JP2001245159A - Device and method for image data processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize sure transfer in real time for compressed data, even if the data amount generated by compression processing is not fixed. SOLUTION: In method for image data processing, input image data is compressed, subjecting to JPEG processing part as compressed image data, the generated compressed image data are outputted toward a buss, and determination made as to whether the creating speed for the compressed image data at the JPEG process part is faster than the output speed for the compressed image data towards the buss (steps S303, S304, S305). When the determination is made that the generation speed is higher than the output speed, a low- resolution image data is generated by lowering the resolution of the input image data, then the compression processing and the output processing to the bus for the low-resolution image data are re-processed (steps S307, S309).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image data processing apparatus and method for compressing image data obtained by a scanner or the like in real time and outputting the obtained data to a bus for predetermined processing.

[0002]

2. Description of the Related Art There has been proposed an image processing apparatus capable of sharing a scanner, a printer, and a file system on a network by using a network interface.

In this case, an image processing apparatus and devices such as a scanner, a printer, a memory, and a network interface for satisfying a user's request are connected to a common system bus via dedicated interfaces. Then, a means for controlling a data transfer on a system bus between devices realizing the selected function by selecting a function to be operated from a user interface according to a user's needs is common.

[0004] For example, to realize a copy operation,
First, a signal input to the apparatus from a scanner device is taken into a memory via a system bus. The copying operation is performed by outputting data from the memory to the printer at the same time as the completion of the scanning operation.

In the above configuration, each device operation is performed through a common system bus. Since the transfer rate on the system bus is limited, the system is provided with means for recognizing that the transfer rate of output data from each device has exceeded the transfer rate of the system bus. When it is recognized that the transfer rate of the output data exceeds the transfer rate of the system bus, control is performed to stop the transfer operation to the system bus, so that a transfer error is prevented.

An operation of processing data read from a memory in the system and then writing the data to the memory again,
In the case of an operation that transfers data to the memory of the system external device via the network, when the transfer rate of each device reaches the maximum transfer rate of the system bus, the output operation of the device is stopped, and a transfer error occurs. Can be blocked.

However, in a process such as a scanner operation in which data read from a scanner must be transferred in real time, even if the transfer is stopped during the data transfer, the input data transfer from the scanner cannot be stopped. Therefore, the data during the stop of the transfer is not transferred correctly, and the data is overwritten in a buffer or the like provided in the middle of the transfer, so that the data is dropped.

[0008]

As a method for solving the above-mentioned problem, it is conceivable to perform compression processing on image data read by a scanner to reduce the amount of data and thereby reduce the transfer rate. For example, in an image processing apparatus having a scanner, a printer, a network interface, a memory, and an image processing system, a configuration may be considered in which JPEG compression of scan image data is performed, the compressed data is transferred to a memory, and stored. Can be

However, a predetermined quantization table for determining a compression ratio in JPEG compression is used. That is, in JPEG compression, the data size after compression varies depending on the type of original document to be read by the scanner and cannot be determined in advance. For this reason, in the above system, JPEG compression is performed to transfer image data input from the scanner to the memory via the system bus. However, depending on the type of the original, the maximum transfer of the system bus is performed. There is a possibility that the rate will be exceeded.

In the above-mentioned "prior art", the data read from the memory is processed in the system and then written in the memory again, or the data is transferred to the memory of the system external device through the network. Operation can be handled by setting the transfer rate of the output data of the device to the maximum transfer rate of the system bus or less by a control signal between the devices in advance. Cannot determine the transfer rate of the compressed data.

The present invention has been made in view of the above-mentioned problems, and enables reliable transfer of data after compression processing in real time even when the amount of data generated by compression processing is not determined. The purpose is to:

[0012]

An image data processing apparatus according to an aspect of the present invention for achieving the above object has, for example, the following arrangement. That is, compression means for performing compression processing on image data scanned and input from a scanner to generate compressed image data, output means for outputting the compressed image data generated by the compression means onto a bus, First determining means for determining whether the generation speed of the compressed image data is higher than the output speed of the compressed image data in the output means, and the first determining means determines that the generation speed exceeds the output speed. In this case, the resolution of the input image data is reduced and rescanning is performed by the scanner to generate low-resolution image data, and the processing by the compression unit, the output unit, and the determination unit is performed again on the low-resolution image data. Reprocessing means for causing

