JP2000201293A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera capable of outputting image data with the same size as an original which is an image pickup object. SOLUTION: The size Z of photographed image data is found based on the viewing angle θ of a camera and the distance L between an original and the camera. The distance per pixel on the original is calculated by dividing the size Z of the photographed image data by the number of the pixels of a CCD. Meanwhile, the actual size of a character on the original is calculated by detecting the number of pixels constituting the character on the original and multiplying the calculated distance by the number of pixels. The image data is printed on the basis of the calculated size so that the actual size of the character on the original is the same as the size of an outputted character.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus capable of determining the resolution of an image obtained by imaging an object to be imaged (for example, a document).

[0002]

2. Description of the Related Art Conventionally, an image pickup device such as a digital camera has been used to image a document including characters.

[0003]

However, when a document is imaged by a digital camera, the size of the document (and the characters therein) obtained as image data changes depending on the imaging distance and zoom magnification. Moreover, since the size of the original document cannot be known, the size of the original document and the printed document may change, or the size of the characters included in the original document and the printed characters may change. is there.

More specifically, by photographing an original as shown in FIG.
Assume that the image data of (B) is obtained. At this time, it is not possible to distinguish whether an image of a distant large document or an image of a nearby small document has been taken only from the image data of FIG. As a result, the output resolution of the image data cannot be set appropriately. As a result, FIG.
As shown in FIG. 6C, the document is output in a document size and character size different from the original document. Also, when printing the result of an OCR (optical character reader) of an input image, the same character size as that of the original document cannot be determined.

[0005] A method of determining whether a character can be read or not by comparing the minimum character size in the image data with the minimum readable character size determined by the resolution of the image processing apparatus. Is disclosed in JP-A-10-75349. However, such a method is a character size recognition method for an image input by an image scanner that can restrict reading conditions, and is used for character size recognition in a device such as a digital camera with less restrictions on reading conditions. Not applicable. That is, in a digital camera, the resolution of an input document image is unknown because the imaging distance and the imaging angle with respect to the imaging target are not constant. Therefore, Japanese Patent Application Laid-Open
The technique disclosed in Japanese Patent No. 75349 cannot be used as it is in a digital camera to restore the character size.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide an image processing apparatus capable of determining the resolution of an acquired image.

Another object of the present invention is to provide an image processing apparatus capable of identifying the size of a character drawn on an object to be imaged.

Another object of the present invention is to provide an image processing apparatus capable of obtaining the size of an object to be imaged.

[0009]

According to one aspect of the present invention, in order to achieve the above object, an image processing apparatus includes: an obtaining unit configured to obtain an image by capturing an image of an object; The image processing apparatus includes a measuring unit for measuring, and a resolution determining unit for determining a resolution of an image obtained using the measured distance.

Preferably, the image processing apparatus includes a storage unit for storing a plurality of sizes of the object in advance, a size determination unit for determining the size of the imaging target based on the acquired image and the measured distance, and And a correction unit configured to correct the determined resolution based on the size of the object and the determined size of the imaging target.

[0011] More preferably, the image processing apparatus further includes identification means for identifying a size of a character drawn on the object to be imaged based on the determined resolution.

According to another aspect of the present invention, an image processing apparatus includes: a storage unit for storing a plurality of sizes of an object in advance; an obtaining unit for obtaining an image by capturing an image of a target; and a distance to the target. Measurement means for measuring the size of the imaging target based on the acquired image and the measured distance, and based on the size of the stored object, Correction means for correcting the size.

Preferably, the object to be imaged is a document, and the storage means stores a plurality of fixed sizes of the document.

According to the present invention, the resolution of an obtained image can be determined. Furthermore, it is also possible to identify the size of the character drawn on the imaging target based on the determined resolution.

Further, if a plurality of object sizes are stored in advance and the size of the imaging target determined based on the stored size of the object is corrected, the size of the imaging target having a small error is obtained. be able to.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS <First Embodiment> FIG. 1 is a perspective view of a digital camera according to a first embodiment of the present invention as viewed from the front, and FIG. Camera back). Referring to the figure, the digital camera has a shooting button 3, a shooting lens unit 4, a card insertion hole 5 for inserting a card memory, a power button 6,
A correction mode setting switch 7 is provided for setting a mode in which printing is performed in the same size as a document when a character document such as a book is imaged.

