JP2000278537A - Encoding system for image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently encode image data, in which plural kinds of images different in property coexist, for every image without computing a prediction error or the like. SOLUTION: When the image data of a medium read in an image reader 1 are sent to a position correction means 3, the position correction means 3 refers to position information indicated in the contents of a first table stored in a data base 2 and corrects the positions of the respective images inside the image data. Then, the corrected position information is sent to an encoding means 4 and thus, the encoding means 4 reads an encoding method corresponding to the kind of the image from a second table stored in the data base 2, encodes the image on the basis of it and stores it in a storage means 5 together with the position information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image encoding system for encoding image data of a medium having a plurality of types of images having different properties for each image.

[0002]

2. Description of the Related Art In recent years, an image of a medium read by an image reading device or an image created on a display is frequently transmitted between terminal devices such as personal computers. Because these images have a large amount of data and are highly redundant,
Processing without reducing the amount of information by entropy encoding the image, or processing that efficiently reduces and encodes information that can be reduced from human visual characteristics is performed I have.

[0003] As these encoding techniques, encoding of binary images for text-based document images generally used in facsimile and the like (ITU Recommendations T.4, T.6,
T. 82, etc., and techniques for encoding natural images such as color photographs (ITU recommendation T.81, etc.) are widely and generally known. By the way, images that are stored and transmitted using terminal devices in offices and the like are, for example, various licenses, passports, resumes, application forms, or document images mainly composed of characters as seen in product advertisements, etc. In many cases, the image data is image data of a medium in which images having gradations such as color photographs are mixed, that is, image data in which images having different properties are mixed.

When a plurality of types of images having different properties mixed on image data of one medium are encoded for each image, encoding of a binary image effective for the document image and color It has been considered to improve the encoding efficiency of the entire image data by combining an effective encoding method with a photograph or the like. As an example,
For example, a technique of dividing an image into a plurality of blocks, calculating a prediction difference for each block, and assigning effective coding by comparing the error value (Journal of Image Electronics Society of Japan, 131
No. 1997 VOL. 26 NO. 6 From page 708
716), and a technique of performing encoding while sequentially discriminating a character area and a dither area by using a context determination process performed at the time of encoding, assuming predictive encoding by a Markov model (The Institute of Image Electronics Engineers of Japan). Journal Vol. 124, 1996, Vol. 25, No. 5, pp. 533 to 540) has been proposed.

[0005]

However, in the above-mentioned prior arts, it is assumed that predictive coding is performed on divided blocks or regions.
Since it is necessary to calculate a prediction error and perform a comparison operation in order to assign an appropriate encoding method to each block or region, there is a problem that encoding takes a long time.

If the encoding suitable for a certain block or area is encoding that does not require calculation of a prediction error or comparison operation, computation for assigning an encoding method becomes burdensome, and furthermore, such as color photography, etc. For natural image areas,
When selecting an encoding (such as ITU recommendation T.81) that performs a process of effectively reducing the data amount from human visual characteristics,
Instead of predictive coding, operations such as discrete cosine transform and quantization are required, and there is a problem that the calculation of the prediction error becomes more burdensome.

The present invention provides an image encoding system capable of efficiently encoding image data in which a plurality of types of images having different gradations are mixed without performing an operation such as a prediction error. The challenge is to achieve.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides an image reading apparatus which reads a medium having a plurality of types of images having different properties at predetermined positions as image data, and reads the read image data. In the image encoding system for encoding for each image,
A first table in which position information of each image on the medium and information indicating the type of image are associated with each other, and a second table in which the type of image and an encoding method for encoding the image are associated with each other. Receiving the image data output from the image reading device, recognizing the position and type of each image on the medium corresponding to the image data based on the contents of the first table, Encoding means for encoding each image in the data by the method specified by the second table; and encoded data storage means for storing the data encoded by the encoding means together with the position information of the image. It is characterized by having.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an image encoding system according to the present invention. In FIG. 1, reference numeral 1 denotes an image reading device (image scanner);
Is a database, 3 is a position correcting means, 4 is an encoding means,
Reference numeral 5 denotes a storage unit.

The image reading device 1 is a device that optically reads a medium such as various types of licenses, passports, resumes, application forms, and outputs the image data. The database 2 includes a first table corresponding to position information of each image and information indicating the type of image for each type of medium,
The image processing apparatus has a second table in which the types of the images are associated with the encoding methods for encoding the images.

