JP2003204435A - Data compression equipment, program and data restoring equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable compression and restoration of an image read by image reading equipment while lack of line data is prevented and space resolution information is preserved. <P>SOLUTION: Level conversion wherein picture element effective bits N are reduced to picture element effective bits I in the level direction is performed to picture elements of input line data DI, and intermediate line data DM are produced (Fig 1 (a), (b)). Packing conversion wherein elimination is performed except the picture element effective bits I and mutual picture elements of the picture element effective bits I are subjected to packing is performed to picture elements of the intermediate line data, and output line data DO are produced (Fig. 1 (c)). The output line data DO are transferred to restoring equipment and restored by the restoring equipment side, and restored line data B are produced (cf. Fig 1 (d)). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data compression apparatus suitable for compressing image data read by an image reading apparatus such as an image scanner, a program for causing a computer to realize the functions of the data compression apparatus, and a data compression apparatus generated by the data compression apparatus. And a data decompression device for decompressing compressed data.

[0002]

2. Description of the Related Art Generally, an image scanner is used as a device for reading a document such as a photograph or a picture as an image.
The image scanner is roughly classified into three types, that is, a flatbed type, a sheet feed type (automatic paper feeding type), and a handy type according to the reading method of the original.
The flatbed type and sheet feed type are both
When a document is set on the device, the device reads an image at a speed controllable by the device. The flatbed type scans an original by placing it on a flat table, and the sheet feed type scans the original by feeding it with rollers. On the other hand, the handy type is read by the user manually moving the document over the document.

Each of these scanners irradiates a document with light and determines the lightness (shade) of the reflected light by a CCD (Char.
ge Coupled Device) and CIS (Constant Image Sens)
o) and so on. The reading unit of these scanners is a line unit obtained by horizontally dividing a document. Therefore, CCDs and CISs also use those in which fine sensors are aligned.

FIG. 12 is an external view of an example of a handy type scanner. The scanner 100 shown in the figure has a form in which it is connected to an information processing device (not shown) such as a personal computer via a PC card 140.

The scanner 100 includes a scanner section 110, a cable 120, a connector section 130 and a PC card 140.
Is equipped with. The scanner unit 110 has a substantially rectangular parallelepiped or cylindrical shape, and one side surface in the longitudinal direction thereof is an image reading surface 111a. This surface 111a is a surface that comes into contact with a document sheet (not shown) when reading an image. Yes,
An image reading unit 112 and a movement amount detection unit 113 are provided.

The image reading section 112 is for optically reading an image on a document sheet, and is a light source for irradiating the document sheet with light (for example, an emitting diode and a cold cathode tube).
A light receiving element (CCD, CIS, etc.) that receives the reflected light from the original sheet and converts it into image data, and a mirror (in the case of CCD) or a lens for allowing the reflected light to enter the light receiving element. (In the case of CIS) and the like.

The movement amount detection unit 113 detects the movement amount of the image reading unit 112 on the original paper when the image is read. The movement amount detection unit 113 includes a rotating roller (not shown) and a rotary encoder (not shown) attached to the rotating roller. A part of the rotation roller is projected from the image reading surface 111a and is rotatably provided. When the image reading surface 111a is brought into contact with the original sheet and the scanner unit 110 is moved, the rotation roller causes the original sheet to move. The scanner unit 11 while contacting the paper
It is designed to rotate with the movement of 0. The rotary encoder outputs a movement amount detection pulse signal every time the rotation amount of the rotating roller reaches a predetermined amount. in this way,
When the scanner unit 110 is moved while abutting the image reading surface 111a on the original sheet, the rotary encoder detects the relative movement amount of the image reading section 112 with respect to the original sheet.

A start interruption instruction section 114 is provided on the surface of the scanner section 110 facing the image reading surface 111a. The start interruption instruction unit 114 is, for example, a push button type switch, and is turned on / off each time the button is pressed. When the switch is pressed first, the start interruption instruction unit 114 is turned on and the scanner 100 is activated to start reading a document. Becomes

A cable 120 to which a connector section 130 for a PC card 140 is connected is attached to the bottom of the scanner section 110. The PC card 140 is a card-type slot that is inserted into a PC card slot of an information processing device (not shown), and a connector portion to which the cable 120 is connected on one side surface (first side surface). Thirteen
A first interface 140a to which 0 is connected is provided, and a second interface 140b which is connected to the information processing apparatus in the PC card slot is provided on the other side surface opposite to the first side surface. . Also, PC card 1
A reading control unit, which will be described later, is provided in the unit 40.

The image reading unit 112 sequentially reads an image of one line of the original sheet by using a drive signal input from the reading control unit at a constant cycle T as a trigger, and outputs the image as image data to the reading control unit. . The image reading unit 112
Image data for one line is processed within the fixed period T.

In the handy type scanner 100 having the above structure, in order to reliably transfer the image data read by the image reading section 112 to the information processing apparatus, the data transfer speed between the information processing apparatus and the handy type scanner 100 is set in accordance with the data transfer rate. An image holding unit is provided in the reading control unit in the PC card 140.

By the way, the above handy type scanner 100
In the above, since the user manually moves the scanner unit 110 when reading the image on the document sheet, the scanner unit 110 may often be moved faster than the constant period T. In such a case, the image reading unit 112 moves two lines or more of the original within the fixed period T, and the image reading unit 112 cannot process image data other than the first line. For this reason, an image omission of one line or more occurs partially in the reading of the image of the document. In such a case, there arises a problem that an image finally generated on the information processing device side shrinks in the scanning direction.

Therefore, an invention (conventional invention 1) for solving this problem has been filed as Japanese Patent Laid-Open No. 2000-349984. This publication discloses an image reading apparatus including an image data generation unit that generates image data according to the amount of movement of the scanner unit detected by the movement amount detection unit. When it becomes faster than the cycle of the drive signal in the data processing unit, by copying the image data of the portion according to the movement amount, there is no shrinkage in the scanning direction without being affected by the movement speed of the scanner unit. A technique capable of obtaining an image is disclosed.

Further, in order to increase the resolution in the main scanning direction of the image reading device (handheld scanner 100), I of the image reading device is used.
/ F (second interface 140 of PC card 140
If the data transfer rate between b) and the information processing device cannot keep up, it is necessary to provide a buffer in the reading control unit to temporarily hold all image data read by the image reading unit 112. As a result, the capacity of the buffer increases and the manufacturing cost of the image reading apparatus increases.

Therefore, the applicant of the present invention proposes, as an invention for solving such a problem, Patent Application No. 2001-91084.
The invention (conventional invention 2) was filed first. This Conventional Invention 2
FIG. 13 is a block diagram showing the functional configuration of the image reading apparatus of FIG.
FIG. 14 shows the operation time chart thereof. For the sake of convenience, in FIG. 13, the reference numerals of the image reading system, the image reading apparatus, and some functional blocks are shown in Patent Application No. 20.
It is different from the drawing of 01-91084. The reference numerals of the functional blocks and the devices whose reference numerals are changed are as follows. The reference numerals in parentheses are the reference numerals of the application drawings.

Image reading device 150 (10) ... Data processing device 141 (31) ... Reading control unit 142 (102) ... Image signal processing unit 143 ( 33) ... I / F section 151 (101) ... Transfer data generation section 152 (102) ... Data compression section 153 (103) ... Transfer state detection section 154 (104) ... Switching Part 200 (40) ... Information processing device 300 (100) ... Image reading system In the conventional invention 2, the image reading device 100 includes a scanner unit 110 and a data processing unit 150. The scanner unit 110 includes an image reading unit 112 and a movement amount detection unit 113. In addition, the data processing unit 1
Reference numeral 50 includes an image signal processing unit 142, a reading control unit 141, and an I / F unit 143. The read control unit 141 also includes a transfer data generation unit 151 and a data compression unit 15.
2. The transfer state detection unit 153 and the switching unit 154 are included.

In the image reading unit 112, the drive signal S2 (see FIG. 14B) input from the reading control unit 114 at a constant cycle T (T1, T2, ... Images for one line are sequentially read, and the image data D1 (D1-1, D1-2, ... D1-
9) to the image signal processing unit 142 (FIG. 14).
(See (c)). The image data D1 is analog data for one line of the original paper. Image signal processing unit 142
Is the binarized image data D2 of the input image data D1.
It is converted to (D2-1, D2-2, ..., D2-3) and output to the transfer data generation unit 151 (see FIG. 14D).

The moving amount detecting section 113 has a pulse-like moving amount detecting pulse signal S1 every time the rotary roller rotates by a certain angle.
(S1-1, S1-2, ..., S1-9) is output to the transfer data generation unit 151 (see FIG. 14A). The transfer data generation unit 151 receives the movement amount detection pulse signal S1 from the movement amount detection unit 113 of the scanner unit 110 (see FIG. 14E) every time the binarization is input from the image signal processing unit 142. The transfer data D3 including the image data D2 and the movement amount M (the number of movement amount detection pulse signals S1 input from the movement amount detection unit 113 within the driving cycle T) is output to the switching unit 154 (FIG. 14 (f). )reference). The transfer data D3 is temporarily stored in a storage unit (not shown).