Further, an image data processing method according to another aspect of the present invention for achieving the above object includes, for example, the following steps. That is, a compression step of performing compression processing on image data scanned and input from a scanner to generate compressed image data, an output step of outputting the compressed image data generated in the compression step to a bus, A first determining step of determining whether the generation speed of the compressed image data is higher than the output speed of the compressed image data in the output step; and the first determining step determines that the generation speed exceeds the output speed. In this case, the resolution of the input image data is reduced, the scanner is re-scanned to generate low-resolution image data, and the low-resolution image data is subjected to the compression, output, and determination steps again. And a re-processing step.

[0014]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In the system of the present invention described below, compression processing based on the JPEG standard is performed before image data input from a scanner is transferred to a system bus, and transfer is performed after reducing the data amount. By doing so, the data can be transferred to the memory via the system bus.

In this embodiment, the problem of the real-time transfer of the JPEG-compressed code data via the system bus, that is, since the amount of data after compression cannot be determined, the transfer rate of the system bus is reduced. The following measures are taken to deal with the problem that the rate may be exceeded. That is, when the transfer rate of the compressed data exceeds the maximum transfer rate of the system bus, the system provides a means for recognizing this situation, and after recognizing that the system has been set to lower the resolution, By performing the operation of reading the same original again from the scanner, JPEG compression is performed on smaller image data at the time of rescanning, the data amount of the code after the compression processing can be reduced, and the data transfer rate can be reduced. In this way, by setting the resolution conversion so that the transfer rate of the compressed data does not exceed the maximum transfer rate of the system bus, it is possible to transfer all data read from the scanner.

<Overall Configuration> FIG. 1 is a block diagram showing the overall configuration of the image processing apparatus according to the present embodiment. The control unit 2000 includes a scanner 207 serving as an image input device.
0 and a printer 2095 as an image output device, while a LAN 2011 or a public line (WAN) 20
51 is a controller for inputting and outputting image information and device information by connecting to the controller 51. A CPU 2001 is a controller that controls the entire system. RAM 20
Reference numeral 02 denotes a system work memory for operating the CPU 2001, and also serves as an image memory for temporarily storing image data. ROM 2003 is a boot ROM,
Contains the system boot program. HDD
A hard disk drive 2004 stores system software and image data.

An operation unit I / F 2006 is an interface unit between the operation unit 2012 and the system bus and 2007, and transmits image data displayed on the operation unit 2012 to the operation unit 2.
012, and also serves to transmit information input by the user of the system from the operation unit 2012 to the CPU 2001. Network 2010 is LAN 2011
, And input and output information. Modem (MODEM) 20
Reference numeral 50 is connected to a public line 2051 to input and output information. The above devices are arranged on the system bus 2007.

An image bus interface (Image Bus I)
/ F) 2005 is a bus bridge that connects the system bus 2007 to the image bus 2008 that transfers image data at high speed, and converts the data structure. The image bus 2008
It is composed of a PCI bus or IEEE1394. The following devices are arranged on the image bus 2008.

Raster image processor (RIP) 2
Reference numeral 060 expands the PDL code into a bitmap image. The device I / F unit 2020 connects the scanner 2070 and the printer 2095, which are image input / output devices, to the control unit 2000, and performs synchronous / asynchronous conversion of image data. Note that an image processing unit 1 is provided between the device I / F 2020 and these image input / output devices. The image processing unit 1 performs correction, processing, editing, and the like on input / output image data. The image rotation processing unit 2030 rotates image data. The image compression processing unit 2040 uses JPEG for multi-valued image data and JBI for binary image data.
G / MMR / MH compression / expansion processing is performed. The scanner image processing unit 2080 and the printer image processing unit 2090 will be described later with reference to FIGS. 7 and 8, respectively.

Reference numeral 2071 denotes an interface cable for connecting the scanner 2070 and the image processing unit 1.
Reference numeral 2096 denotes an interface cable for connecting the printer 2095 and the image processing unit 1.