When there is a shift between the position of each image defined on the medium and the position of the image when the medium is read by the image reading device 1, the position correcting means 3 calculates and corrects the shift by calculation. The value is calculated. The encoding means 4 comprises a plurality of encoders for performing encoding according to the type of image such as a character or a color photograph, and the storage means 5 stores information of an image encoded by the encoding means 4. Is what you do.

FIG. 2 is a diagram showing an example of a medium to be read by the image reading apparatus 1. In the figure, reference numeral 11 denotes a medium. Reference numerals 12a to 12f denote image areas separately provided at predetermined positions on the medium 11, and characters are written in these image areas 12a to 12f by a form submitter, photos are pasted, or The seal has been made.

That is, addresses, names, telephone numbers, and offices are written in the image areas 12a to 12d, a seal is stamped in the image area 12e, and a face photograph is pasted in the image area 12f. ing. Reference numeral 13 denotes an image area printed in advance, in which notes regarding the medium and guidance items explaining the entry place are written.

Of these, addresses, names, telephone numbers, offices, seals and the like are character images printed or printed by hand, and these images are binary images or background images even if they are multi-valued images. This is an image having many foregrounds and a small number of intermediate gradations, that is, an image having the same pixel value and having a small number of prediction errors.
TU Recommendation T. 4, T. 6, T. 82, etc.), for example, MH,
Apply MR, MMR, JBIG, etc.

On the other hand, an image such as a certification color photograph is an image having a strong randomness and a large number of halftones. Such as encoding of natural images (ITU recommendation T.81 etc.), for example, JPEG
Are suitable. In addition, the medium 11 includes the medium 1
Although identification information such as a pattern and a mark (not shown) for specifying one type is provided, this identification information may be provided in the image area 13 in place of the above-mentioned cautionary notes.

In this embodiment, each of the image areas 12a
By switching the encoding method to be applied according to the properties of the image of ~ 12f, a more efficient encoding is selected,
The present invention realizes efficient encoding with a small number of operations, and the operation of the above-described configuration will be described below. First, the medium 11 shown in FIG. 2 is read by the image reading device 1, and the image data is sent to the position correction unit 3.

The position correcting means 3 determines the type of the form from identification information such as a pattern or a mark at a predetermined position of the image data on the medium 11 and, based on the result of the determination, from the first table of the database 2. The position information of each of the image areas 12a to 12f on the medium 11 is read. FIG. 3 is a diagram showing an example of the contents of the first table in this case.

As shown in FIG. 1, each item area 31a
The positions of the respective image areas 12a to 12f are described as coordinates in the position information areas 32a to 32f corresponding to. For example, the position information area 32a corresponding to the item area 31a, the position of the image region 12a corresponding to the item name is, the upper left coordinates (x _11, y _11), the lower right coordinates (x _12, y
₁₂ ), and the position of each image area is indicated by such a method.

The position information read from the database 2 accurately indicates the position of each area when the upper left and lower right positions of the image data of the medium 11 from the image reading device 1 are not shifted. However, when the image of the medium 11 is read by the image reading device 1, a displacement often occurs.

The position correcting means 3 stores the position information of the first table in the database 2 and the medium 11 actually read.
The position corrector 3 performs position correction, and outputs the corrected position information to the encoder 4. FIG. 4 shows an example of the corrected position information.

Item areas 41a to 41 in FIG.
f corresponds to the item areas 31a to 31f in FIG.
The position information of the position information areas 42a to 42f is obtained by performing a correction operation on the position information of the position information areas 42a to 42f in FIG. For example, a _x image data to the right of the medium 11, if the offset a _y below, with respect to the position information area 42a of the item area 41a, the position of the area, the upper left coordinates _{(x 11 + a x, y} 11 + A _y ) and lower right coordinates (x ₁₂ + a _x , y ₁₂ + a _y ).

The position of the image area in the image data of the medium 11 is accurately indicated by the corrected position information. This position correction is not directly related to the present invention and will not be described in further detail. For example, an identification mark indicating the type of the medium is provided on a part of the medium 11 and the shape of the mark is determined. For example, a method of identifying the medium 11 from information such as color and color, calculating the position shift of the image data based on the position shift, and using the image data as correction data can be considered.

In the present embodiment, it is possible to use a method that has already been realized as a subset of a character recognition device for image data, a seal identification device, or the like. The encoding unit receives the position information corrected by the position correction unit 3 and the image data from the image reading device 1 and encodes an image for each image area. Here, the encoding means 4 has a plurality of encoders in accordance with the image characteristics of each of the image areas 12a to 12f such as the binary image encoder and the natural image encoder. Item areas 41a to 41
Referring to the second table of the database based on the type of image identified from the information of f, information specifying the optimal encoding method is read out, and encoding is performed by the corresponding encoder.