The data compression unit 152 generates transfer data D3 generated by the transfer data generation unit 151 and stores the transfer data D3 other than the specific transfer data D3 for each of a plurality of continuous transfer data D3. And the moving amount M included in the thinned transfer data D3 is added to the moving amount M included in the specific transfer data D3 to add the image data included in the specific transfer data D3 and the addition. Compressed data D4 including the moved amount M
(D4-1, D4-2) is generated, and it is switched to the switching unit 154.
(See FIG. 14 (g)).

The transfer state detecting unit 153 detects the transfer speed of the I / F unit 143 by measuring the input speed and the output speed per unit time in the line buffer, and outputs the detection result to the switching unit 154. To do.

The switching unit 154 selects either the transfer data D3 generated by the transfer data generation unit 151 or the compressed data D4 generated by the data compression unit 152 according to the detection result detected by the transfer state detection unit 153. One of them is output to the I / F unit 143. In this case, if the input / output speed in the line buffer is slower than a preset speed, it is determined that the transfer speed is slow,
Compressed data D4 generated by the data compression unit 152
Is output to the I / F unit 143 (compressed transfer mode). On the other hand, when the input / output speed in the line buffer is equal to or higher than the preset speed in the detection result, it is determined that the transfer speed is high, and the transfer data generation unit 151
The transfer data D3 generated by is transmitted to the I / F unit 143 (normal transfer mode).

When the information processing apparatus 200 receives the transfer data D3 or the compressed data D4 from the I / F section 143,
The amount of movement M added to the image data is obtained, and the image data is copied (M-1) times so that the image data has the same number as the amount of movement M. Restore.

FIG. 14 is a diagram for explaining a method of restoring the transfer data D3 transferred in the normal transfer mode shown in FIG. 14 (f) on the information processing device 200 side. Figure 15
Binarized image data D2 (D2-1, D shown in (a)
2-2, ..., D2-7) and the amount of movement M corresponding to each of the binarized image data D2 are the transfer data generation unit 151.
The binarized image data (A-1, A shown in FIG.
-2, A-4, A-7) and the amount of movement M corresponding to each of the binarized image data, four pieces of transfer data D3
-1. It is converted into D3-2, D3-3 and D3-4.

The information processing apparatus 200 converts the four transferred data D3 transferred from the I / F unit 143 into the restored image data B (6 lines) of 6 lines as shown in FIG. B-1, B-2, ..., B-6). In this case, the binarized image data A-2 (binarized image data of the second line) of the transfer data D3-2 is set to 2
It is copied twice and the restored image image data B-3 of the third line
And the restored image data B-4 of the fourth line is restored.

Next, FIG. 16 is a diagram for explaining a method of decompressing the compressed data D4 transferred in the compression transfer mode shown in FIG. 14 (g) on the information processing apparatus 200 side. In this figure, (a) and (b) are the same as those in FIGS. 15 (a) and 15 (b) described above, and therefore their description is omitted. In the compression transfer mode, the two pieces of compressed data D4-1 and D-2 shown in FIG. 16C are transferred to the information processing device 200. The compressed data D4-1 is composed of the binarized image data A-1 and the movement amount "4", and the compressed data D4-2 is composed of the binarized image data A-2 and the movement amount "2". The information processing apparatus 200 uses the two pieces of compressed data D4-
1 and D4-2 are received, the binarized image data (A-1, A-2) included in those compressed data are moved by the moving amount M (“4”, which is also included in those compressed data,
According to the value of "2"), the restoration is performed as shown in FIG.

That is, in this case, 2 to 4 are obtained by copying three pieces of the binarized image data A-1 of the first line.
Binarized image data (B-2 to B-4) on the 6th line is restored by restoring the binarized image data on the 4th line (B-2 to B-4). Restore -6.

As described above, in Conventional Invention 2, the normal transfer mode is performed while comparing the data transfer rate of the I / F unit 143 and the amount of transfer data D3 generated per predetermined unit time on the image reading device side. By switching between the transfer data D3 and the compressed data D4 by switching between the transfer mode and the compressed transfer mode, two-dimensional image data without compression can be read by the decompression side with a small capacity line buffer. Image data was transferred (data transfer speed improvement method by thinning line data).

[0028]

As described above, in the conventional invention 2, the data compression is performed by thinning out the image data of one or a plurality of lines so that the spatial resolution information is lost and the amount of the transfer data D3 to be generated is reduced. If the I / F unit 143 cannot keep up with the data transfer rate, the mode is switched to the compression transfer mode and the compressed data D4 generated by the data compression is transferred to the information processing apparatus 200 (FIG. 14 (g)). reference). Here, the spatial resolution information is the resolution of pixels forming a two-dimensional spatial image.

However, according to the method of the conventional invention 2, there is no problem when the human visually confirms the read image data. For example, the two-dimensional code 400 as shown in FIG. When the data is read by 100, part of the spatial resolution information is lost due to the line data being thinned out, so that the black-and-white point cannot be correctly decoded on the restoration side, and the decoding rate of the two-dimensional code decreases. As a result, there arises a problem that restoration is hindered.

The two-dimensional code includes the image data, URL (Uniform Resourace Locator), and M shown in FIG. 17 (b).
Information such as various kinds of multimedia data such as IDI (Musical Instrumental Digital Interface) data, and further, text data and the like are printed as white and black dots.

As described above, according to the method of the conventional invention 2, when the spatial resolution information such as the two-dimensional code is transferred with a part missing, it is possible to compress the data of the code which causes a trouble in the restoration of the original data on the restoration side. Was inappropriate.

The present invention compresses data such as an image and a code read by an image reading apparatus by a data compressing apparatus, a data compressing method, a data compressing apparatus and a data compressing method capable of compressing data while storing spatial resolution information. Data restoration device and data restoration method capable of restoring stored data,
An object of the present invention is to provide a computer-readable recording medium recording a program and a program.

[0033]

The data compression apparatus according to the first aspect of the present invention is premised on a data compression apparatus for compressing line data read by image reading means for reading an image of an original in line units.

The data compression apparatus of the first aspect inputs the digitized line data, and generates the intermediate line data in which the effective bits of each pixel of the line data are reduced in the level direction. Image data generation means,
A second image data generation unit that deletes bits other than valid bits from each pixel of the intermediate line data to generate output line data in which pixels having only valid bits are packed.

According to the data compression apparatus of the first aspect, since the bit of the pixel of the line data is reduced in the level direction to compress the line data, the line data can be compressed while the spatial resolution information is stored. .

A data compression apparatus according to the second aspect of the present invention is
In addition to the above-mentioned means included in the data compression apparatus of the first aspect, further, a data transfer rate detecting means for detecting a data transfer rate of an interface for transferring the output image data, and the image reading means for reading per unit time. When the data transfer rate indicating the generated amount of data to be compared with the data transfer rate detected by the data transfer rate detecting means and the data transfer rate is evaluated to be slower than the data amount transfer rate, The first image data generation means and the second image data generation means are provided with a transfer speed evaluation means for notifying the effective bit number, and the first image data generation means and the second image data generation means are provided. , Only when the transfer rate evaluation means evaluates that the data transfer rate is slower than the data generation rate. And between the line data and generates the output line data.

According to the data compression apparatus of the second aspect, the data generation rate on the image reading means side and the data transfer rate on the interface side are compared to determine whether or not compression is required at the present time, and compression is required. Since input line data is compressed and transferred only when it is determined, unnecessary compression can be avoided,
The compressed data can be transferred to the decompression side only when compression is necessary, and the input line data can be directly transferred to the decompression side when compression is unnecessary.

A data compression apparatus according to the third aspect of the present invention is
In addition to the means provided in the data compression apparatus of the first aspect, a signal indicating the movement amount of the image reading means is further input, the movement speed of the image reading apparatus is detected from the signal, and the movement speed When the driving speed of the image reading means is compared and it is evaluated that the moving speed is faster than the driving speed, the effective bit is added to the first image data generating means and the second image data generating means. The first image data generation means and the second image data generation means are evaluated by the movement speed evaluation means as the movement speed being faster than the drive speed. Only in the case of the above, the intermediate line data and the output line data are respectively generated.

According to the data compressing device of the third aspect, the moving speed of the image reading means and the driving speed are compared to judge whether the compression is necessary at the present time. Only when it is judged that the compression is necessary, the input line data is inputted. Is compressed and transferred, wasteful compression can be avoided, compressed data can be transferred to the decompression side only when compression is necessary, and input line data can be transferred to the decompression side as it is when compression is unnecessary.

The data restoration device of the present invention responds to the input line data by level conversion for reducing the bits of the pixel of the input line data in the level direction and the number of bits of the pixel reduced by the level conversion. It is premised on a data decompression device that decompresses compressed line data generated by performing packing conversion for packing the pixels.

This data decompression device performs unpacking conversion on the compressed line data to restore the pixels of the compressed line data to the pixels before the level conversion, and decompresses the line data before the level conversion. And a generation unit for converting the level of the pixel of the line data generated by the restoration unit to generate line data including a pixel of a predetermined bit.

According to the above data decompression device, the line data compressed by the level conversion and the packing conversion are
It is possible to restore to line data suitable for various applications.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for generally explaining the principle of an embodiment of a data compression / decompression method of the present invention. This figure shows 4-line input line image data (input line data) DI (DI-1, DI-2, DI-3, D).
This is an example of compressing / restoring I-4). The number of bits of each pixel of the input line data DI (pixel effective bit) is N
(For example, N = 8) (see (a) in the figure).

