JPH0732459B2 - Encoder - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coding device used in a facsimile, an electronic file system, or the like.

2. Related Art Third example of using a conventional encoding device in a facsimile device
It will be described with reference to the drawings. As shown in FIG. 3, the image data read by the image scanner 51 is stored in the image memory 52, and the data is input to the encoding / decoding device 54 to be used as a facsimile encoding method. The MH, MR, etc. specified by Recommendation T.4 of the Society) are being processed. At this time, if the image memory has a large capacity, it is possible to store one page of image data. In this case, since the number of lines in the image memory 52 is already known, if this value is set in the encoding / decoding device 54 as the number of lines to be continuously processed, continuous processing of one page data is possible. Moreover, the processing load on the microprocessor (hereinafter MPU) is small. However, when attempting to perform encoding processing by real-time scanning, the number of lines in one page is unknown at the time of parameter setting, and because of cost reasons, the image memory 52 often has a memory of several lines. The input from the image scanner 51 and the encoding process are repeated in steps. In this case, every time several lines are processed, the MPU must set and start the number of processing lines to the encoding / decoding device 54 many times within one page, which increases the processing load of the MPU.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, in the conventional configuration, when the encoding process is performed while scanning in real time with the image scanner, the processing load of the MPU increases, and when the processing load of the MPU is reduced, the image There is a problem that the memory capacity increases and the cost of the entire system increases.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to enable a continuous encoding process without burdening the MPU while performing real-time scanning by making a simple improvement in the encoding device. Especially.

Means for Solving the Problems To achieve the above object, a reading unit that scans a target document to read image data, and an image data storage unit that temporarily stores several lines of the image data read by the reading unit, Encoding means for encoding the image data of several lines stored in the image data storage means, detecting means for detecting the end of the target document read by the reading means, and image data read by the reading means The image data storage means is temporarily stored in the image data storage means, and a predetermined number of lines to be continuously encoded is sequentially encoded by the encoding means, and when the detection means detects the end of the target document, the image data storage means. The number of unprocessed lines stored in is calculated and set again, and a control means for causing the encoding means to encode this number of lines is provided. It is a thing.

According to the present invention, the reading unit reads the target document, the preset number of lines is temporarily stored in the image data storage unit, and is encoded by the encoding unit, and the detection unit detects the end of the target document. Upon detection, the number of unprocessed lines remaining in the image data storage means is calculated and set again, and the encoding means encodes the number of lines.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The overall configuration of the device is the same as the configuration described in FIG. That is, at the time of encoding, the image data input by the scanner 51 is temporarily stored in the image memory 52, and then the encoding / decoding device 54
Input to and output as coded data. Further, at the time of decoding, the coding / decoding device 54 inputs the coded data and outputs it as decoded image data to the image memory 52, and outputs it from the image memory 52 to the printer 53 to restore the image. The MPU controls all of these operations.

FIG. 1 shows a schematic configuration of an encoding / decoding device 54 which is the center of the present invention. The coding / decoding device 54 temporarily holds the coded data, the coded reference data, and the restored image data. The upper stage is for the reference line, and the lower stage is for the image line input / output FIFO1, Change pixel detection / detection circuit composed of a change pixel detection circuit for coded data and coded reference data and a coding / decoding mode determination circuit
Mode determination unit 2, latch circuit 3 for temporarily holding the detection result of the encoding mode, code ROM 4 in which run length code or MR code is written, P / S conversion circuit 5 for converting output data of code ROM to serial data A shift register 6 for aligning serial data to a word size, a timing control circuit 7 for supplying the processing timings 4 to 6 above, and temporarily holding coded data aligned to a word size by the processing of the timing control circuit 7. Encoded data output FIFO8, timing control circuit 9 for controlling input / output timing to encoded data output FIFO8, encoded data input FIFO10 for temporarily holding data to be decoded, timing control for controlling data input / output to / from FIFO10 The output of the circuit 11, the output data of the FIFO11, the timing control circuit 13, the code ROM14 for restoration, and the output of the latch 12 are changed to the code ROM14 for retrieval. Conversion circuit 15, a latch circuit 16 for temporarily holding a decoded code, a control unit 17 including a sequencer and an arithmetic circuit for controlling the entire encoding / decoding device, and a control under the control of the control unit 17. Unit 18, image data input / output FIFO1 timing control circuit 19, image data interface unit 20 for controlling input / output of image data to the memory, multiplexer 21, MPU interface unit 22, register file 23 accessed by MPU, image Data bus 24, address bus 25,
From the access control signal 26 of the image memory, the control signal 27 for executing the DMA transfer, the coded reference data line 28, the coded data line 29, the input / output signals 30 and 31 of the mode determination unit 2 and the input / output signal of the control unit 17. Control bus 32, control signal lines 33, 34, data bus 35, address signal 36 for MPU to read / write register file 23, R / W, data request, IRQ request, etc. for MPU, MPU peripheral device Control signal 37,3
8, MPU data bus 39, register file 23 output line
40, status register 4 for displaying the internal status of control unit 17
1, a control register 42 for instructing an operation mode, an address register 43 for selecting a parameter storage register in the control unit 18, a status information 44 for informing the MPU of prohibition or permission of access to this parameter storage register , Control signal 4 requesting stop of encoding / decoding operation
It consists of 5.

