JPH01318354A - Image reader - Google Patents

Abstract

PURPOSE:To transfer digital data related to plural image transfer forms at a time by converting image information to be transferred to an external device to a set of data related to two or more image transfer forms and defining information corresponding to one picture element as a minimum transfer unit. CONSTITUTION:A binarizing circuit 25 modulates multivalued information to binary and dither information by slice data for conversion to binary information and dither slice data for conversion to dither information which are preliminarily set by a CPU 27. Binary and dither information outputted from the binarizing circuit 25 is converted to image information having eight bits as one picture element by an interface circuit 26. For example, multivalued information is set to bits 0-5, and dither information is set to bit 6, and binary information is set to bit 7. Image information to be transfered to the external device is converted to at least two or more image transfer forms and information of one picture element is defined as a minimum transfer unit in this manner, thereby simplifying a reader and reducing the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device that converts image information into multi-bit digital data and outputs the converted data.

[Prior Art] In a conventionally known image reading device, a document is first irradiated, and the irradiated image information is photoelectrically converted into, for example, a digital value of 4 bits per pixel. 2. Multi-value information (hereinafter referred to as multi-value) in which 1 pixel is represented by 4 bits; 2. In which a predetermined digital value is used as a slice level and 1 pixel is represented by 1° and 0° information. Value information (hereinafter referred to as binary), ■Binarized dither information (hereinafter referred to as dither) in which each digital value of the mxn matrix is used as a slice level, and one pixel is expressed as 1° and 0° information. ).

Next, the modulated image information is transferred in a transfer format in which one pixel is 8 bits or two pixels are 8 bits in the case of multilevel information, and 8 pixels are in 8 bits in the case of binary and dither information. The data is transferred to an external device using the transfer format.

Therefore, the image reading device reads the original and performs image modulation based on a preset transfer format (multi-value 1 pixel 8 bits, multi-value 2 pixels 8 bits, binary/dither 8 pixels 8 bits). .

(Problem to be solved by the invention) As mentioned above, in the conventional example, one pixel is 8 bits or 2 bits.
As can be seen in the 8-bit pixel multivalue information, the 8-pixel 8-bit binary information, and the dither information, there are 3 types of transfer formats and 3 types of information formats when transferring image information to an external device. For this reason, before transferring the image to the external device, there is a circuit that converts 1 pixel into 8 bits, 2 pixels into 8 bits, and 8 pixels into 8 bits, and a circuit that selects one of the three transfer formats. or is necessary.

In particular, in a reading device that distinguishes and reads text and photographs in a document, a circuit is required to distinguish between text (binary information) and photographs (dither information). As a result, the hardware within the reader cannot be made smaller by having the necessary circuitry, and the means for specifying the transfer format and information format (in the case of commands from an external device, from the external device to the reader) If the reading device has a command means for image reading, a control coat for informing the external device of the transfer format is required.

SUMMARY OF THE INVENTION In view of the above-mentioned points, an object of the present invention is to provide an image reading device configured to transfer digital data in a plurality of image transfer formats at once.

[Means to solve the problem]

In order to achieve such an object, the present invention provides an image reading device that converts image information per pixel into one or more bits of digital data and outputs the same, in which digital data related to a plurality of image transfer formats is converted for each pixel. It is provided with a combining means for integrating data into data of a specific bit length, and outputs one pixel information as a minimum transfer unit.

[Function] In the present invention, image information to be transferred to an external device is a collection of data related to at least two or more types of image transfer formats,
The minimum transfer unit is one pixel worth of information.

[Embodiment] In an embodiment of the present invention, one pixel photoelectrically converted by a reading device is modulated into three fffi types of image information including multivalue, binary, and dither, and then the image is transferred directly to an external device. (In the case of multilevel information, 8 bits per pixel or 8 bits for 2 pixels; in the case of binary/dither information, 8 bits per 8 pixels)
The multi-value, binary and dither image information is combined and transferred to an external device as multi-value, binary and dither image information of 8 bits per pixel.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing the internal configuration of a document reading device to which the present invention is applied.

Reference numeral 1 is a main body of the original image reading apparatus, and the original on the platen glass 17 is illuminated by the original illumination unit 15, and the original image is formed on the CCD 12 by the lens 14.

FIG. 2 shows the CCD driver 13 and control unit 11.
FIG. 2 is a block diagram showing the circuit configuration of FIG.

The operation of the document reading device will be explained using FIGS. 1 and 2.

The reading device according to the wooden embodiment is always connected to an external device (such as a personal computer), and communication of control signals with the external device and output of image information signals to the external device are performed via the interface circuit 26.

With the document 18 placed on the platen glass 17, various mote instructions are inputted from an external device. For example, which pixel density to set, which image magnification to set, etc.

When the CPU 27 receives this, the timing signal generation circuit 28 and motor drive signal output section (not shown)
, and set the pixel density and image magnification mentioned above.

Next, when receiving an instruction to start reading from an external device, the CP
After confirming that the optical system is at the initial reading position by the optical position sensor signal, U127 outputs a lamp control signal to turn on the lamp, and after the light intensity of the lamp becomes stable, it outputs a motor 1 live signal. Move the optical system to the reading start position.