First, the level conversion of each pixel of the input line data DI of these four lines is performed, and the effective bit number of each pixel is reduced from N bits (for example, N = 8) to I bits (for example, I = 4). Intermediate line data DM (DM-
1, DM-2, DM-3, DM-4) (see (b) of the same figure).

In the present invention, the effective bit number I in the bit string indicating the pixel value (level such as gradation value) is defined as "level information". Further, a bit string of these I bits is defined as a pixel effective bit I. Furthermore, from the MSB (Most Significant Bit) of the bit string indicating the pixel value to the LSB.
The direction to (Least Significant Bit) is defined as the level direction. Further, the operation of converting the number of bits of the pixel effective bit I is defined as level conversion. In the image data compression of the present invention, “to reduce the number of bits in the level direction, the pixel effective bit N is changed to the pixel effective bit I (I <
The level conversion for converting into N) is performed. It should be noted that in the case of data restoration which will be described later, level conversion with I ≦ N is performed.

Next, the packing conversion is performed and the intermediate line data DM (DM-1, DM-2, DM-3, DM-).
4) to output line data (compressed line data) DO
(DO-1, DO-2, DO-3, DO-4) is generated (see (c) in the figure).

This packing conversion expresses the value of the pixel by the pixel effective bit I by deleting the bits other than the pixel effective bit I of the pixel of the intermediate line data DM, and consists of only the pixel effective bit I. This is an operation of packing pixels in the pixel arrangement order (the main scanning direction of line data).

By this packing conversion, output line data DO is generated from the intermediate line data DM. In the case of the pixel valid bit N (N = 8) of the input line data DI and the pixel valid bit I (I = 4) of the intermediate line data,
Due to the packing conversion, the input line data DI is compressed into output line data whose data amount is 1/2.

The output line data DO is transferred together with level information (the number of pixel effective bits I, that is, I = 4) to a restoration device such as an information processing device, and the restoration line data B (B- 1, B-2, B-3,
B-4) is restored (see (d) of the same figure). The valid bit M of the pixel of the restored line data B generated by this restoration is 8 bits, which is the same as the pixel valid bit I of the pixel of the input line data DI. Therefore, the data length of both data is the same.

As described above, in the data compression method of this embodiment, when compressing the input line data DI, the packing unit is switched according to the level conversion of the pixel and the number of bits of the pixel reduced by the level conversion. In this way, by compressing the input line data DI by compressing the level information of pixels in the level direction, the input line data D
I can be compressed while preserving its spatial resolution information. Therefore, it is suitable for compression of data, such as a two-dimensional code, in which lack of spatial resolution information hinders restoration.

FIG. 2 is a block diagram of data compression / execution according to the embodiment of the present invention.
It is a figure which pays attention to the pixel of input line data DI, intermediate line data DM, output line data DO, and restoration line data B, and explains the principle of a restoration method. In the figure, the number of pixel effective bits N of the input line data is 8 bits (N = 8), and the level-converted intermediate line data DM
The number of pixel effective bits I is 4 bits (I = 8),
An example in which the number of pixel valid bits M of the output line data DO is (M = 8, 1) is shown.

FIG. 2 shows two pixels PI (PI-1, P-1).
For I-2), compression processing for sequentially performing level conversion and packing conversion, transfer of compressed line data generated by the compression processing (the above is processing on the compression side), and the compressed line data A decompression process of the compressed line data that sequentially performs unpacking conversion and level conversion is shown. Further, in the figure, two types of data restoration methods are shown.

First, a method of compressing image data will be described. In the compression, first, for the pixel PI-1 of the first pixel and the pixel PI-2 of the second pixel of the input line data DI (see (a) in the same figure), the upper 4 bits are set to 4 in the lower direction.
After bit-shifting, level conversion for setting "0" to the lower 4 bits is performed (see (b) in the same figure). In this case, the bit number (level information) I of the pixel effective bit I is "4". In addition, these pixels PI-1 and PI-2 are shown in FIG.
It is a pixel of the intermediate line data DM of (b).

Next, the lower 4 bits are deleted from the pixels PI-1 and PI-2, and packing conversion is performed to pack the upper 4 bits of the pixel PI-1 and the pixel PI-2, and compression of 8 bits is performed. Line data (packing data) DP
Is generated (see FIG. 2C). With such a compression method, the input line data DI is converted into output line data (compressed line data) DP having a data amount of 1/2 (see FIG. 1C). Then, this compressed line data D
P is transferred to the restoration device side (see FIGS. 2D and 2G).

The host machine uses the compressed line data DP
When you receive. Then, unpacking conversion and level conversion are applied to the line data to restore the line data. here,
First, the first embodiment of the image data restoration method for restoring the pixels of the pixel effective bit M of the restored line data B to the same number M of bits as the pixel effective bit M of the pixels of the input line data DI will be described with reference to FIG. )-(F).

First, as shown in FIG. 9D, unpacking conversion is applied to the compressed line data DP. In this unpacking conversion, a conversion opposite to the packing conversion is performed based on the level information (in this case, I = 4 bits), and one pixel obtained by the level conversion shown in FIG. Eye data (level conversion data) PL
-1 and second pixel data (level conversion data) PL-2
Is restored (see (e) in the figure).

Then, as shown in FIG. 7E, the restored data PL-1 of the first pixel and data P-1 of the second pixel are restored.
Level conversion is performed on L-2, and restored pixel data PLR-1 and PLR-1 of the first pixel of M bits (pixel effective bit M).
The restored image data PLR-2 of the pixel is generated (see (f) in the figure). In the level conversion processing shown in (e) of the figure, the right 4 bits (lower 4 bits) of the pixel data PL-1 and PL-2 are shifted by 4 bits in the upper direction, and the lower 4
By setting "0" in the bit, 8-bit (M = 8) pixel data PLR-1 and PLR-2 shown in FIG.

In the image data restoration method of the first embodiment, restored pixel data PLR (PLR-1, PLR-2)
Is the same pixel data P of the input line data data DI
Restoration is performed so as to be represented by the same number of bits (same level) as the value of I (PI-1, PI-2). As a result, a gradation image or the like can be restored (generated).

Next, a second embodiment of the image data restoration method will be described with reference to FIGS. In this embodiment, binary pixel data is restored (generated). First,
The compressed line data DP shown in FIG. 9G is unpacked by the same method as in the first embodiment to restore the data PL-1 of the first pixel and the data PL-2 of the second pixel ( Refer to FIG. Subsequently, as shown in FIG. 6H, binarization processing is performed on these two pixel data PL-1 and PL-2, and the first pixel is "1" and the second pixel is "0". And And these two binarized ones
Bit (M = 1) pixel data is set to the first and second bits of the 8-bit restored image data PLR ′ (see (i) in the figure). In this binarization process, the quantization process is performed with the binary value “1000” (= 8) as the threshold value.

As described above, in the image data restoration method of the second embodiment, the pixels of the input line data DI that were multi-valued image data are restored to the binary image data of the pixel effective bit M (M = 1). . By the way, in both the unpacking conversion and the level conversion in the first and second image data decompression methods, the number of bits of the pixel effective bit I of the intermediate line data generated by the level conversion in the image data compression (I = Refer to 4-bit level information).

FIG. 3 is a block diagram showing the system configuration of an image reading apparatus including the first embodiment of the data compression apparatus of the present invention. The image reading device 1 shown in FIG. 1 includes a reading control unit 3 and a sensor unit 40. Sensor unit 40
Is an image sensor which reads image information as an optical signal, converts it into an electrical signal, and outputs image data of the image information.

The data processing section 3 comprises a data compression section 10, an image signal processing section 20 and an I / F section (data transfer section) 30. The image signal processing unit 20 and the I / F unit 30 have the same functions as the image signal processing unit 142 and the I / F unit 143 of FIG. 13, respectively, and detailed description thereof will be omitted here.

The data compression section 10 is the first embodiment of the data compression apparatus of the present invention, and comprises a level conversion image data generation section 11 and a packing data generation section 12. The level-converted image data generation unit 12 performs the level conversion process shown in FIG. 2B on the line data input from the image signal processing unit 20, and the pixel effective bit I obtained by the level conversion process. The intermediate line data composed of the pixel data of 1 is output to the packing data generation unit 12. The packing data generation unit 12 performs the packing conversion shown in FIG. 2C on the intermediate line data DI to generate the compressed line data DO. The I / F unit 30 transfers the compressed line data DO input from the packing data generation unit 12 to an information processing device (not shown).

FIG. 4 is a block diagram showing the system configuration of an image reading apparatus including the second embodiment of the data compression apparatus of the present invention. In the figure, the same names are given to the components having substantially the same functions as the components included in the image reading apparatus 100 shown in FIG. 13 described above.
Also, with regard to signals, signals having the same functions are denoted by the same reference numerals.

The image reading apparatus 2 shown in the figure comprises a scanner section 60 and a data processing section 50. Scanner unit 60
Includes an image reading unit 61 and a movement amount detection unit 62. The image reading unit 61 and the movement amount detecting unit 62 are the same as those in FIG.
Of the image reading unit 112 and the movement amount detection 113 of
Detailed description is omitted here.