<Image Input / Output Group> FIG. 2 is a diagram showing an overview of the image input / output device according to the present embodiment. The scanner unit 2070, which is an image input device, illuminates an image on paper serving as a document and scans a CCD line sensor (not shown) to convert the image into an electric signal as raster image data. The manuscript paper is set on a tray 2073 of a manuscript feeder 2072, and when the apparatus user instructs reading and starting from the operation unit 2012, the CPU 2001 in the control unit 2000 gives an instruction to the scanner 2070. The document is fed one by one and the reading operation of the document image is performed.
Note that communication between the scanner 2070 and the control unit 2000 is performed via the interface cable 2071.

A printer unit 209 serving as an image output device
Reference numeral 5 denotes a part for converting raster image data 2096 into an image on paper, which is an electrophotographic method using a photosensitive drum or a photosensitive belt, and which directly discharges an image onto paper by discharging ink from a micro nozzle array. And the like, but any method may be used. The start of the printing operation is started by an instruction 2096 from the controller CPU 2001. The printer unit 2095 has a plurality of paper feed stages so that different paper sizes or different paper orientations can be selected, and includes paper cassettes 2101, 2102, 2103, and 2104 corresponding thereto.
The paper discharge tray 2111 receives the printed paper.

<Operation Unit> FIG. 3 is a diagram showing an overview of the operation unit 2012. In the operation unit 2012, a touch panel sheet is pasted on the screen of the LCD display unit 2013 to display an operation screen of the system, and when a displayed key is pressed, the position information is transmitted to the controller CPU 2001. A start key 2014 is used to start a document image reading operation. In the center of the start key 2014, a two-color LED 20 of green and red
The start key 2014 indicates whether or not the start key 2014 can be used. A stop key 2015 functions to stop an operation in operation.
An ID key 2016 is used to input a user ID of a user. A reset key 2017 is used to initialize settings from the operation unit.

<Image Compression Processing Unit> FIG.
FIG. 3 is a block diagram showing a configuration of a forty. In FIG. 4, the image bus I / F controller 2041 is
8 to control the bus access sequence, and the input buffer 2042 and the output buffer 2045.
Timing control for exchanging data with
The image compression unit 2043 performs control such as mode setting. The processing procedure of the image compression processing unit 2040 will be described below.

The CPU 200 via the image bus 2008
1 to the image bus I / F controller 2041 for setting for image compression control. With this setting, the image bus I /
The F controller 2041 sets the settings required for image compression (for example, MMR compression / JBIG
Elongation etc.). After making the necessary settings,
U2001 permits the image bus I / F controller 2041 to transfer image data. Subject to this permission,
The image bus I / F controller 2041 is a RAM 2002
Alternatively, transfer of image data from each device on the image bus 2008 is started.

The received image data is stored in an input buffer 20.
The image is temporarily stored in the storage unit 42, and the image is transferred at a constant speed in response to an image data request from the image compression unit 2043. On this occasion,
The input buffer 2042 is an image bus I / F controller 2
It is determined whether or not image data can be transferred between both the image compression unit 2043 and the image compression unit 2043. If it is impossible to read image data from the image bus 2008 and write an image to the image compression unit 2043, Control is performed so as not to transfer data (hereinafter, such control is referred to as handshake).

The image compression section 2043 temporarily stores the received image data in the RAM 2044. This is because, when image compression is performed, several lines of data are required depending on the type of image compression processing to be performed. To compress the first one line, several lines of image data must be prepared. This is because image compression cannot be performed unless the image is compressed. The image data subjected to image compression is immediately sent to the output buffer 2045. The output buffer 2045 performs handshaking with the image bus I / F controller 2041 and the image compression unit 2043, and transfers image data to the image bus I / F controller 2041. The image bus I / F controller 2041 transfers the transferred compressed (or decompressed) image data to the RAM 2002 or each device on the image bus 2008. Such a series of processing is performed by CP
This processing is repeated until there is no processing request from U2001 (when processing of the required number of pages is completed) or until a stop request is issued from the image compression unit 2043 (for example, when an error occurs during compression and decompression).

<Image Rotation Processing Unit> FIG. 5 is a block diagram showing the structure of the image rotation processing unit 2030. Image bus I /
The F controller 2031 is connected to the image bus 2008 to control the bus sequence and the image rotation unit 2.
032 and control for setting the mode and the like, and the image rotation unit 20
32, a timing control for transferring the image data. The processing procedure of the image rotation processing unit 2030 will be described below.