The encoded information is stored in the storage means 5. FIG. 5 is a diagram showing an example of a storage format of information after encoding the image of each area. The item area 51a in FIG. 5 corresponds to the item area 31a in FIG. 3 and the item area 41a in FIG.
The position information a indicates the position after the correction, and corresponds to the position information in the position information area 42a in FIG.

A coded information storage area 53a is provided correspondingly to the coded information storage area 53a.
The encoded information is stored in 3a. Although only the item area 51a, the position information area 52a, and the coded information storage area 53a corresponding to the image area 12a are shown here, these item area, the position information area, and the coded information storage area are different from the other image areas 12b. The information is also provided continuously for the images of 12f to 12f.

To decode the encoded information, the decoding method is uniquely determined from the information in the item area 41a, and after the information stored in the encoded information storage area 53a is decoded, the position information area 52a is decoded. Based on your location information,
By arranging and displaying them on a display screen (not shown), image data of the original medium is generated. This decoding can be performed by the encoded device as needed, and can also be transmitted from the encoded device to another device and decoded by the destination device. It is possible.

In the above-described embodiment, the encoded information is stored in a continuous address space.
For example, as in the TIFF file format proposed by Adobe Systems Incorporated, the present invention can be applied to any of the storage methods using direct and indirect designation mixed by tags. Also, regarding how to specify the position of the image,
In the above-described embodiment, one set of upper left coordinate and lower right coordinate is used. However, it is also possible to specify one set of lower left coordinate and upper right coordinate, and four corners of upper left, lower left, upper right, and lower right are used. Any of the methods of designating the coordinates of any of the above and the size of the feeding roller in the writing area by the number of pixels in the vertical and horizontal directions can be used.

[0028]

As described above, according to the present invention, a medium in which a plurality of types of images having different properties exist at predetermined positions is read as image data by an image reading device, and the read image data is read by the image reading device. In an image encoding system that encodes each image, a first table that associates position information of each image on the medium and information indicating an image type, and encodes the image type and the image Receiving the image data output from the image reading device and the position of each image on the medium corresponding to the image data and the type of the image in the first table. , And encodes each image in the image data by the method specified by the second table. It is the things.

Therefore, according to this, it is possible to easily select an encoding method as compared with a method of switching prediction means by calculating a prediction error or the like, and to select a plurality of encoding methods having different gradations in image data of a medium. In addition to being able to encode various types of images at high speed and with high efficiency, the operation is hardly performed, so that the burden on the system is reduced. This is effective in encoding image data of a medium using a fixed document such as a license or image data of a medium having mixed multi-valued images including seal image data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a medium.

FIG. 3 is a diagram showing an example of the contents of a first table.

FIG. 4 is a diagram showing corrected position information.

FIG. 5 is a diagram showing a storage format of encoded information.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image reading apparatus 2 Database 3 Position correction means 4 Encoding means 5 Storage means

Claims (3)

[Claims] An image reading apparatus reads a medium in which a plurality of types of images having different properties exist at predetermined positions as image data, and encodes the read image data for each of the images. A first table in which position information of each image on the medium and information indicating an image type are associated, and an encoding method for encoding the image type and the image is associated. Receiving a second table and image data output from the image reading device, recognizing a position and an image type of each image of a medium corresponding to the image data based on the contents of the first table; Encoding means for encoding each image in the image data by a method specified by a second table; Encoding system of the image, characterized in that a coded data storage means for storing the encoded data together with the position information of the image by the step. 2. An image reading apparatus reads, as image data, a medium in which a plurality of types of images having different properties exist at predetermined positions, and codes the read image data for each image. A first table in which position information of each image and information indicating an image type are associated with each other for each type of medium, and an encoding method for encoding the image type and the image. Receiving the second table and the image data output from the image reading device, identifying the type of the medium by the identification information included in the image data, and determining the position of each image on the identified medium. The type of the image is recognized based on the contents of the first table, and each image in the image data is designated by the second table. An encoding system for an image, comprising: encoding means for encoding in accordance with the method described above; and encoded data storage means for storing data encoded by the encoding means together with position information of the image. 3. The image processing apparatus according to claim 1, wherein when the position of the image data output from the image reading device is shifted, the position information of the image in the first table is corrected and the correction is performed. An image encoding system comprising: a position correcting unit that notifies the encoding unit of the position information.