The data processing unit 50 is the image signal processing unit 5.
2. Read control unit 52 and I / F unit (data transfer unit) 53
Equipped with. The image signal processing unit 52 and the I / F unit 53, and the image signal processing unit 20 and the I / F unit 30 of FIG. 3 described above, respectively.
It has the same function as.

The reading control unit 52 is the second embodiment of the data compression apparatus of the present invention, and is a level conversion image data generation unit 52a, packing data generation unit 52b, data speed detection unit 52c, transfer speed evaluation unit 52d and movement. Quantity evaluation part 5
2e. This reading control unit 52 is the second embodiment of the data compression apparatus of the present invention, and in addition to data compression,
The read control of the entire data processing unit 50 and the transfer data (compressed line data) to be transmitted to the information processing device 65 are transferred to the I / F unit 5.
It has a function to output to 3.

The data transfer rate detector 52c detects the transfer rate (data transfer rate) of the I / F section 53 and notifies the transfer rate evaluator 52d of the detection result tv. The data transfer rate detection unit 52c monitors, for example, the amount of data transferred from the I / F unit 30 to the information processing device 65 per unit time, and calculates the data transfer speed of the I / F unit 53 from the monitoring result. Then, the data transfer rate of the I / F unit 53 is detected. In addition to the method, the data transfer rate detecting unit 52c acquires, for example, the data transfer rate preliminarily specified as the specifications of the I / F unit 53 from the I / F unit 53 or the like, and then acquires the data transfer rate. Considered as the data transfer rate of. In an actual operating environment, the transfer rate (data transfer rate) between the I / F unit 53 and the information processing device 65 varies depending on the state of the information processing device 65, and so on. It is preferable to detect the data transfer rate.

The transfer rate evaluation unit 52d is, for example, based on the driving cycle (driving frequency) of the image reading unit 61 and the resolution per line of the image reading unit 61, the unit of the line data read by the image reading unit 61. The amount per time (data generation rate S) is calculated. Transfer rate evaluation unit 52
d compares the data generation speed S with the data transfer speed of the I / F unit 53, and determines whether the data transfer speed is slower than the data generation speed S. When the transfer rate evaluation unit 52d evaluates that the data transfer rate is slower than the data generation rate S, the level conversion image data generation unit 52a generates the image data generated by the image signal processing unit 51. (Line data of pixel effective bit N) When the level conversion processing is performed on D2, the optimum bit number I (level information) of the pixel effective bit I is determined, and it is determined by the level conversion image data generation unit 52a and packing data generation. Notify the section 52b. Further, at this time, the transfer speed evaluation unit 52d is configured so that the level conversion image data generation unit 52a
To the packing data generation unit 52b,
The level conversion and packing conversion instructions are also notified. still,
The notification of these instructions may be replaced with the notification of the information regarding the number of bits of the pixel effective bit I.

When the driving speed of the image reading unit 61 is high or the resolution per line (line resolution) of the image reading unit 61 is high, the number of line data read by the image reading unit 61 per unit time value. (Data volume) becomes large. Therefore, the data generation speed S increases. For example, in a flatbed scanner having an image reading unit with high line resolution or high driving speed,
The data generation speed S becomes faster. For this reason, the I / F unit 53 having a low data transfer speed may not be able to perform data transfer that can follow the data generation speed S of such a flatbed scanner. In the present embodiment, assuming such a case, the transfer speed evaluation unit 52d compares the data generation speed S with the data transfer speed of the I / F unit 53, and a line generated by the image signal processing unit 51. It is determined whether the data compression of the data D2 is necessary. Then, when the transfer rate evaluation unit 52d determines that the data compression is necessary, the transfer rate evaluation unit 52d instructs the level conversion image data generation unit 52a and the packing data generation unit 52b to operate, and causes the level conversion image data generation unit 52a and the packing data generation unit 52b to perform compression of the line data D2. The F unit 53 reduces the amount of data to be transferred to the information processing device 65.

When the level conversion image data generation unit 52a is notified of information such as the number of bits I (level information) of the pixel effective bit I together with the level conversion instruction from the transfer speed evaluation unit 52d, the above-mentioned FIG. ) Line data D2 (FIG. 1) received from the image signal processing unit 51 by the method shown in FIG.
Level conversion processing is applied to (corresponding to the input line data DI in (a)). Then, the level conversion image data generation unit 52a outputs the intermediate line data DM (see FIG. 1B) obtained by the level conversion processing to the packing data generation unit 52b. By the way, the level-converted image data generation unit 52 a has a line buffer 57 inside, and the line data D input from the image signal processing unit 51.
Save 2 to it temporarily.

The packing data generator 52b receives the packing conversion instruction from the transfer rate evaluator 52d,
After that, when the intermediate line data DM is received from the level conversion image data generation unit 52a, the transfer speed evaluation unit 52
Based on the bit number I (level information) of the pixel effective bit I notified from d, the intermediate line data DM is subjected to the packing conversion by the method shown in FIG. To generate. Then, the level information (pixel valid bit I
1) is added to generate output line data (compressed data) DO (see FIG. 1C), which is output to the I / F unit 53. The I / F unit 53 transfers the compressed data DO to the information processing device 65.

Further, the reading control unit 52 is based on the evaluation result of the movement amount evaluation unit 52e in addition to the evaluation of the transfer speed evaluation unit 52d, and in the same manner as above, the level conversion image data generation unit 52
The line data D2 generated by the image signal processing unit 51 is compressed by a and the packing data generation unit 52b.

Moving amount evaluation unit (moving speed evaluation unit) 52e
Calculates the moving speed of the image reading unit 61 based on the moving amount detection pulse signal S1 input from the moving amount detecting unit 62.
That is, for example, the input time interval of the pulse (encoder pulse) of the moving amount detection pulse signal S1 is measured, and the moving speed is calculated from the time interval and the moving amount of the image reading unit 61 per pulse. This moving speed corresponds to the speed at which the user moves the scanner unit 60 on the document.

Further, the movement amount evaluation section 52e obtains the driving speed of the image reading section 61 from the driving cycle of the image reading section 61. The drive speed may be calculated based on the pulse generation cycle of the drive signal S2 or may be calculated from the drive cycle defined by the specifications of the image reading section 61. When the movement amount evaluation unit 52e evaluates that the movement speed of the image reading unit 61 is faster than the driving speed of the image reading unit 61, the level conversion image data generation unit 52a performs the level conversion according to the speed difference. The number I of pixel effective bits I to be used at the time
(Level information) is determined and notified to the level conversion image data generation unit 52a and the packing data generation unit 52b. Further, the movement amount evaluation unit 52e instructs the level conversion image data generation unit 52a and the packing data generation unit 52b to perform the level conversion and the packing conversion, respectively. This instruction may be replaced by the notification of the level information. Further, in the present embodiment, the movement amount evaluation unit 52e has a function of detecting the drive speed of the image reading unit 61 from the movement amount detection pulse signal S1, but the movement speed detection unit having this function is read and controlled. The movement amount evaluation unit 5e is provided separately in the unit 52, and the movement amount evaluation unit 5e is provided.
2e may be configured to only compare and evaluate the moving speed (detected by the moving speed detecting unit) and the driving speed.

The level conversion image data generation unit 52a and the packing data generation unit 52b are notified of the above-mentioned operation execution instruction from the movement amount evaluation unit 52e, and then the transfer speed evaluation unit 52 is notified.
The same processing as when receiving the same notification from d is executed. As a result, the level conversion image data generation unit 52a
The level conversion image data generation unit 52a and the packing data generation unit 52b sequentially perform level conversion and packing conversion on the line data D2 stored in the line buffer 57 in the internal buffer 57, and finally, the packing data The generator 52b generates compressed data (output line data) DO. This compressed data DO
Is output from the packing data generation unit 52b to the I / F unit 53 and transferred to the information processing device 65 via the I / F unit 53.

The moving speed of the image reading section 61 is determined by the image reading section 6
When the user reads the image of the document with the handy-type scanner, the situation in which the driving speed exceeds the driving speed of 1 is the scanner unit 60.
Occurs when the image reading section 61 is moved at a higher speed than the driving speed of the image reading section 61. In such a case, a plurality of movement amount detection pulse signals S1 are output from the movement amount detection unit 62 within the drive cycle of the image reading unit 61. At this time, the level conversion image data generation unit 52a sets the line data read first in the drive cycle stored in the line buffer 57 as the movement amount detection pulse signal S1 in order to prevent the line data from being lost. The number (encoder pulse number) is duplicated to generate the same number of line data as the encoder pulse number. Therefore, the amount of image data generated per unit time increases, and the I / F unit 53 causes the information processing device 6 to output per unit time.
Amount of data to be transferred to the I / F unit 5 (I / F unit 53 is required to properly transfer data to the information processing device 65).
The data transfer rate of the F section 53 will increase. Normally, the I / F unit 53 is the image reading unit 61 of the scanner unit 60.
, Which has a data transfer rate that can handle the case where one line of data is read within the drive cycle,
As described above, when the moving speed of the image reading unit 61 exceeds the driving speed of the image reading unit 61, the amount of data that the I / F unit 53 should transfer to the information processing device 65 is the data transfer capability of the I / F unit 53. Will exceed. In the present embodiment, in order to prevent such a situation, a movement amount evaluation unit 52e is provided, and when the image signal processing unit 51 generates line data in an amount exceeding the data transfer rate of the I / F unit 53. Performs data compression by level conversion and packing conversion.

