JPH09282305A - Digital data processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital data processor which is equipped with an SIMD type DSP and can flexibly cope with a process that is not suitable to the SIMD type DSP such as a multiple-operation mode and a sequential process. SOLUTION: This digital data processor is equipped with an arithmetic processing part constituted by using SIMD type DSPs 201 and 201, and a print core 204 and an error diffusion arithmetic processing core 208 as other arithmetic processing parts which perform specific arithmetic processes that are not suitable for processes by the DSP, and a data process is performed by distinctively using the DSPs 201 and 201, print core 204, and error diffusion arithmetic processing core 108 according to the process to be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital data processing device, and more particularly to a SIMD (Single Inst).
reduction Stream-multipl Da
ta stream) type digital signal processor (DSP; Digital Signal Procedures)
SOR) is used for the digital data processing device.

[0002]

2. Description of the Related Art Conventionally, in a digital copying machine, a digital facsimile, or a composite machine of these, a circuit for processing image data read by a scanner is ASI.
C (Application Specific Int)
Although it was realized by using an integrated circuit), with the progress of DSP in recent years, one using a DSP has appeared in a portion that requires high-speed processing of digital signals. As this type of device, there is one in which a modem function and an image processing function are realized by a single DSP (see Japanese Patent Laid-Open No. 4-37900).

[0003]

However, when the image processing is performed only by the DSP as in the technique disclosed in the above publication, a simple copy operation can be performed but the image read by the scanner is facsimile. The path control of the composite operation such as printing out the data from the printer controller while transmitting may not be realized due to the hardware limitation of the DSP. Also,
The DSP that can perform the image processing of the digital copying machine in real time is limited to the SIMD type. However, in the case of the algorithm that assumes the sequential processing like the error diffusion processing, the SIMD type processor is used. No parallel processing is possible. In addition, as a peripheral device such as a print processing device installed in the current digital copying machine,
Those requiring an AM or ROM and capable of performing processing only sequentially are not suitable for processing by a SIMD type processor. An object of the present invention is to solve the above-mentioned drawbacks of the conventional technique and to flexibly cope with processing that is not suitable for SIMD type DSP, such as a composite operation mode and sequential processing, with a device configuration including a SIMD type DSP. It is to provide a digital data processing device.

[0004]

In order to solve the above-mentioned problems, a digital data processing apparatus of the present invention, as described in claim 1, comprises an arithmetic processing section using a SIMD type digital signal processor, and With another arithmetic processing unit that performs a specific arithmetic processing that is not suitable for the processing in the arithmetic processing unit,
It is characterized in that the arithmetic processing unit is selectively used according to the processing to be executed to perform data processing. According to the digital data processing device configured as described above, S
The arithmetic processing suitable for the processing by the IMD type digital signal processor is performed by the arithmetic processing section including the SIMD type digital signal processor, and the specific arithmetic processing not suitable for the processing by the arithmetic processing section is different from the above-mentioned one. By performing the processing in the arithmetic processing unit, the device configuration is provided with the SIMD type DSP, and the SIMD type DSP such as the composite operation mode and the sequential processing is provided.
It can flexibly handle processing that is not suitable for. The arithmetic processing suitable for the SIMD type digital signal processor includes various image processing such as shading correction processing, filtering processing, γ correction processing, and gradation processing, as well as acoustic processing for generating reverberation sounds and echoes. is there. Also, S
The arithmetic processing that is not suitable for the IMD type digital signal processor includes error diffusion processing and sequential processing such as print image data generation processing.

The digital data processing device according to a second aspect is based on the device configuration according to the first aspect, and the error diffusion process is performed by the another arithmetic processing unit, so that the flexibility of the process by the DSP and the error diffusion process are performed. Achieve both processing functions. The digital data processing device according to claim 3 is premised on the device configuration according to claim 1, and by performing error diffusion processing in the another arithmetic processing unit, flexibility of processing by the DSP and print image data generation processing. Achieve both functions. The digital data processing device according to claim 4 is based on the device configuration according to any one of claims 1 to 3, and further includes a path control unit that controls data exchange with the outside through various path interface units. And DSP
It enables data to be exchanged with an external device or the like that operates at a clock different from that of. Therefore, for example, it is possible to realize the path control in the composite operation mode such as printing out the data from the printer controller while transmitting the image read by the scanner by facsimile.

