processors and selecting based on the number of patterns.