By the way, the reading control section 52 is triggered by the input of the movement amount detection pulse signal S1 from the movement amount detecting section 62 to be stored in the line buffer 57 in the level conversion image data generating section 52a by interrupt processing. The series of data transfer processing of the image data D2 stored is started.

FIGS. 5 and 6 are diagrams showing examples of the format of transfer data generated by the packing data generator 52b. The transfer data 70 shown in FIG. 5 includes header information 71 and transfer line data 72 (72-) of n lines.
, 72-2, 72-3, ..., 72-n). The header information 71 includes level information 71a,
It is composed of packing information 71b and line information A71c. This header information 71 is transferred to the information processing device 65 prior to the transfer line data 72.

The transfer line data 72 includes the level-converted image data generator 52a and the packing data generator 52b.
Line data compressed by (compressed line data)
Alternatively, it includes line data (non-compressed line data) that has not been compressed by them, and at the beginning thereof, for example, the line data included in the transfer line data 72 identifies either compressed line data or non-compressed line data. Information for doing so is set. Further, for example, the level information (pixel effective bit I (in the case of compressed line data) or pixel effective bit N (the number of bits of non-compressed line data)) is added.

The level information 71a is information indicating the number N of pixel valid bits N of the non-compressed line data and the number I of pixel valid bits I of the compressed line data. However, the pixel effective bit I of the compressed line data
The information indicating the bit number I of is set only when the pixel effective bit I at the time of level conversion of the line data D2 generated by the image signal processing unit 51 is constant (I / F
This is because the pixel valid bit I may be changed according to the state of the data transfer rate of the unit 82). When the level information 71a is set in the header information 71, only the identification information indicating that it contains the compressed line data is added to the beginning of the transfer line data 72 containing the compressed line data. It is also possible to add the level information of the compressed line data.

The packing information 71b is information indicating the type of packing conversion, and indicates the form of packing. In the present invention, the packing conversion is not limited to the method shown in FIG. 2C, but the type of data read by the scanner unit 60 (two-dimensional code, gradation image, color image, etc.) and pixels. Optimal packing conversion is applied to each of the effective bits I in accordance with the number I of bits.
The packing information 71b is information for allowing the restoration side to recognize these types of packing conversion.
On the restoration side, the unpacking conversion can be correctly performed based on the packing information 71b.

The line information A71c is information relating to the transfer line data 72, and is set with, for example, the total number of pixels of uncompressed line data and compressed line data included in the transfer line data 72. Further, when the size of the image to be read is known in advance such as a standard size original paper, the total number of transfer line data 72 and the like are also set.

The transfer data 75 of FIG. 6 is the header information 7
6, transfer line data 77 of n lines (77-1, 77)
, 77-3, ..., 77-n) and an END code 78. The header information 76 is level information 76a,
It is composed of packing information 76b and line information B76c.

The transfer data 75 differs from the transfer data 70 in that it has an END code 78 and that the line information B76c does not include the total number of line data 77 unlike the line information A71c. Others
Similarly, the transfer line data 77 can have the same configuration as the transfer line data 72.

The transfer data 70 shown in FIG. 5 and FIG.
Reference numeral 75 is only a part of the embodiment, and the transfer data generated in the present invention includes formats other than the above. For example, as schematically shown in FIG. 1C, each transfer line data includes output line data DO (compressed line data or uncompressed line data) and level information (pixel valid bit I or pixel valid bit N). The number of bits may be added.

As described above, in the present invention, the level information of each output line data DO and its pixels is essential as the transfer data, but other information is not essential.
This level information is not limited to the bit number I of the pixel effective bit I, but the line information D2 (pixel effective bit N) generated by the image signal processing unit 51 is level-converted by the level information conversion unit 81b. The number of pixel effective bits (= N−I) that is reduced when generating compressed line data (pixel effective bit I) may be used. Further, for example, the total number of line data is not always essential. On the restoration side, the restoration of the transfer data may be terminated when the line data to be restored are exhausted (not sent), or may be restored every time the line data is transmitted. Is.

Next, various embodiments of the operation of the reading control section 52 shown in FIG. 3 will be described with reference to FIGS. 7 to 9. 7 and 8 are flowcharts for explaining the operation of the reading control unit 52 corresponding to the case where the scanner unit 60 of the image reading apparatus 2 reads an image from a document sheet whose size is designated in advance. Further, FIG. 9 shows an operation of the irregular scanner unit 60 such as a case where the user turns on / off the operation switch of the scanner unit 60 of the handy type scanner to perform an operation of reading an image from a part of the original paper. 7 is a flowchart illustrating the operation of the corresponding read control unit 52.

First, the flow chart of FIG. 7 will be described. The process of this flowchart is a flowchart for explaining the operation of the read control unit 52 that generates the transfer data 70 in the format of FIG. In this process, two registers of setting LINE and reading LINE are used (these registers are also used in the flowchart of FIG. 8). The setting LINE is a register in which the number of read lines n obtained from the size of the document sheet read by the scanner unit 60, the line resolution of the image reading unit 61, and the like is set. The read line is a register in which the actual number of lines read by the scanner unit 60 is set.

First, "n" is set in the setting LINE (SA1). Next, the header information 71 of the transfer data 70 is created and output to the I / F unit 53 (SA2). Then, it is checked whether the set LINE value and the read LINE value are equal, and it is determined whether the processing has been completed for all the lines of the image read by the scanner unit 60 (SA3). Both LINE
If the values set in are not equal, it is determined whether an encoder pulse (pulse of the movement amount detection pulse signal S1) is input from the movement amount detection unit 62 (SA4). If no encoder pulse is input, the process returns to step SA3.

On the other hand, if the encoder pulse is input in step SA4, the line data D2 stored in the line buffer 57 of the level-converted image data generation unit 52a.
Are generated by the number of encoder pulses detected in step SA4 (SA5). For handheld scanners,
During the driving cycle of the image reading unit 61, the user scans the scanner unit 6
Since 0 may be moved by two lines or more, in such a case, in order to prevent loss of line data, the line data D2 read at the beginning of the driving cycle is copied by the number of encoder pulses. It should be noted that one line data D2 and the number of encoder pulses (movement amount data M) are used as in the case of the conventional invention 2 without copying a plurality of line data.
May be generated (see transfer data D3-2 in FIG. 15C).

Next, the value of read LINE is set in step SA4.
Incremented by the number of encoder pulses detected in (SA6), and based on the evaluation result of the transfer rate evaluation unit 52d, I
It is determined whether or not the transfer rate (data transfer rate) of the / F unit 53 is lower (slower) than the data generation rate S (SA7).
If the transfer speed of the I / F unit 53 is lower than the data generation speed S, the level conversion image data generation unit 52
a and the packing data generation unit 52b, step S
Level reduction (level conversion) processing and packing processing (packing conversion) are sequentially performed on the line data generated in A5 to compress the line data, and transfer line data is obtained based on the compressed line data obtained by the compression. Is generated and is output to the I / F unit 53 (SA9). Then, thereafter, the process returns to step SA3.

On the other hand, if the transfer rate of the I / F section 53 is equal to or higher than the data generation rate S in step SA7, then
Based on the evaluation result of the movement amount evaluation unit 52e, it is determined whether the moving speed of the image reading unit 61 of the scanner unit 60 is higher (faster) than the driving speed of the image reading unit 61 (SA8). And
When the moving speed of the image reading unit 61 is higher than the driving speed of the image reading unit 61, the process proceeds to step SA9, and the level conversion (level reduction) processing is performed by the level conversion image data generation unit 52a and the packing data generation unit 52b in step SA9. And packing processing (packing conversion) is performed to generate compressed line data, transfer line data is generated based on the compressed line data, and the transfer line data is output to the I / F unit 53 (SA
9) and returns to step SA3.

Further, in step SA8, when the movement amount evaluation unit 52e determines that the movement speed of the image reading unit 61 is equal to or lower than the driving speed of the image reading unit 61, the line data generated by the image signal processing unit 51 is used as the basis. To generate transfer line data and output it to the I / F unit 52 (SA
10) and returns to step SA3.

Then, in step SA3, read LINE
The processing of steps SA3 to SA10 is repeated until it is determined that the value of the same and the value of the set LINE are the same, and when it is determined in step SA3 that the value of the read LINE and the value of the set LINE are the same, the processing ends.

As described above, the reading control unit 52 generates the amount of line data to be transferred to the information processing device 65 (data generation speed S) according to the evaluation result of the transfer speed evaluation unit 52d or the movement amount evaluation unit 52e. Only when it is determined that the value exceeds the data transfer capability (data transfer rate) of the I / F unit 53, the line data is subjected to level conversion and packing conversion to compress the line data. Therefore,
The line data D2 generated by the image signal processing unit 51 is
Compressed only when needed. Therefore, the transfer data 70
The line data 72 may include both compressed data and uncompressed data (the line data D2 generated by the image signal processing unit 51).