[0006]

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 schematic front view showing an example of an embodiment of a digital copying machine in which the digital data processing device of the present invention is applied to a digital image processing device. As shown in FIG. 1, a device body 1 of a digital copying machine.
A contact glass 2 on which an original is placed is provided on the upper surface of the, and a reading optical system 10 is provided below the contact glass 2. The reading optical system 10 includes a light source 4, a reflector 5, a first mirror 3, a second mirror 6, a third mirror 7, a lens 8, and a line image sensor (CCD) 9, and the light from the light source 4 is emitted from the reading optical system 10. Is reflected upward by the reflector 5 to illuminate the original on the contact glass 2, and the reflected light from the original is reflected by the first mirror 3, the second mirror 6, and the third mirror 7.
The optical path is changed by, and the image of one line of the image is condensed on the CCD 9 by the lens 8. When reading the entire document at the same size, the light source 4, the reflector 5, and the first mirror 3 are integrally moved over the entire surface of the document in the direction of arrow A (sub-scanning direction) in the drawing, and The second mirror 6 and the third mirror 7 move at a speed slower than that of the light source 4 and move in a range smaller than the above-mentioned movement amount. When the magnification changes, the amount of movement of each mirror also changes, and the lens 8 also moves.

Image information of the original read by the CCD 9 is printed by an image forming unit 11 provided below the reading optical system 10. The image forming unit 11 includes a laser diode (LD) 22 that is modulated and driven according to image information, an optical system 23 that focuses laser light from the LD 22 to a predetermined position, and a reflecting mirror that reflects output light of this optical system. 24, the photosensitive drum 12 exposed by the beam from the reflecting mirror 24,
A charging charger 13 that uniformly charges the photosensitive drum 12 before exposure, developing devices 14 and 15 that attach toner to the electrostatic latent image by exposure and develop it, and transfer paper is fed to the transfer position at the same timing. Registration roller 27,
Transfer charger 1 for transferring the toner image on the photoconductor drum 12 to the transfer paper sent from the registration roller 27.
8. Separation charger 19 for separating the part of the paper after transfer from the photoconductor drum 12, a conveyor belt 30 for conveying the separated transfer paper, and fixing the toner image adhering to the transfer paper conveyed by the conveyor belt. A fixing device 31, a cleaning device 21 for removing the residual toner adhering to the surface of the photosensitive drum 12, and a paper cassette 3 in which a plurality of transfer papers of different sizes are set.
4, 35, 36, a paper feed roller 26 that takes out the paper one by one from each paper cassette 34, 35, 36 and sends it to the registration roller 27, and a discharge tray 33 that stores the transfer paper fixed by the fixing device 31. It consists of

In the image forming unit 11, the LD 2 is selected according to the image information.
2 is modulated and driven, and the laser beam emitted from the LD 22 reaches the photoconductor drum 12 which is charged in advance by the charging charger 13 via the optical system 23 and the reflecting mirror 24, and forms a latent image. This latent image reaches the position where the developing devices 14 and 15 face each other in accordance with the rotation of the photosensitive drum 12,
Toner development is performed on the latent image. The transfer sheets from the sheet cassettes 34, 35, 36 are fed from the registration rollers 27 at the same timing as the visible image formed by the toner development reaches the transfer position, and the transfer charger 18 at the transfer position causes the photosensitive drum 12 The upper toner image adheres to the paper. The transfer-completed paper is peeled off from the leading edge of the transfer belt 30 by the charge removal charger 19.
Sent up. The paper on the conveyor belt 30 is fixed to the fixing device 3.
1, the toner image is fixed on the paper surface by applying heat and pressure. The transfer sheet having been fixed is sent to the discharge tray 33.