The CPU 200 via the image bus 2008
1 to the image bus I / F controller 2031 to make settings for image rotation control. With this setting, the image bus I /
The F controller 2041 performs settings necessary for image rotation (for example, image size, rotation direction, angle, and the like) for the image rotation unit 2032. After making the necessary settings,
U2001 permits image data transfer to the image bus I / F controller 2031. Subject to this permission,
The image bus I / F controller 2031 is a RAM 2002
Alternatively, transfer of image data from each device on the image bus 2008 is started.

Here, the size of the image to be rotated is set to 32 × 32 (bit) with 32 bits as its size.
When transferring image data onto the image bus 2008, image transfer is performed in units of 32 bits (the image to be handled is assumed to be binary).

As described above, in order to obtain a 32.times.32 (bit) image, the above-described unit data transfer needs to be performed 32 times, and image data must be transferred from discontinuous addresses. (See FIG. 12) The image data transferred by the discontinuous addressing is written to the RAM 2033 so as to be rotated to a desired angle at the time of reading. For example, in the case of a 90-degree counterclockwise rotation, the initially transferred 32-bit image data is written in the Y direction as shown in FIG. By reading in the X direction at the time of reading, the image is rotated.

Image rotation of 32 × 32 (bit) (RAM
After the completion of the writing to the image rotation unit 2033, the image rotation unit 20
The image bus I / F controller 203 reads out image data from the RAM 2033 by the above-described readout method.
1 to transfer the image. The image bus I / F controller 2031 that has received the rotated image data transfers the data to the RAM 2002 or each device on the image bus 2008 by continuous addressing.

Such a series of processing is repeated until there is no processing request from the CPU 2001 (when processing of the required number of pages is completed).

<Image Processing Unit 1> FIG. 6 is a block diagram showing the configuration of the image processing unit 1. As shown in FIG. 6, the image processing unit 1 includes a data selector unit 2 and a JPEG processing unit 3, and includes a scanner 2070, a printer 2095, a scanner image processing unit 2080, and a printer image processing unit 209.
0, the device I / F unit 2020 is connected.

The data selector 2 includes a scanner image processor 2080, a printer image processor 2090, a device I
/ F section 2020 and JPEG processing section 3 are connected, and include a bus selector for switching the bus for each operation, and a buffer for switching the bus and adjusting the transfer frequency of each bus.

In the data selector unit 2, in the case of a scanner operation, the bus is switched so that the scanned image input from the scanner 2070 is output to the device I / F unit 2020 via the scanner image processing unit 2080. As a result, the image data read from the scanner 2070 is output to the device I / F unit 2020 after being subjected to predetermined processing by the scanner image processing unit 2080.

In the case of a printer operation, the bus is switched by the data selector unit 2 so that the data output from the device I / F unit 2020 is output to the printer 2095 via the printer image processing unit 2090. .

Further, in the case of JPEG compression processing, the bus is switched by the data selector unit 2 so that the scanned image input from the scanner 2070 is output to the JPEG processing unit 3 via the scanner image processing unit 2080. . As a result, the scanned image read from the scanner is processed by the scanner image processing unit 2080 and then output to the JPEG processing unit 3. Then, the bus is switched so that the JPEG code data compressed by the JPEG processing unit 3 is output to the device I / F unit 1 in the data selector unit 2, and the device I / F
Output to the unit 2020.

In the case of JPEG decompression processing, device I /
The JPEG code data output from the F unit 2020 is
The bus is switched so as to be output to the JPEG processing unit 3 in the data selector unit 2 and output to the JPEG processing unit 3. The bus is switched so that the JPEG decompressed image decompressed by the JPEG processing unit 3 is output to the device I / F unit 1 in the data selector unit 2, and the device I / F
Output to the unit 2020.

<Scanner Image Processing Unit> FIG. 7 is a block diagram showing the configuration of the scanner image processing unit 2080.