Next, FIG. 8 is a flow chart for explaining the operation of the read control section 52 for generating the transfer data 75 in the format of FIG. In FIG. 8, steps that are the same as steps in FIG. 7 are given the same step symbols, and description of those steps is omitted. The flowchart of FIG. 8 is different from the flowchart of FIG. 7 in that, in step SA3, after it is determined that the read LINE value and the set LINE value are the same, the END code is output to the I / F unit 82 (SA11). The point is to end the processing.

Next, the operation of the reading control section 52 when the user reads an image from a part of the original sheet with the handy type scanner will be described with reference to the flowchart of FIG. This flowchart shows the start of operation of the image reading unit 61 provided in the scanner unit 60 of the image reading unit 61.
An operation switch (not shown) for instructing the end is set to ON, and the operation of the reading control unit 52 from the time when the reading of the image by the scanner is started is shown.

First, initialization is performed by setting "0" in the read LINE (SA21). This is because when the user reads an image such as a part of the original sheet with a handy type scanner, the number of read lines of the image is not known unless the user actually operates the scanner.

Next, the header information of the transfer data is created,
It is output to the I / F unit 82 (SA22). In this process, mainly the header information in which only the packing information is set is created.

Subsequently, it is determined whether the operation switch for instructing the start / end of the operation of the image reading section 61 provided in the scanner section 60 is OFF (SA23). If the operation switch is not OFF, it is determined whether the movement amount detection pulse signal S1 (encoder pulse) is input (SA
24), if there is no encoder pulse input, step S
Return to A23.

On the other hand, if there is an encoder pulse input,
Line buffer 5 of level conversion image data generation unit 52a
The line data D2 stored in 7 is generated by the number of encoder pulses (SA25). And read LINE
Is incremented by the number of encoder pulses (SA26). Further, in this step SA28,
In the line information 71c of the header information 71 of the transfer data 70, the value of read LINE set in step SA25 is set as the number of restored lines. The number of restored lines can be set by pressing the operation switch of the scanner in
It may be performed after it is determined that F is set.

Next, based on the evaluation result of the transfer speed evaluation unit 52d, it is determined whether the transfer speed of the I / F unit 53 is slower than the data generation speed S (SA29). Then, the I / F unit 53
If the transfer speed is lower (lower) than the data generation speed S, the level conversion (level conversion) is performed on the line data generated in step SA25 by the level conversion image data generation unit 52a and the packing data generation unit 52b.
And packing processing (packing conversion) is performed to create transfer line data, which is output to the I / F unit 53 (S
A29), and returns to step SA23.

If the transfer speed of the I / F unit 53 is equal to or higher than the data generation speed S in step SA27, then the moving speed of the image reading unit 61 of the scanner unit 60 is faster than the driving speed of the image reading unit 61 ( Determine if it is large (SA
28). If the moving speed is faster than the drive speed, level reduction and packing processing is performed on the line data generated in step SA25 in step SA29, and compressed line data is generated by these series of processing, and Generate transfer line data based on
It is output to the I / F unit 82 (SA29), and step S
Return to A23.

On the other hand, in step SA28, the moving speed of the image reading unit 61 of the scanner unit 60 is changed to the image reading unit 61.
If it is equal to or lower than the driving speed of, the transfer data is generated based on the line data D2 generated by the image signal processing unit 51, is output to the I / F unit 53, and the process returns to step SA23.

In steps SA23 to SA30, the operation switch of the scanner is turned off in step SA23.
It is repeated until it is determined that the result becomes F, and step SA
When it is determined in 23 that the operation switch of the scanner is turned off, the processing ends.

FIG. 10 is a block diagram showing a system configuration of a main part according to the present invention of the information processing apparatus 65 having a data decompression device for decompressing the compressed data received from the image reading device 1 of FIG.

The information processing device 65 comprises a data restoration unit 81 and an I / F unit 82. The I / F unit 82 is an interface that receives the compressed data transmitted from the I / F unit 30 of the image reading apparatus 1. The I / F unit 82 outputs the received compressed data to the data decompression unit 81 in units of lines, for example.

The data restoration unit 81 includes an unpacking processing unit 81a and a level information conversion unit 81b. The unpacking processing unit 81a performs an unpacking process on the compressed data (compressed line data) input from the I / F unit 82, and before the packing data generation unit 12 of the image reading apparatus 1 performs the packing conversion. Pixel effective bit I
Of the line data (intermediate line data) DM (see FIG. 1B) is output to the level information conversion unit 81b. The number of bits of the pixel effective bit N of each pixel of the intermediate line data DM is N bits like the input line data DI read by the sensor unit 40 of the image reading apparatus 1 (see FIG. 1A).

The level information conversion unit 81b performs level conversion on the line data DM input from the unpacking processing unit 81a, and outputs the pixel effective bit M (1≤M≤N) required by the information processing device 65. Line data is generated (restored) (see FIGS. 2F and 2I).

The unpacking processing unit 81a and the level information conversion unit 81b restore the compressed data received by the I / F unit 82 on a line-by-line basis, and finally restore all line data. The image data composed of the line data restored by the unpacking processing unit 81a and the level information conversion unit 81b is stored in the image data storage unit 90. The image data storage unit 90 is a magnetic disk, a magneto-optical disk, a semiconductor memory, or the like.

FIG. 10 is a flow chart for explaining the operation of the data restoration section 81 of FIG. Data restoration unit 81
Inputs the compressed data (compressed line data) received by the I / F unit 82 from the I / F unit 82 and stores it in an internal line buffer (not shown). The line buffer temporarily holds the compressed line data received by the I / F unit 82.

The unpacking processing unit 81a extracts compressed line data (line image data) from the line buffer.
Is read (SB1). In step SB1, it is also determined whether the reading of the compressed line data is completed. When there is no compressed line data to be read in the line buffer, it is determined that the reading of the compressed line data has been completed.

When the compressed line data is read in step SB1, the unpacking processing unit 81a performs unpacking processing on the compressed line data to generate intermediate line data DM (SB2). Next, the level information conversion unit 81b performs level conversion on the intermediate line data DM to restore / output the output line data (SB
3) and returns to step SB1.

The processing of steps SB1 to SB3 is repeated until it is determined in step SB1 that the reading of the compressed line data is completed, and finally the input line data DI read by the sensor section 40 of the image reading apparatus 1 is read. The output image data composed of the same number of line data as is restored. The number of pixels of each line data of the restored output image data is the same as the number of pixels of each line data of the input image data read by the sensor unit 40. In other words, the input image data and the output image data have the same spatial resolution information, and the data decompression unit 81 decompresses the image data compressed by the image reading device 1 while retaining the spatial resolution information.

The data compression section 10 and the read control section 5 described above.
2 and the respective functions of the data restoration unit 81 are equivalent to those of the computer (C
It can be realized by executing a program (PU or the like). That is, the level conversion image data generation units 11 and 52a, the packing data generation units 12 and 52b,
This can be realized by causing the computer to execute a program that causes the computer to execute the functions of the data speed detection unit 52c, the transfer speed evaluation unit 52d, the movement amount evaluation unit 52e, the unpacking processing unit 81a, and the level information conversion unit 81b.

A computer-readable recording medium (for example, CD-ROM, CD-
R, CD-RW, DVD, DVD-R, DVD-RW,
By storing the program on a flexible disk, a memory card or the like), it is possible to easily store or distribute the above program. Further, the program may be stored in an information processing apparatus such as a server connected to a network such as the Internet or a wide area LAN, and the program may be acquired from a device such as a personal computer connectable to the network via the network. Various distribution forms are also possible.

(Supplementary Note 1) A data compression device for compressing line data read by an image reading means for reading an image of an original on a line-by-line basis, wherein the digitized line data is input and each of the line data is input. First image data generating means for generating intermediate line data in which effective bits of pixels are reduced in the level direction, and bits other than effective bits are deleted from each pixel of the intermediate line data,
And a second image data generating unit that generates output line data in which pixels each including only valid bits are packed.

(Supplementary Note 2) The output line data includes
The data compression device according to appendix 1, wherein level information indicating the number of effective bits of each pixel is added. (Supplementary Note 3) A data transfer rate detecting means for detecting a data transfer rate of an interface for transferring the output image data, a data generating rate indicating an amount of data read by the image reading means per unit time, and the data. When the data transfer rate detected by the transfer rate detecting means is compared and it is evaluated that the data transfer rate is slower than the data amount sending rate, the effective bit number is set to the first image data generating means. The first image data generation means and the second image data generation means are evaluated by the transfer speed evaluation means as the data transfer speed being slower than the data generation speed. The data of Appendix 1, wherein the intermediate line data and the output line data are respectively generated only when Compressor.

(Supplementary Note 4) When the data transfer speed is evaluated by the transfer speed evaluation means to be equal to or higher than the data amount transfer speed, the digitized line data is output as it is. Note 3
The data compression device described.

(Supplementary Note 5) The output line data includes
6. The data compression device according to attachment 3 or attachment 4, wherein level information indicating the number of effective bits of each pixel is added.

(Supplementary Note 6) A signal indicating the moving amount of the image reading means is input, the moving speed of the image reading device is detected from the signal, and the moving speed is compared with the driving speed of the image reading means. A moving speed evaluating means for notifying the first image data generating means and the second image data generating means of the effective bit number when it is evaluated that the moving speed is faster than the driving speed, The first image data generation means and the second image data generation means respectively respectively include the intermediate line data only when the movement speed evaluation means evaluates that the movement speed is faster than the drive speed. And the output line data is generated.