FIG. 2 is a block diagram showing the configuration of the electrical system of the digital copying machine. In the figure, CCD 9, video processing unit 100, image processing unit (IPU) 2
00, CPU 300, text RAM 400, character generator ROM 500, editing unit I / F 60
1, frame memory I / F602, printer I / F60
3, a circuit configuration including an option input terminal 701 and an option output terminal 702 is shown. The video processing unit 100 includes an AMP 101 and an A / D converter 102.
The image signal read by the CCD 9 is composed of
After being amplified by 101, A / D converter 102 performs A / D conversion, and 8-bit digital image data DA synchronized with 10 MHz clock CK1 sent from IPU 200.
Output as TA0-7. Video processing unit 100
In contrast, the signal CCDSTN that determines the read timing of the CCD 9 together with CK1 is the image processing unit 20.
It has been sent from 0. IPU200 is the first DSP2
01, second DSP 202, timing controller 2
03, print core 204, first FIFO 205, second FIFO 206, CCD I / F 207, error diffusion calculation processing core 208, first selector (EDUSEL) 20
9 and a second selector (OPSEL) 210.

From the timing controller 203, the main scanning synchronizing signal, the main scanning gate signal, and the sub-scanning gate signal give appropriate delays to the respective blocks such as the first and second DSPs 201 and 202 and the print core 204. Is output. The first and second DSPs 201,
202 has 20 MH with 32 bits input and 32 bits output
A SIMD type DSP capable of inputting and outputting data with z is assumed. First and second FIFOs are connected to these input / output terminals.
Inputs and outputs of 205 and 206 and various interfaces (I / F) are connected. The first DSPD 201 receives the 8-bit image data DATA0 to DATA7 sent from the video processing unit 100 as an input, and performs black offset correction,
Shading correction, MTF correction, and electrical scaling processing in the main scanning direction are sequentially performed to output image data.

Here, the black offset correction is a correction for subtracting the black level of the dark current of the CCD 9 from the image data. In the shading correction, in order to eliminate unevenness in the light amount of the light source in the main scanning direction and unevenness in sensitivity between pixels of the CCD 9, a white reference plate having a uniform density provided at the end portion of the contact glass 2 before the scanning of the original is used. This is a correction performed by reading, storing the data for each pixel, and dividing the image data during reading the document by the stored white plate data for each pixel. The MIF correction is to correct optical frequency characteristic deterioration and the like with a two-dimensional spatial filter. The electrical scaling is a process of changing the magnification of an image by a calculation process when the lens 8 is fixed, and is performed by a correction calculation by the three-dimensional convolution method in the scaling circuit unit of the DSP 201.

The first FIFO 205 stores shading data obtained by reading the white reference plate during shading correction. The second FIFO 206 performs speed conversion associated with scaling. The control signal of the first FIFO 205 is given from the timing controller 03. The control signal of the second FIFO 206 is the first DSP2.
01 output signal terminal. First DSP 20
The processing programs executed by the first and second DSPs 202 are pre-downloaded via the CPU I / F 207, and the CPU 300 performs processing according to the operation mode by switching the values of MODE 1 and 2 through the CPU I / F 207. Is able to.
For example, the type and strength of the filter can be switched according to the image quality mode, the order of scaling with the filter can be switched, and the shading method can be switched. The image data processed by the first DSP 201 is the EDUS connected to the editing unit I / F 601.
It is input to the second DSP 202 through the EL 209.
When EDUSEL 209 is off, the first DSP 201
Is directly connected to the output of the second DSP 202. ED
When the USEL 209 is on, the first DSP 201 output is sent to the editing unit I / F 601 and the editing unit I
The signal from / F601 is given to the second DSP 202. In the second DSP 202, γ correction and binarization processing,
Image quality processing such as binary and multi-value dither, and print image composition processing are performed according to a program.

The print core 204 is a dedicated hardware (ASI) designed to be suitable for print image signal generation processing.
C) and is connected to the image input terminal of the second DSP 202. The print image signal generation process is a process of sequentially accessing the text RAM 400 and reading a print signal from the character ROM 500 as a character generator, and is not suitable for parallel processing of the DSP unit. Therefore, in this embodiment, the print core 204 is the CPU.
Under the control of 300, the text RAM 400 is accessed to read the print signal from the character generator ROM 500, and a 1-bit print image signal is output to the second DSP in accordance with the gate signal from the timing controller 203.
It is configured to output to 202.

The error diffusion calculation processing core 208 is constituted by dedicated hardware (ASIC) designed to be suitable for the error diffusion calculation processing, and is connected to the input / output terminal of the second DSP 202. The error diffusion process is to distribute the quantization error by a 3 × 6 matrix as shown in FIG. This is a process of quantizing the error value distributed from the pixel of interest and the surrounding pixels and further distributing the error. Since the basic process is the sequential process in the main scanning direction, it is suitable for SIMD type architecture. Absent. Therefore, when the data requiring the error diffusion processing is input, the second DSP 202 outputs the data to the error diffusion arithmetic processing core 208 as it is, and obtains the data after the error diffusion processing from the error diffusion arithmetic processing core 208. To do.