Scanner image bus controller 2081
Controls the bus access sequence between the scanner 2070 and the input buffer 2087, and between the output buffer 2088 and the data selector unit 2, controls each device in the scanner image processing unit 2080, and generates a timing signal. The filter processing unit 2082 performs a convolution operation using a spatial filter. The editing unit 2083
For example, a closed area surrounded by a marker pen is recognized from input image data, and image processing such as shadowing, shading, and negative / positive inversion is performed on the image data in the closed area.
When changing the resolution of the read image, the scaling unit 2084 performs interpolation calculation in the main scanning direction of the raster image to perform enlargement and reduction. The magnification in the sub-scanning direction is changed by changing the scanning speed of an image reading line sensor (not shown). Brightness / density conversion unit 208
Reference numeral 5 refers to a predetermined table and converts the image data, which is the read luminance data, into density data. The binarizing unit 2086 binarizes the multi-value grayscale image data by error diffusion processing or screen processing. In addition,
When outputting multivalued image data, binarization is not performed. The processed image data is transferred to the data selector 2 via the output buffer 2088.

<Printer Image Processing Unit> FIG. 8 is a block diagram showing the structure of the printer image processing unit 2090.

Printer image bus controller 2091
Is between the data selector unit 2 and the input buffer 2094,
In addition to controlling a bus access sequence between the output buffer 2097 and the printer 2095, it controls each device in the printer image processing unit 2090 and generates a timing signal. The resolution conversion unit 2092 is
The resolution conversion for converting the image data provided from 2011 or the public line 2051 into the resolution of the printer 2095 is performed. The smoothing processing unit 2093 performs a process of smoothing jaggies (roughness of an image appearing at a black-and-white boundary such as an oblique line) of the image data after the resolution conversion.

<Device I / F Unit> FIG.
FIG. 3 is a block diagram illustrating a configuration of an F unit 2020.

In FIG. 9, an image bus I / F controller 2021 is connected to the image bus 2008, controls the bus access sequence, and controls the device I / F.
It controls each device in the section 2020 and generates a timing signal, and further generates a control signal to the external data selector section 2.

The image bus output buffer 2022 temporarily stores the image data sent from the data selector 2 and outputs the image data in synchronization with the image bus 2008. Serial-parallel / parallel-serial conversion 2023
The image bus 2020 arranges or decomposes the image data stored in the image bus output buffer 2022 in order.
08 to a data width that can be transferred. The parallel serial / serial / parallel conversion 2024 is connected to the image bus 200.
8 is decomposed or arranged in order and converted into a data width that can be stored in the image bus input buffer 2025. Image bus input buffer 2025
Temporarily stores the image data sent from the image bus 2008, and outputs the stored image data in synchronization with the data selector unit 2.

When the image bus 2008 is a PCI bus, three image data are stored in the image bus output buffer 2022.
When two or more bits are input, the image data is sent to the serial / parallel / serial / serial converter 2023 from the buffer for the first 32 bits in a first-in first-out manner, and is converted into 32-bit image data. Transfer to

Further, the 32-bit image data sent from the image bus is received by the image bus I / F controller and converted into a parallel-serial / serial-parallel converter 202.
4 and is decomposed into image data of the number of input data bits of the data selector 2 and stored in the print buffer 2025.

The image bus 2008 is connected to the IEEE 139.
In the case of No. 4, the image data of the image bus output buffer 2022 is sent from the buffer to the serial / parallel / serial / serial converter 2023 on a first-in first-out basis, and is converted into serial image data.
Through to the image bus 2008.

Further, serial image data sent from the image bus is received by the image bus I / F controller, and is converted into a parallel serial / serial / parallel conversion 2024.
To convert the data into image data of the number of input data bits of the data selector 2 and store it in the image bus input buffer 2025. Then, in synchronization with the timing signal sent from the data selector 2, the image data in the buffer is sent to the data selector 2 on a first-in first-out basis.

<JPEG Processing Unit> In the present embodiment, the JP
PM-35 is used in the JPEG processing unit 3 manufactured by Pixel Magic for EG codec processing. This is the image transfer frequency from the scanner (2 in this embodiment).
General-purpose J that can perform JPEG compression and decompression at 2 MHz)
PEG codec chip. Scanner image processing unit 2
The image data output from the 080 is data of three colors, each having an 8-bit width, and a total of 24-bit width is input to the PM-35.
After the compression processing is performed, the JPEG code data is output with a 16-bit width. Note that setting values such as a quantization table and a Huffman table used for the JPEG calculation are used in the calculation by setting them in a PM-35 internal register before the scan image processing operation. Hereinafter, the PM-35 JPEG codec chip is referred to as a JPEG codec chip 4.