(Supplementary Note 7) By the movement amount evaluation means,
7. The data compression apparatus according to appendix 6, wherein the digitized line data is output as it is when the moving speed is evaluated to be equal to or lower than the driving speed.

(Supplementary Note 8) The output line data includes
8. The data compression device according to appendix 6 or 7, wherein level information indicating the number of effective bits of each pixel is added.

(Supplementary Note 9) A data compression method for compressing line data read by an image reading means for reading an image of an original on a line-by-line basis, wherein the digitized line data is input and each of the line data is input. A step of generating intermediate line data in which effective bits of pixels are reduced in the level direction, and an output line in which pixels other than the effective bits are deleted from each pixel of the intermediate image data and pixels having only effective bits are packed A data compression method comprising an output line data generation step of generating data.

(Supplementary note 10) The data compression method according to supplementary note 9, wherein level information indicating the number of effective bits of each pixel is added to the output line data. (Supplementary Note 11) A data transfer speed detecting step of detecting a data transfer speed of an interface for transferring the output image data, a data generating speed indicating a generation amount of data read by the image reading unit per unit time,
When the data transfer rate detected by the data transfer rate detection step is compared and the data transfer rate is evaluated to be slower than the data amount transfer rate, the valid data used in the intermediate line data generation step is detected. A data transfer rate evaluation step for obtaining the number of bits, wherein the intermediate line data generation step and the output line data generation step are:
10. The data compression method according to note 9, which is executed only when it is evaluated that the data transfer rate is slower than the data generation rate.

(Supplementary Note 12) In the transfer speed evaluation step, if the data transfer speed is evaluated to be equal to or higher than the data amount transfer speed, the digitized line data is output as it is. 12. The data compression method according to feature 11, which is a feature.

(Supplementary note 13) The data compression method according to Supplementary note 11 or Supplementary note 12, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 14) A signal indicating the amount of movement of the image reading means is input, the moving speed of the image reading device is detected from the signal, and the moving speed is compared with the driving speed of the image reading means. When the moving speed is evaluated to be faster than the driving speed, a moving speed evaluating step for obtaining the effective bit number used in the intermediate line data generating step and the output line data generating step is provided, 12. The data according to appendix 11, wherein the line data generating step and the output line data generating step are executed only when the moving speed is evaluated to be faster than the driving speed in the moving speed evaluating step. Compression method.

(Supplementary Note 15) In the movement amount evaluation step, if the movement speed is evaluated to be equal to or lower than the drive speed, the digitized line data is output as it is. 14. The data compression method according to 14.

(Supplementary Note 16) The data compression method according to Supplementary Note 14 or 15, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 17) A computer-readable recording medium in which a program for causing a computer to execute a process of compressing line data read by an image reading means for reading an image of an original in line units is recorded and digitized. The step of inputting the processed line data, and generating intermediate line data in which effective bits of each pixel of the line data are reduced in the level direction, and deleting bits other than the effective bit from each pixel of the intermediate line data. And a computer-readable recording medium recording a program for causing the computer to perform an output line data generation step of generating output line data in which pixels each including only valid bits are packed.

(Supplementary Note 18) The computer-readable recording medium according to Supplementary Note 17, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 19) The program further causes the computer to detect the data transfer rate of an interface for transferring the output image data, and to store data read by the image reading unit per unit time. When the data generation rate indicating the generation amount is compared with the data transfer rate detected by the data transfer rate detecting means, and it is evaluated that the data transfer rate is slower than the data amount transfer rate, the intermediate line While executing the processing of the data transfer rate evaluation step for obtaining the number of effective bits used in the data generation step,
The process of the intermediate line data generation step and the process of the output line data generation step are executed only when the data transfer rate is evaluated to be slower than the data generation rate in the process of the data transfer rate evaluation step. A computer-readable recording medium according to supplementary note 17, characterized in that the program is evaluated in the transfer rate evaluation step as the data transfer rate being equal to or higher than the data amount transfer rate. Note 18 in which the computer is caused to execute a process of directly outputting the digitized line data.
The computer-readable recording medium described in the above.

(Supplementary Note 21) The computer-readable recording medium according to Supplementary Note 19 or Supplementary Note 20, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 22) The program further inputs a signal indicating the amount of movement of the image reading means to the computer, detects the moving speed of the image reading device from the signal, and detects the moving speed and the moving speed. When the driving speed of the image reading means is compared and it is evaluated that the moving speed is faster than the driving speed, the processing of the moving speed evaluating step for obtaining the effective bit number used in the intermediate line data generating step. And the process of the intermediate line data generating step and the process of the output line data generating step are performed only when the moving speed is evaluated to be faster than the driving speed in the processing of the moving speed evaluating step. Appendix 17 characterized by being executed
The computer-readable recording medium described in the above.

(Supplementary Note 23) The program performs a process of outputting the digitized line data as it is when the moving speed is evaluated to be equal to or lower than the driving speed in the moving amount evaluating step. 23. The computer-readable recording medium according to appendix 22, which is executed by the computer.

(Supplementary Note 24) The computer-readable recording medium according to Supplementary Note 22 or 23, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 25) A program for causing a computer to execute a process of compressing line data read by an image reading means for reading an image of an original in line units, and inputting the digitized line data, Generating intermediate line data in which effective bits of each pixel of the line data are reduced in the level direction,
A program for causing the computer to execute a process including an output line data generation step of deleting output bits other than valid bits from each pixel of the intermediate line data to generate output line data packed with pixels including only valid bits. .

(Supplementary note 26) The program according to supplementary note 25, wherein level information indicating the number of effective bits of each pixel is added to the output line data. (Supplementary Note 27) The program further causes the computer to perform a process of a step of detecting a data transfer rate of an interface for transferring the output image data, and an amount of data generated by the image reading unit per unit time. The intermediate line data generation step, in which the data generation rate shown is compared with the data transfer rate detected by the data transfer rate detecting means, and when the data transfer rate is evaluated to be slower than the data amount transfer rate And executing the processing of the data transfer rate evaluation step of obtaining the number of effective bits used in the output line data generation step, the processing of the intermediate line data generation step and the processing of the output line data generation step In the processing of the transfer rate evaluation step, the data transfer rate 26. The program according to claim 25, which is executed only when the degree is evaluated to be slower than the data generation rate.

(Supplementary Note 28) If the data transfer speed is evaluated to be equal to or higher than the data amount transfer speed in the transfer speed evaluation step,
28. The program according to appendix 27, which causes the computer to execute a process of directly outputting the digitized line data.

(Supplementary Note 29) The program according to Supplementary Note 27 or Supplementary Note 28, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 30) The program further inputs a signal indicating the movement amount of the image reading means to the computer, detects the movement speed of the image reading device from the signal, and detects the movement speed and the When the driving speed of the image reading means is compared and it is evaluated that the moving speed is faster than the driving speed, the processing of the moving speed evaluating step for obtaining the effective bit number used in the intermediate line data generating step. And the process of the intermediate line data generating step and the process of the output line data generating step are performed only when the moving speed is evaluated to be faster than the driving speed in the moving speed evaluating step. Appendix 25 characterized by being executed
The listed program.

(Supplementary Note 31) The program performs a process of directly outputting the digitized line data when the moving speed is evaluated to be equal to or lower than the driving speed in the moving amount evaluating step. 31. The program according to appendix 30, which is executed by the computer.

(Supplementary Note 32) The program according to Supplementary Note 30 or 31, wherein level information indicating the number of effective bits of each pixel is added to the output line data.

(Supplementary Note 33) For input line data, level conversion is performed to reduce bits of the pixel of the input line data in the level direction, and the pixel is selected according to the number of bits of the pixel reduced by the level conversion. What is claimed is: 1. A data decompression device for decompressing compressed line data generated by performing a packing conversion for packing, wherein unpacking conversion for returning the pixel of the compressed line data to the pixel before the level conversion for the compressed line data. And a restoring means for restoring the line data before the level conversion,
And a generation unit that converts the level of a pixel of the line data generated by the restoration unit to generate line data composed of pixels of a predetermined bit.

(Supplementary Note 34) The supplementary means performs the unpacking conversion based on level information indicating the number of bits reduced by the level conversion added to the compressed line data. The described data restoration device.

(Supplementary Note 35) For input line data, level conversion is performed to reduce the bits of the pixel of the input line data in the level direction, and the pixel is selected according to the number of bits of the pixel reduced by the level conversion. A data decompression method for decompressing compressed line data generated by performing packing conversion for packing, which is an unpacking conversion for returning the pixel of the compressed line data to the pixel before the level conversion with respect to the compressed line data. And a restoration step of restoring the line data before the level conversion, and a generation step of converting line levels of pixels of the line data generated by the restoration step to generate line data composed of pixels of predetermined bits, A data restoration method comprising:

(Supplementary Note 36) In the decompression step, the unpacking conversion is performed based on the level information indicating the number of bits reduced by the level conversion added to the compressed line data. Data recovery method described.