Those not suitable for SIMD type architectures, whose functions are fixed and whose circuits are completed are realized by dedicated hardware and removed from the internal processing of the DSP. Resources can be used effectively. The image data processed by the second DSP 202 is output to the option output terminal 702 or the printer I / F 603. Then, the image data output from the option output terminal 702 is transmitted to the outside via a FAX modem or the like not shown. From the second DSP 202 to the printer I / F
Image data is sent to 603 through OPSEL 210. The OPSEL 210 switches the output according to the mode of the second DSP 202, and outputs the option input terminal 701.
The image data input from the printer can be sent to the printer I / F 603. At this time, the clock can also be switched to flow to the printer I / F 603.

As described above, in the present embodiment, in addition to the DSP core, the video path switching circuits (EDUSEL, OPS).
EL) allows interfacing with editing units and options running on different clocks. Functions such as EDUSEL209 are DSP20
It can be realized by switching in the internal processing of Nos. 1 and 202, but in that case, it is necessary to use at least 16 input / output pins of the DSP section. According to the configuration of this embodiment, the function can be realized with the minimum number of DSP input / output pins used. The printer I / F 603
The image data output from the LD modulation plate 22a is sent to a printer control unit (not shown) of the image forming unit 11 and subjected to speed conversion according to the write clock.
Sent to In the LD modulation plate 22a, this 8-bit 256
The pulse width and the amount of current applied to the LD 22 are controlled according to the gradation image data. IPU20
Shares the address bus and the data bus with the main control board of this digital copying machine, and the communication is performed via this. The main control board is the scanner 10 and the image forming unit 11.
It also controls the motor control, various clutches and solenoids.

In the above structure, when the image is read in the normal original image reading mode, the original is set on the contact glass 2 with the image side down and the start button is pressed. As a result, a scan start signal is issued from the CPU 300 to the IPU 200, and the gate signal FGATE indicating the effective image range in the sub-scanning direction becomes active. After that, the moving body including the first mirror 3, the light source 4, and the reflector 5 starts moving to the left in FIG. 1, and the sub-scan for the document is performed. The reflected light (reading light) from the document illuminated by the light source 4 reaches the CDD 9 via the first mirror 3, the second mirror 6, the third mirror 7, and the lens 8 in order. CD
D9 converts incident light into an electric signal. The signal from the CDD 9 is A / D converted by the video processing unit 100 and then IP
It is sent to U200. The data sent to the IPU 200 includes black offset processing, shading correction processing, MTF.
Γ after the correction processing and the electrical scaling processing in the main scanning direction
Image quality processing such as correction and dither processing and error diffusion processing is performed. Then, it is sent to the printer control unit of the image forming unit 11. In normal copying, the operation start signal DFGATE of the image forming unit 11 is set to ACT
It becomes VE, and writing to the image forming unit 11 is performed.

FIG. 4 is a block diagram of the character image synthesizing unit. The character image synthesizing unit includes a print core 204 and a text RA.
The M214, the character generator ROM 215, and the synthesis processing unit of the second DSP 202. As shown in FIG. 4, the print core 204 includes address counters 211 and 212 and a memory control unit 213. The timing controller 203 supplies the print core 204 with an Fgate signal, an Lgate signal, and an Lsyn signal.
The c signal and the clock signal are given an address signal, a data signal, and a bus control signal from the CPU 300. One address counter 211 is a sub-scanning address counter and counts the number of lines during the Fgate assert period. The other address counter 212 is a main scanning address counter, and counts the image data valid period during the Lgate assert period. Memory control unit 213
Outputs character code data based on a signal from the CPU 300 and writes it in the text RAM 400,
A control signal corresponding to the address signals from the address counters 211 and 212 is given to the text RAM 214. The text RAM 214 outputs the character code data to the character generator ROM 215 according to the control signal from the memory control unit 213.