FIG. 10 is a diagram for explaining communication between the data selector 2 and the JPEG processor 3 in the image processor 1. As described above, the JPEG processing unit 3
A G codec chip 4 is provided.

The JPEG codec chip 4 is also provided with buffers for input and output (not shown) inside the JPEG codec chip 4, and inputs and outputs data to a JPEG input buffer 21 and a JPEG output buffer provided in the data selector 2. 22.

Control signals for input data in the JPEG codec chip 4 include an Irql signal as an input request signal and an Iackl signal as an input enable signal. The Irql signal and the Iackl signal are always “High” before the start of the image processing operation.

The Irql signal is transmitted to the JPEG codec chip 4
"Low" if the input buffer inside is not full and data can be input; "High" if input is not possible
And output from the JPEG codec chip 4 to the buffer controller in the data selector 2. Iac
The kl signal is a signal which becomes “Low” when the JPEG input buffer in the data selector unit 2 is not empty and data can be output, and becomes “High” when output is not possible. To the JPEG codec chip 4. The JPEG codec chip 4 outputs the Irql signal “Low” and outputs the Iackl signal “Low”.
Only after receiving the data, data input from the data selector unit 2 is performed.

To control the output data of the JPEG codec chip 4, an Orql signal which is an output request signal,
There is an Oackl signal which is an output enable signal. The Orql signal and the Oackl signal are always “High” signals before the start of the image processing operation.

The Orql signal is output to the JPEG codec chip 4
Is low when the output buffer is not empty and data can be output, and high when data cannot be output, and is output from the JPEG codec chip 4 to the buffer controller in the data selector 2. Is done. The Oackl signal is “Low” when the JPEG output buffer in the data selector unit 2 is not full and data can be input, and becomes “High” when input is not possible. Is output to.

The JPEG codec 4 uses the Orql signal “Lo
w ", and the data is output to the data selector 2 only after receiving the Oackl signal" High ".

During operation of the JPEG codec chip 4, I
When the rql signal becomes “High”, the JPEG input buffer 21 in the data selector 2 is
JPEG processing unit 3 even if image data is received from 0
Will not be able to output. In this case, before the data size of the JPEG input buffer 21 (in this embodiment, 48 words of 24 bits width / word) becomes full, I
When the rql signal switches from “High” to “Low”, the image data is transferred to the JPEG compression unit 3 without being overwritten inside the JPEG input buffer 21. However, if the Irql signal is "High" for a time exceeding the data size of the JPEG input buffer 21, the JPE
Data overwriting occurs inside the G input buffer 21. Therefore, even if the Irql signal is subsequently switched to "Low", the data finally stored in the memory such as the RAM 2002 is such that the data is lost due to such overwriting.

This is because there is a control signal for handshake such as an enable signal for a request signal between the JPEG codec chip 4 and the data selector unit 2, whereas an input signal from the scanner 2070 is This is because data transfer cannot be temporarily stopped.

The following can be considered as the main causes of the Irql signal becoming “High” during the operation of the JPEG codec chip 4. (1) One is that the internal compression calculation process cannot keep up with the data input transfer to the JPEG codec chip 4,
This is a case where the input buffer of the JPEG codec chip 4 overflows. In the JPEG compression operation,
Since the amount of JPEG code data to be output changes depending on the type of input image data, the set quantization table value, and the processing method, such a situation may occur when the JPEG code data size becomes extremely large. There is. (2) The other case is that the Oackl signal does not switch from “High” to “Low” even though the compression operation processing and the operation result output processing inside the JPEG codec chip 4 are in time. This is because the image bus output buffer 2022 in the device I / F 2020 located ahead of the data selector 2 is full.

The case (2) will be further described.
The image bus output buffer 2022 is formed of a buffer memory, and when data is input, the image bus I
The write counter of the buffer memory is counted up by the / F controller 2021, and data is stored at the address indicated by the write counter. When output, the read counter of the buffer memory is counted up by the image bus I / F controller 2021, and data is read from the address indicated by the read counter. Image bus I / F controller 20
Numeral 21 constantly monitors the values of the write counter and the read counter. When the difference between the counter values reaches a predetermined value, data output is started. When the status is determined, the data input is stopped to prevent the data from overflowing from the buffer memory.