FIG. 2 shows the internal structure of the control unit 18 shown in FIG. The configuration includes multiplexers 181, 182, registers 183, 184, 185, arithmetic logic operation unit (ALU) 186, shifter 187, accumulator 188 for holding the operation result of ALU 186, comparator 190, output signal 191, of comparator 190, register file 192, stack pointer. 193,
Stack file 194, program counter 195, input signal
Mapping that determines the processing address according to the contents of 33
ROM196, multiplexer 197, microprogram ROM198,
Pipeline register 199 that latches the output of ROM 198, multiplexer 200, address control circuit 201 that determines the next processing address, multiplexer 202 that switches the address 205 when the sequencer accesses register 192, and output 46 of address register 43, multiplexer 202 The input is switched by the signal 203 and the address 204 of the register 192.

Next, the operation will be described with reference to FIG. Fig. 4 shows MPU
It shows an example of the flow of the side. In step 100, parameters necessary for encoding and decoding are written in the register 192. These parameters are, for example, the number of pixels in one line, the number of continuous processing lines, and the like. Register setting is MPU
Writes the data to be set in the data register 23. Further, the address of the parameter storage register 192 is written in the address register 43. The sequencer outputs the address signal 240 by the signal 203 and the address 46 of the address register 43.
Is output. On the other hand, the output 40 of the data register 23 is output to the internal data bus 35 through the multiplexer 21. Parameters are set in the register 192 by the control signal 206 such as the above address and data R / W. At this time, a large value is set as the number of processing lines. For example, in A4 size, the number of lines per page is around 2400 lines.
Set a value of around 2500 lines. M in step 101
The PU activates the encoding / decoding device 54 to start the encoding process.

In step 102, it is determined whether or not the image scanner 51 has scanned the page edge of the document as the processing target image data position. This is generally done by monitoring the MPU for sensor output to detect the page edge. Up to the page edge, data input processing from the image scanner 51 to the image memory 52 and the main encoding / decoding device
Encoding processing by 54 is being performed. MPU step 102
When the page edge is detected at, the control register 42 is set and the signal 45 requesting a temporary stop of operation is turned on. The signal 45 is an input signal to the sequencer through the control buses 33 and 34 of the sequencer. When the sequencer detects that the signal 45 is ON, it switches the input signal of the multiplexer 202 to the 46 side at an appropriate timing. This switching is done with control signal 20
Do by 3. After that, to notify the MPU of access to the parameter storage register 192, set its status bit to O.
The signal 44 is turned on to turn off the signal. When the MPU confirms that the signal 44 has been turned ON in step 104, it stores the number of unprocessed lines in the image memory 52 in the register 192 in step 105.
Set again to. In step 106, the temporary stop request signal that was turned on in step 103 is turned off and the encoding process is restarted. In step 106, the encoding process for the number of lines set in step 105 is performed, and the encoding of the entire page is completed.

According to the present invention, the number of lines to be continuously encoded is set in advance, and when the detection unit detects the end of the target document, the number of unprocessed lines remaining in the image data storage unit is calculated,
By setting again, there is an effect that continuous processing in real time can be realized without imposing a heavy load on the control means.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of an encoding / decoding device which is the center of the device according to an embodiment of the present invention, and FIG. 2 is a control unit 18 of FIG.
Is a schematic configuration diagram of FIG. 3, FIG. 3 is a diagram showing a configuration example of a device including an encoding / decoding device, and FIG. 4 is a flow diagram of the present embodiment. 1 ... Input buffer, 2 ... Change pixel detection / mode determination circuit, 4 ... Code table ROM, 5 ... Parallel / serial conversion circuit, 6 ... Shift register, 7 ... Timing control circuit, 8 ... Control Section, 20, 22 ... Interface circuit, 21 ... Multiplexer, 23, 41, 42, 43 ... Register, 44 ... Status information, 45 ... Pause request signal,
192 ... Parameter storage register file, 202 ... Multiplexer, 203 ... Switching signal.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hideyuki Shirai, Inventor Hideyuki Shimeguro 2-3-8, Meguro-ku, Tokyo Matsushita Densen Co., Ltd. (72) Inventor Toshiko Nishida 2-3-8 Shimeguro, Meguro-ku, Tokyo Matsushita Electric Transmission Co., Ltd.

Claims (1)

[Claims] 1. A reading means for scanning a target document to read image data, an image data storage means for temporarily storing several lines of the image data read by the reading means, and an image data storage means for storing the image data. Encoding means for encoding image data of several lines, detecting means for detecting the end of the target document read by the reading means, and image data read by the reading means once stored in the image data storage means, The number of unprocessed lines stored in the image data storage unit when the preset number of lines to be continuously encoded is sequentially encoded by the encoding unit and the detection unit detects the end of the target document. Is calculated and reset, and control means for causing the coding means to code this number of lines.