The character generator ROM 215 stores bit images of characters at addresses in ASCII code order. Character generator ROM
A character code 215 is accessed with the character code read from the text RAM 214 corresponding to the position on the original as the upper address and the lower bits of the addresses output from the main / sub-scanning address counters 211 and 212 as the lower address, and combined with the original. The bit image of the character to be reproduced by the second DSP 20
It is output to the combining unit in 2. The second DSP 202 synthesizes the bit image data sent from the character generator ROM 215 and the image data sent from the first DSP 201, and outputs it.

In this way, the text RAM 400 is sequentially
Is provided separately from the DSPs 201 and 202 for performing print image data generation processing for reading a print signal from the character generator ROM 500 by accessing the.
Bit image of characters from 500 and the first DSP20
SI such as synthesis processing and dither processing with image data from 1
By mainly performing the processing suitable for the MD type DSP, the functions of the first and second DSPs 201 and 202 can be fully exerted and the image processing can be performed at high speed. Note that the present invention is not limited to the configuration of the above-described embodiment, and the entire IPU 200 shown in FIG.
It goes without saying that they may be integrated as an IC. In the above embodiment, the case where the digital data processing device of the present invention is applied to the digital image processing device of the digital copying machine has been described. It goes without saying that it is also applicable. Furthermore, the digital data processing device of the present invention is an effect device that adds various acoustic effects such as reverberation and distortion to an input acoustic signal, and a digital sound source device that processes the input signal into an acoustic signal of an arbitrary waveform or component. It can be effectively used as a data processing device.

[0021]

In summary, according to the present invention, the following excellent effects can be obtained. In the digital data processing device according to the first aspect of the present invention, the arithmetic processing suitable for the processing in the SIMD type digital signal processor is performed by the arithmetic processing section including the SIMD type digital signal processor, and the arithmetic processing section By performing a specific arithmetic processing that is not suitable for the above processing in another arithmetic processing unit, it is possible to perform processing that is not suitable for the SIMD type DSP such as a composite operation mode or sequential processing in a device configuration including a SIMD type DSP. We can respond flexibly. In the digital data processing device according to the second aspect of the present invention, the flexibility of the processing by the DSP and the realization of the error diffusion processing function can both be achieved by performing the error diffusion processing in the another arithmetic processing unit.

In the digital data processing device according to the third aspect of the present invention, the flexibility of the processing by the DSP and the realization of the print image data generation processing function are both achieved by performing the error diffusion processing in the separate arithmetic processing unit. Can be made.
In the digital data processing device according to the invention described in claim 4, an external device operating with a clock different from that of the DSP by further comprising a path control part for controlling data exchange with the outside through various path interface parts. Data can be exchanged with other devices, and path control in the combined operation mode can be realized.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an example of an embodiment of a digital copying machine in which a digital data processing device of the present invention is applied to a digital image processing device.

FIG. 2 is a block diagram showing a circuit configuration of an electric system of the digital copying machine shown in FIG.

FIG. 3 is a diagram showing an example of an error matrix in error diffusion processing.

FIG. 4 is a block diagram of a character image combining unit.

[Explanation of reference numerals] 1 main body of digital copying machine, 2 contact glass, 4 light source, 10 reading optical system, 9 CCD, 10
Reading optical system, 100 Video processing unit, 200
Image processing unit (digital data processing device), 20
1 DSP (Digital Signal Processor), 204
Print core (another arithmetic processing unit), 208 Error diffusion arithmetic processing core (another arithmetic processing unit), 209 EDUSEL (pass control unit), 210 OPSEL (pass control unit), 30
0 CPU, 400 text RAM, 500 character generator ROM, 601 editing unit I /
F, 602 frame memory I / F, 603 printer I / F, 701 option input terminal, 702 option output terminal

Claims (4)

[Claims] 1. An arithmetic processing unit including a SIMD type digital signal processor, and another arithmetic processing unit for performing specific arithmetic processing not suitable for the processing in the arithmetic processing unit. A digital data processing device characterized by performing data processing by properly using both arithmetic processing units. 2. The digital data processing device according to claim 1, wherein the specific arithmetic processing is error diffusion processing. 3. The digital data processing apparatus according to claim 1, wherein the specific arithmetic processing is print image data generation processing. 4. The digital data processing device according to claim 1, further comprising a path control unit that controls exchange of data with the outside through various path interface units.