As a result, the data selector 2 cannot output data to the image bus output buffer 2022,
JP when the JPEG output buffer 22 is full
Data from the EG processing unit 3 cannot be input. As a result, the JPEG codec chip 4 cannot continue the processing, and Irql becomes “High”.

The full state of the image bus output buffer 2022 occurs because the output transfer to the image bus 2008 cannot keep up with the input transfer of the image bus output buffer 2022. That is, it occurs when the transfer rate of the output data from the JPEG processing unit 3 is high and exceeds the transfer rate of the image bus 2008.

In such a case, the Irql signal of the JPEG codec chip 4 becomes “High”. If the “High” state of the Irql signal continues until data larger than the data size of the JPEG input buffer 21 in the data selector unit 2 is stored, data is lost as described above, so that correct transfer cannot be performed.

Therefore, in the present embodiment, “H” of the Irql signal
If the “igh” state continues for more than the data size of the JPEG input buffer 21 in the data selector unit, the rescanning is performed without using the result of the scanning operation performed.
The JPEG calculation process is performed again. At this time, by setting the resolution of the read image to be reduced in the scaling processing unit 2084 of the scanner image processing unit 2080, the image data size to be subjected to the JPEG arithmetic processing in the re-scanning is reduced, and is output from the JPEG codec chip 4. JPE
The amount of G code data can be reduced, and at the same time, the output data transfer rate can be reduced.

That is, by setting the resolution in the scaling unit 2084 so that the output data transfer rate does not exceed the transfer rate of the image bus 2008, all the scanner read images can be read from the RAM 2002 on the system bus.
Can be stored.

The flow of the above operation configuration will be further described with reference to the flowchart of FIG. FIG. 11 is a flowchart illustrating the operation of the image processing unit according to the present embodiment.

When the scan operation is started by the copy start key on the operation unit (step S301), first, the copy operation is started.
Zero (Count = 0) is set as an initial value of unt (step S302). Then, the output signal "Irql" of the JPEG codec chip 4 is continuously monitored to determine whether or not Irql is "High" (step S30).
3). If Irql = "High", the variable Count is incremented (step S304).

The value of Count is compared with a predetermined value (step S305). If the value of Count is larger than the predetermined value,
As described above, this means that the JPEG input buffer 21 is full, and the scanned image data is not correctly transferred. For this reason, after the scanning operation is completed (step S306), the display unit 2013 of the operation unit 2012 displays “Reduce the resolution of the read image (600 dpi → 30
0dpi) Do rescanning? Is displayed and the user is provided with a touch panel-type selecting means capable of selecting whether or not to perform re-scanning (step S30).
7). Here, the predetermined value indicates a numerical value previously stored in a register in the image bus I / F controller 2021.

When the user instructs re-scanning (step S308), the resolution setting value of the resolution conversion processing in the scaling unit 2084 of the scanner image processing unit 2080 is reduced (step S309). In the present embodiment, since the resolution of the image read by the scanner is 600 dpi, it is set to reduce by 50% in order to convert the image to 300 dpi. After that, the operation shifts to the scanning operation after step S301 again, so that 300 dp
JPEG for image data reduced to i resolution
Compression processing will be performed.

On the other hand, if the value of Count is equal to or less than the predetermined value in step S305, the image data by the scanning operation has been normally transferred. Therefore, the processing of steps S302 to S305 is repeated until the scanning operation is completed (step S310). When the scanning operation is completed, J
The PEG compression process ends (steps S310, S31
1).

If it is instructed not to perform rescanning in step S308, the JPEG compression processing is terminated (step S311). In this case, correct image data is not transferred.

In the present embodiment, the case where PM-35 is used as the general-purpose JPEG codec chip 4 has been described. However, it is sufficient if the data from the scanner can be compressed in real time. It is needless to say that is not limited to this.