The result of photographing by the digital camera is stored as electrical data in a hard disk card (card memory) inside the digital camera. Here, the card memory is a medium for image data, for example, a hard disk card conforming to PCMCIA can be used.

Further, a mini disk (MD) may be used instead of the card memory. Further, instead of using the card memory as a recording medium for image data, the image data may be directly transmitted to a printer or the like via, for example, a SCSI cable.

FIG. 3 is a block diagram showing the configuration of the digital camera according to the present embodiment. Referring to the figure, a digital camera includes a CPU 101 for controlling the entire apparatus,
A CCD unit 111 that converts light incident through the photographing lens unit 4 into an electric signal; a RAM 103 that temporarily stores a signal from the CCD unit 111; and a signal stored in the RAM 103 (ie, acquired image data ), A skew correction unit 107 for skew correction, a character size recognition unit 109 for judging the resolution of image data, and recognizing the size of characters drawn on the object to be imaged. A character size conversion unit 113 for converting the size of characters in image data based on the recognized character size, a card memory unit 117 for storing data from the character size conversion unit 113, and a distance to an object to be imaged. And a distance measuring unit 119 for measuring the distance.

The distance measuring section 119 measures the distance by a conventionally known technique such as a triangular distance measuring method. The tilt correction unit 107 and the character size recognition unit 109 perform processing based on data from the distance measurement unit 119. The data in the card memory unit 117 is sent to the printer 121 for printing.

FIG. 4 is a flowchart showing an image processing operation performed by the digital camera when the correction mode setting switch 7 is turned on. Referring to the figure, step S1
, Image data is input via the CCD unit 111 and distance measurement data is input via the distance measurement unit 119.

In step S3, distortion correction is performed by the distortion correction unit 105, and in step S5, the tilt correction unit 107
A correction is made by this. In step S7, the size of the character in the input image data is recognized.
At step S9, the image data is printed according to the character size recognized.

Hereinafter, the processing performed in each step will be described in detail. [Step S1] FIG. 5 is a diagram showing a digital camera 1 and a book 2 which is a character document photographed by the digital camera 1. When the photographing button 3 of the digital camera is pressed, image data and distance measurement data are obtained.

[Step S3] Lens distortion is corrected from the image data. Since the lens distortion is specific to the camera, it can be easily corrected.

[Step S5] Fanning correction of image data is performed. In this processing, first, an object to be imaged in the image data is identified. Next, the distance to the imaging target is measured at a plurality of locations. Then, correction is performed based on the measured distance.

Specifically, as shown in FIG. 6, the distance to the object to be imaged in the acquired image data “A” is 3
Measurement is performed at three points P1 to P3, and the image data “A” is deformed based on the distance data to obtain image data “B” without flutter.

[Step S7] As a character size recognition process, the process shown in the flowchart of FIG. 7 is performed. Referring to FIG. 7, distance measurement information is input from distance measurement unit 119 in step S101. In step S103, camera-specific information is input. The ranging information is a distance from the digital camera to the imaging target. In addition, the camera specific information is the angle of view here.

Referring to FIG. 8, the size Z of the acquired image data can be obtained from the distance L from the digital camera to the object to be imaged and the angle of view θ.

In step S105, the actual size of the image data captured by one pixel of the CCD is obtained based on the size Z of the obtained image data.

Referring to FIG. 9, the pixels of the CCD are N
× N pixels, and if image data of Z × Z size is acquired by the CCD, the actual size of the image data captured by one pixel of the CCD is
N, horizontal Z / N. Note that the actual size of the image data captured by one pixel of the CCD means the resolution of the image data.

Returning to FIG. 7, in step S107, characters in the image data are detected, and the number of pixels (vertical × horizontal) forming one character is calculated for all the characters in the image data.

For example, if the acquired image data is as shown in FIG. 10, an area in which characters are written is detected. The number of vertical and horizontal pixels of the character existing in the area is calculated.

For example, when calculating the number of pixels constituting the character of "ta" in the portion drawn as "title" in the image data of FIG. 10, the number of pixels W in the horizontal direction is calculated as shown in FIG. The number H of pixels in the vertical direction is calculated. This number of pixels can be known by a method using histogram information in the horizontal and vertical directions.

Returning to FIG. 7, in step S109, the actual number of pixels in the image data is calculated by multiplying the calculated number of pixels by the actual size (resolution) of the image data captured by one pixel. Is calculated.