(Supplementary Note 37) For input line data, level conversion is performed to reduce the bits of the pixel of the input line data in the level direction, and the pixel is selected according to the number of bits of the pixel reduced by the level conversion. What is claimed is: 1. A computer-readable recording medium having recorded therein a program for executing a process of restoring compressed line data generated by carrying out packing conversion for packing, to the compressed line data. Performing the unpacking conversion to restore the pixels of the line data before the level conversion to restore the line data before the level conversion, and the level of the pixel of the line data generated by the restoring means is converted to a predetermined bit. The computer including the step of generating line data composed of A computer-readable recording medium recording a program to be executed by a computer.

(Supplementary Note 38) The program executes the unpacking conversion on the computer based on the level information indicating the number of bits reduced by the level conversion added to the compressed line data in the decompression step. 38. The computer-readable recording medium according to Supplement 37.

(Supplementary note 39) For input line data, level conversion is performed to reduce the bits of the pixel of the input line data in the level direction, and the pixel is selected according to the number of bits of the pixel reduced by the level conversion. A program for causing a computer to execute a process of restoring compressed line data generated by performing packing conversion for packing, wherein the pixel of the compressed line data is converted into the pixel before the level conversion with respect to the compressed line data. An unpacking conversion for returning is performed to restore the line data before the level conversion, and the level of the pixel of the line data generated by the restoring step is converted to generate line data composed of pixels of predetermined bits. A program that causes the computer to execute a process including a generating step.

(Additional remark 40) In the decompression step, the program executes the unpacking conversion on the computer based on the level information indicating the number of bits reduced by the level conversion added to the compressed line data. 40. The program according to note 39, wherein

[0154]

As described above, the data compression apparatus of the present invention, the program for causing a computer to realize the function of the data compression apparatus, and the data decompression apparatus for decompressing the compressed data generated by the data compression apparatus, It has the following effects or advantages.

(1) In the data compression according to the present invention, it is suitable for the compression of line data in which it is important that the spatial resolution information is preserved at the time of decompression. Therefore,
For example, when applied to the compression of a two-dimensional code, the decoding rate of the two-dimensional code on the decompression side can be improved.

(2) In the data compression according to the present invention, the data (line data) read by the image reading unit.
Generation rate (data generation rate) and the transfer rate of the interface that transfers the data to the decompression side are constantly compared, and only when it is determined that compression is necessary, the data is compressed and output to the interface. Therefore, for example, it is suitable for compression of data read by an image reading apparatus having a high data generation speed such as a scanner having a high-resolution line sensor or a scanner having a high-speed line sensor. is there. In addition, in the data compression according to the present invention, the line data read by the image reading unit is
Compress and transfer only when it is determined that compression is necessary,
When it is determined that the compression is not necessary, the data is transferred as it is. Therefore, the data restoration according to the present invention can more accurately restore the data (line data) read by the image reading unit while preserving the spatial resolution information. You can

(3) In the data compression according to the present invention, both the driving speed and the moving speed of the image reading unit are always set to
By comparison, the line data read by the image reading unit is compressed and output by the above method only when it is determined that the image reading unit needs to be compressed. The line data is compressed only when such a user operation is performed, and the line data is output without being compressed during the other user operations. Therefore, the moving speed of the image reading unit is changed according to the user operation. It is suitable for handheld scanners that fluctuate. For example, by incorporating the data compression device or the program of the present invention in the handy-type scanner, it is possible to prevent the line data reading omission by the handy-type scanner. Also,
Also in this data compression, the line data read by the image reading unit is compressed and transferred only when it is determined that the compression is necessary, and is transferred as it is when the compression is determined to be unnecessary. By the data restoration, the data (line data) read by the image reading unit can be restored more accurately while preserving the spatial resolution information.

(4) In the data decompression according to the present invention, the compressed line data in which the spatial resolution information generated by the data compression according to the present invention described in (1) to (3) is stored is In the compression process, the state before the level conversion is restored, and further, regarding the restored line data, the level information (effective bit number) of the pixel is used, the application, the processing device, the output device, etc. Since it is converted into level information suitable for and output, it is excellent in applicability.

[Brief description of drawings]

1A to 1D are diagrams illustrating the principle of a data compression / decompression method according to an embodiment of the present invention.

2A to 2I are diagrams for explaining in more detail the principle of the data compression / decompression method according to the embodiment of the present invention, focusing on pixels.

FIG. 3 is a block diagram showing a system configuration of an image reading apparatus including the first embodiment of the data compression apparatus of the present invention.

FIG. 4 is a block diagram showing a system configuration of an image reading apparatus including a second embodiment of a data compression apparatus of the present invention.

5 is a diagram showing a first form of a format of transfer data transmitted from the image reading apparatus of FIGS. 3 and 4. FIG.

FIG. 6 is a diagram showing a second form of a format of transfer data transmitted from the image reading apparatus of FIGS. 3 and 4;

FIG. 7 is a flowchart illustrating a first embodiment of the operation of the image reading apparatus in FIG.

FIG. 8 is a flowchart illustrating a second embodiment of the operation of the image reading apparatus in FIG.

9 is a flowchart illustrating a third embodiment of the operation of the image reading apparatus in FIG.

FIG. 10 is a block diagram showing a system configuration of a main part of an information processing device including a data restoration device of the present invention.

11 is a flowchart illustrating an operation of the data restoration device of FIG.

FIG. 12 is an external view showing an example of a hardware configuration of a handy type scanner.

FIG. 13 is a block diagram showing a system configuration of a conventional image reading system.

14 (a) to (i) are time charts showing the operation of the conventional image reading system.

15A to 15C are diagrams illustrating a transfer / restoring operation of data generated in a normal transfer mode of the conventional image reading system.

16 (a) to 16 (d) are diagrams illustrating transfer / compression of compressed data generated in the compression transfer mode of the conventional image reading system.
It is a figure explaining a restoration operation.

17A and 17B are diagrams showing a two-dimensional code and an image restored based on the two-dimensional code.

[Explanation of symbols]

1 and 2 image reading device 3,50 Data processing unit 10 Data compression unit 11 Level conversion image data generator 12 Packing data generator 20 Image signal processing unit 30, 53 I / F section (data transfer section) 40 sensor 52 Read control unit (data compression unit) 52a Level conversion image data generation unit 52b Packing data generator 52c Data rate detector 52d Transfer rate evaluation unit 52e Movement amount evaluation unit 57 line buffer 60 Scanner 61 Image reading unit 62 Movement amount detection unit 65 Information processing equipment 70,75 Transfer data 71,76 Header information 71a, 76a Level information 71b, 76b Packing information 71c Line information A 76c Line information B 72, 77 line data 78 END code 81 Data recovery unit 81a Unpacking processing unit 81b Level information conversion unit

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5C072 AA01 BA03 BA17 PA02 PA10                 5C078 AA04 BA21 CA01 CA31 CA34                       DA01 DB04 DB06                 5J064 AA00 BA00 BC00 BC14 BC29                       BD04

Claims (5)

[Claims] 1. A data compression apparatus for compressing line data read by an image reading means for reading an image of an original on a line-by-line basis, wherein the digitized line data is input to each pixel of the line data. First image data generating means for generating intermediate line data in which effective bits are reduced in the level direction, and bits other than the effective bits are deleted from each pixel of the intermediate line data so that pixels having only effective bits are packed. A second image data generating means for generating the generated output line data, and a data compression device. 2. A data transfer speed detecting means for detecting a data transfer speed of an interface for transferring the output image data, a data generating speed indicating a generation amount of data read by the image reading means per unit time, When the data transfer rate detected by the data transfer rate detecting means is compared and it is evaluated that the data transfer rate is slower than the data amount sending speed, the first image data generating means and the second image data generating means. The image data generating means is provided with a transfer rate evaluating means for notifying the effective bit number, and the first image data generating means and the second image data generating means are configured to determine the data transfer rate by the transfer rate evaluating means. Only when it is evaluated to be slower than the data generation speed, the intermediate line data and the output line data are generated, respectively. Claim 1, characterized in that
The data compression device described. 3. A signal indicating the amount of movement of the image reading means is input, the moving speed of the image reading device is detected from the signal, and the moving speed and the driving speed of the image reading means are compared, When it is evaluated that the moving speed is faster than the driving speed, a moving speed evaluating means for notifying the first image data generating means and the second image data generating means of the effective bit number is provided, The image data generating unit 1 and the second image data generating unit, only when the moving speed evaluation unit evaluates that the moving speed is faster than the driving speed,
The data compression apparatus according to claim 1, wherein the intermediate line data and the output line data are generated respectively. 4. A program for causing a computer to execute a process of compressing line data read by an image reading means for reading an image of an original on a line-by-line basis, wherein the digitized line data is input and the line data is input. A step of generating intermediate line data in which the effective bits of each pixel are reduced in the level direction, and bits other than the effective bits are deleted from each pixel of the intermediate line data so that pixels consisting of only the effective bits are packed. A program that causes the computer to execute a process including an output line data generation step of generating output line data. 5. The input line data is level-converted to reduce the bits of pixels of the input line data in the level direction, and the pixels are packed according to the number of bits of the pixel reduced by the level conversion. A data decompression device for decompressing compressed line data generated by performing packing conversion, wherein the compressed line data is subjected to unpacking conversion for returning the pixels of the compressed line data to the pixels before the level conversion. A restoring unit that restores the line data before the level conversion, and a generating unit that converts the level of a pixel of the line data generated by the restoring unit to generate line data including pixels of a predetermined bit. A data restoration device characterized by the above.