During this time, the image formed on the CCD 12 is either converted into a digital value and inputted to the interface circuit 26, or since this is not the original image, the CPt 127 gives a control signal to the interface circuit 2δ so as not to output an image signal.

When the optical system power monopolization start position is reached, the CPU 27 outputs a control signal to enable image signal output to the interface circuit 26, and the read image information is sent one after another to an external device. When the document reading end position is reached, a control signal disabling image output is given to the interface circuit 26, and a document reading end signal is output to the external device.

CPt127 outputs a lamp control signal to turn off the lamp. CPLI27 outputs a motor drive signal to move the optical system to the initial signal, and after confirming from the optical position sensor signal that the optical system has reached the initial signal, stops outputting the motor drive signal and starts the reading operation. end.

Then, it is irradiated by a lamp, passes through the lens 14, and the C
The process by which the image formed on the CD 12 is output to an external device will be explained.

CGDI2 on the CCU driver 13 is the control unit 1
The CCD drive circuit 23 is driven by a timing signal generated by a timing signal generation circuit 28 on the CCD drive circuit 23 . The image analog signal output from the CGDI 2 is amplified by the amplifier 21 and then input to the D/D converter z2. The converter 22 converts the image signal or analog signal into a 6-bit digital signal according to the timing signal generated by the timing signal generating circuit 28 (see FIG. 3), and outputs it to the control unit 11.

The control unit detects high-frequency distortion (
The shading correction circuit 24 corrects the non-uniformity of the lamp, the variation in each pixel characteristic of the GCD, and dust), and outputs it to the interface circuit 26 and the binarization circuit 25.

The binarization circuit 25 modulates the 6-bit multilevel information into binary/dither information using the slice data for binary information and the dither slice data for dither information set by the preliminary CPLI 27. (See Figure 4).

The main scanning dither matrix is written from the CPLI 27 to the 6-bit latch×8 latch circuits 41. This latched data is stored in 6-bit latches x 8 latch circuits 42.
is input to. This data is φ84. The dither matrix data latched in and currently written in the latch circuit 41 is manually inputted to the selector with counter 43 during the next sub-scan reading.

The selector with counter 43 repeatedly counts up from 0° to 7° using φAD (1 pixel clock) and selects 1 dither data of the 8 dither data output from the latch circuit 42. It has become.

Then, this selected data is manually input to the comparator 45,
The slice data is 6-bit multi-level information output from the A/D converter 22. Here, for each sub-scan, C
From PU27, 8 pieces of sub-scanning data (6 bits x
8) into the latch circuit 41, it is possible to realize 8×8 dither.

The binary/dither information output from the binarization circuit 25 is 1
The interface circuit 26 converts the image information into 8-bit pixel image information.

FIG. 5 shows the image data output section within the interface circuit 26. Here, combinations of three types of image information are shown when multilevel information is set to bit 0 to bit 5, dither information is set to bit 6, and binary information is set to bit 7.

In this way, the image data format output from the reading device is
The standard 1-pixel 8-bit combination method allows multi-level, dither,
It becomes possible to transfer binary information all at once to an external device.

〔Effect of the invention〕

As explained above, according to the present invention, the reading device can be simplified by using at least two types of image transfer formats for image information to be transferred to an external device and by setting the minimum transfer unit to one pixel information. , costs can be reduced.

The present invention is effective in, for example, a sheet-through scanner, and when changing the image mode (multilevel, dither, 24m) and reading, there is no need to insert the original into the reading device each time, and the reading operation can be performed in one step. Times are fine.

Further, according to the present invention, when reading a document containing a mixture of text and photographs, there is no need to specify areas for text and photographs to the reading device, and it is possible to set the area using an external device and to specify an irregularly shaped area. It is also possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the internal configuration of a document reading device to which the present invention is applied. FIG. 2 is a block diagram showing the configuration of the CCD driver and control unit in this embodiment. FIG. 3 is a diagram showing the operation of this embodiment. FIG. 4 is a detailed block configuration diagram of the binarization circuit in this embodiment, and FIG. 5 is a diagram showing the input/output mode of the interface circuit in this embodiment. DESCRIPTION OF SYMBOLS 1... Original reading device, 11... Control unit, 12... CCD. 13... COD driver, 14... Lens, 15... Original illumination unit, +8... Reflection mirror, 17... Platen glass, 18... Original, 19... Platen cover, 24. ...shading correction circuit, 25...binarization circuit, 26...interface circuit, 27...cpu 0

Claims (1)

[Scope of Claims] 1) In an image reading device that converts image information per pixel into one or more bits of digital data and outputs the converted image information, digital data related to multiple image transfer formats are integrated for each pixel. An image reading device characterized by comprising a combining means for converting data into data of a specific bit length, and outputting one pixel information as a minimum transfer unit. 2) The image reading device according to claim 1, wherein multivalued data, binary data, and dithered data having a predetermined bit length are used as the digital data related to the plurality of image transfer formats.