[Step S9] Image data is printed so that the characters to be printed have the same size as the actual characters of the object to be imaged. Specifically, (1) changing the size of the character by changing the resolution of the character portion in the image data, or (2) OCR (optical character reader) for the image data
And character printing is performed using the character size determined in step S109 (see FIG. 7).

As described above, in the present embodiment,
It is possible to provide a digital camera capable of printing characters in the same size as the actual document character size.

<Modification> In the first embodiment,
Recognizing the actual size of the character and printing the character in the same size, as shown in FIG. 12, by examining the number of pixels (W × H) constituting the original,
The original may be printed in the same size as the actual original.

The document area can be extracted by recognizing the largest rectangle in the image data, or can be obtained by using document recognition using a method of recognizing the edge of the background area in the image data. .

<Second Embodiment> The hardware configuration of a digital camera according to the second embodiment is the same as that of the first embodiment, and thus description thereof will not be repeated. In the digital camera according to the second embodiment, the accuracy required for the ranging information can be reduced.

For example, 11-point characters and 12-point characters are often used as character sizes. However, in order to determine these two sizes, in the first embodiment, 11/12 = about 91% or more is required as the distance measurement accuracy. Therefore, when the distance measurement accuracy is low, it is difficult for the digital camera according to the first embodiment to recognize the character size.

In the second embodiment, by using a fixed original size in addition to the distance measurement information, the character size can be determined without requiring high accuracy in the distance measurement information.

It should be noted that the fixed size of the original is specifically the column A (the column A main version, which is a generally used paper size as shown in FIGS. 13A and 13B). 1
, Second edition,...) And row B (B row main version, first edition, second edition,...). Further, as the standard size, only a commonly used size such as a postcard size or a newspaper size may be used, or another size may be used.

Since a general original substantially follows these standard sizes, an error in the distance measurement accuracy can be compensated for by making the size of the original in the obtained image data coincide with the standard size. Thereby, a more accurate character size and a more accurate image resolution can be known. In addition,
The standard size is stored in the CPU 101.

In the digital camera according to the second embodiment, the processing shown in FIG. 14 is executed instead of the character size recognition processing shown in FIG. Referring to the figure, the processing in steps S201 to S205 is the same as the processing in steps S101 to S105 in FIG. 7, and thus description thereof will not be repeated.

In step S207, the size of the document area in the obtained image data is obtained by the same method as that shown in FIG. Then, step S2
In step 09, the size of the fixed form paper closest to the obtained size of the manuscript area is determined based on the vertical and horizontal sizes, and the size of the manuscript is the size of the fixed form paper.

In step S211, the determined size of the standard paper is divided by the number of pixels in the horizontal direction and the number of pixels in the vertical direction of the original image shown in FIG. The actual size (resolution) of the data is determined. In step S213, the number of pixels constituting the character in the image data is measured. Step S215
Then, the actual size of the character is calculated based on the corrected resolution and the number of pixels constituting the character.

In this embodiment, a plurality of standard paper sizes are stored in the CPU 101, and the closest standard paper size is selected from the size of the captured original image. Is identified. Thus, it is possible to know an accurate resolution without obtaining accurate ranging information.

In the present embodiment, the original image is determined to be close to which standard paper based on the vertical size and the horizontal size of the original image in the image data. The fixed size paper may be identified in consideration of the ratio between the size in the vertical direction and the size in the horizontal direction.

<Third Embodiment> In the digital camera according to the third embodiment, the processing shown in FIG. 15 is executed instead of the processing shown in FIG. FIG.
The processing in steps S301 to S311 shown in FIG.
Since the processing is the same as the processing in steps S201 to S211 in FIG. 14, the description will not be repeated here. In the digital camera according to the third embodiment, the size of a document image is determined based on a plurality of standard paper sizes, the resolution is determined based on the standard paper size, and stored. Then, based on the stored resolution, resolution conversion is performed so that the output image has the same size as the imaging target, and the image is printed.

Also in the digital camera according to the present embodiment, an image can be output in the same size as the object to be imaged (for example, an original).

In the above-described embodiment, the character size and the like are converted. However, the number of pixels of a portion constituting the photograph in the original image is obtained, and the size of the photograph is reduced based on the number of pixels. Processing such as making the same as the original image can also be performed.

Further, in the second and third embodiments, the standard paper size is stored. However, the size of another object may be stored and the size of the imaged object may be corrected. .

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a perspective view of a digital camera according to a first embodiment of the present invention as viewed from the front.

FIG. 2 is a perspective view of the digital camera as viewed from behind.

FIG. 3 is a block diagram illustrating a configuration of a digital camera.

FIG. 4 is a flowchart illustrating image processing performed by the digital camera.

FIG. 5 is a diagram for explaining an input state of image data.

FIG. 6 is a diagram for explaining a tilt correction method.

FIG. 7 is a flowchart showing the contents of a character size recognition process (S7) of FIG. 4;

FIG. 8 is a diagram for explaining a process of obtaining the size of image data to be captured from distance measurement information and camera-specific information.

FIG. 9 is a diagram for explaining a process of obtaining the size of image data corresponding to one pixel.

FIG. 10 is a diagram illustrating a specific example of input image data.

FIG. 11 is an enlarged view of a part of the image data of FIG. 10;

FIG. 12 is a diagram illustrating a process of obtaining the size of a document image.

FIG. 13 is a diagram illustrating standard paper sizes stored in a digital camera according to the second embodiment.

FIG. 14 is a flowchart illustrating a process performed by the digital camera according to the second embodiment.

FIG. 15 is a flowchart illustrating image processing performed by the digital camera according to the third embodiment.

FIG. 16 is a diagram for explaining a problem of the related art.

[Explanation of symbols]

 101 CPU 111 CCD unit 109 Character size recognition unit 113 Character size conversion unit 119 Distance measuring unit

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[Procedure amendment]

[Submission date] December 14, 1999 (1999.12.
14)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

According to an aspect of the present invention, there is provided an image processing apparatus comprising: an acquisition unit configured to acquire image data by capturing an image of an imaging target;
The image processing apparatus includes a measuring unit that measures a distance to an imaging target, and a resolution determining unit that determines a resolution of image data acquired using the measured distance.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Preferably, the image processing apparatus includes a storage unit for storing a plurality of sizes of the object in advance, and a size determination unit for determining the size of the imaging target based on the acquired image data and the measured distance. And a correcting means for correcting the determined resolution based on the stored size of the object and the determined size of the imaging target.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

According to another aspect of the present invention, an image processing apparatus includes: a storage unit for storing a plurality of object sizes in advance; an acquisition unit for acquiring image data by imaging an imaging target; Measuring means for measuring the distance, size determining means for determining the size of the imaging target based on the acquired image data and the measured distance, and the imaging target determined based on the size of the stored object Correction means for correcting the size of the object.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

According to the present invention, the resolution of the acquired image data can be determined. Furthermore, it is also possible to identify the size of the character drawn on the imaging target based on the determined resolution.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

<Third Embodiment> In the digital camera according to the third embodiment, the processing shown in FIG. 15 is executed instead of the processing shown in FIG. FIG.
Processing in step S301～S3 09 shown in 5,
Is the same as the processing in step S201～S2 09 in FIG. 14, description thereof will not be repeated here. In the digital camera according to the third embodiment, in step S311, the size of the document image is determined based on the plurality of standard paper sizes, and the resolution is determined based on the standard paper size and stored. . Then, in step S9 (see FIG. 4), resolution conversion is performed based on the stored resolution so that the output image has the same size as the imaging target, and the image is printed. As a result, the size of the text
Is output in the same size as.

Claims (5)

[Claims] An acquisition unit configured to acquire an image by capturing an image of an imaging target; a measurement unit configured to measure a distance to the imaging target; and a measurement unit configured to calculate a distance to the acquired image using the measured distance. An image processing apparatus comprising: a resolution determining unit that determines a resolution. 2. A storage unit that stores a plurality of object sizes in advance; a size determination unit that determines the size of the imaging target based on the acquired image and the measured distance; and the stored object. The image processing apparatus according to claim 1, further comprising: a correction unit configured to correct the determined resolution based on the size of the image capturing target and the determined size of the imaging target. 3. The image processing apparatus according to claim 1, further comprising an identification unit configured to identify a size of a character drawn on the imaging target based on the determined resolution. 4. A storage unit for storing a plurality of sizes of an object in advance, an obtaining unit for obtaining an image by imaging an imaging target, a measuring unit for measuring a distance to the imaging target, Size determining means for determining the size of the imaging target based on the obtained image and the measured distance; and correction for correcting the determined size of the imaging target based on the size of the stored object. With means,
Image processing device. 5. The image processing apparatus according to claim 2, wherein the object to be imaged is a document, and the storage unit stores a plurality of fixed sizes of the document.