In this embodiment, the case where the output code data size becomes large as a result of the JPEG arithmetic processing and exceeds the transfer rate of the system bus has been described, but the common system bus in this embodiment is used. Some scanners, printers, network interfaces, memories, and image processing systems require the system bus to be used by multiple devices depending on the operation.
If a device having a higher priority than other JPEGs uses the system bus, the compression result of the JPEG codec chip 4 cannot be output on the system bus even if there is no problem with the transfer rate. It is clear that the present invention can be applied as a countermeasure in such a case. As described above, according to the present embodiment, in an image processing apparatus using a common system bus for a scanner, a printer, a network interface, a memory, and an image processing system, a system bus for JPEG-compressed code data is used. In order to cope with the problem of real-time transfer via the system, a structure for determining whether the transfer rate of the compressed data exceeds the maximum transfer rate of the system bus is provided. After the lower setting is performed, the operation of reading the same original from the scanner is performed again. As a result, when rescanning, JP
The data amount of the image data to be subjected to the EG compression is reduced, and the transfer rate of the code data amount after the compression processing can be reduced. Therefore, it is possible to prevent data from dropping out on the system during transfer, and to realize a configuration in which all data read from the scanner is transferred to the external memory and stored.

Even if the present invention is applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (for example, a copying machine, a facsimile, etc.) Device).

Further, an object of the present invention is to supply a storage medium (or a recording medium) in which a program code of software for realizing the functions of the above-described embodiments is recorded to a system or an apparatus, and a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention. Also,
When the computer executes the readout program code, not only the functions of the above-described embodiments are realized, but also the operating system (OS) running on the computer based on the instructions of the program code.
It goes without saying that a case where the functions of the above-described embodiments are implemented by performing some or all of the actual processing, and the processing performs the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written in a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0080]

As described above, according to the present invention,
Even if the amount of data generated by the compression processing is not determined, the data after the compression processing can be reliably transferred in real time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of an image processing apparatus according to an embodiment.

FIG. 2 is a diagram illustrating an overview of an image input / output device according to the embodiment.

FIG. 3 is a diagram illustrating an overview of an operation unit 2012.

FIG. 4 is a block diagram illustrating a configuration of an image compression unit 2040.

FIG. 5 is a block diagram illustrating a configuration of an image rotation processing unit 2030.

FIG. 6 is a block diagram illustrating a configuration of the image processing unit 1.

FIG. 7 is a block diagram illustrating a configuration of a scanner image processing unit 2080.

FIG. 8 is a block diagram illustrating a configuration of a printer image processing unit 2090.

FIG. 9 is a block diagram showing a configuration of a device I / F unit 2020.

FIG. 10 is a diagram for explaining communication between a data selector unit 2 and a JPEG processing unit 3 in the image processing unit 1.

FIG. 11 is a flowchart illustrating an operation of an image processing unit according to the present embodiment.

FIG. 12 is a diagram illustrating a state in which image data is transferred from discontinuous addresses.

FIG. 13 is a diagram illustrating rotation of an image in the order of reading data from a memory.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) H04N 7/24 H04N 7/13 Z 5C078 9A001 F term (reference) 5B047 AA01 BB02 CA08 CB25 EA01 5C059 KK34 MA00 PP01 RA01 RB01 RE18 SS12 TA53 TB20 TC15 TD12 UA02 5C072 AA01 BA20 EA05 TA04 TA07 UA08 5C073 AA05 BC02 BC05 CE02 5C076 AA22 BA03 BA04 BA05 BA09 BB06 5C078 BA57 CA34 DB04 9A001 CZ03 DD11 DZ06 HH27 HH28 JZ35

Claims (18)

[Claims] A compression unit configured to perform a compression process on image data scanned and input from a scanner to generate compressed image data; an output unit configured to output the compressed image data generated by the compression unit onto a bus; First determining means for determining whether the generation speed of the compressed image data in the compression means is higher than the output speed of the compressed image data in the output means; and if the generation speed exceeds the output speed by the first determination means. If it is determined, the resolution of the input image data is reduced and rescanning is performed by the scanner to generate low-resolution image data, and the low-resolution image data is processed by the compression unit, the output unit, and the determination unit. And a re-processing means for executing again. 2. The image processing apparatus according to claim 1, wherein said compression means is a JPEG of image data.
2. The image data processing device according to claim 1, wherein the image data is generated by performing compression. 3. The image data processing apparatus according to claim 1, wherein the output unit outputs the compressed image data to a memory device connected via the bus so as to store the compressed image data. 4. The output means buffers the compressed data input from the compression means in an output buffer and outputs the compressed image data onto the bus. The first determination means compresses the output buffer. 2. The image data according to claim 1, wherein a speed of generating the compressed image data in the compression unit is determined based on a storage state of the data as to whether the output speed of the compressed image data in the output unit is higher. Processing equipment. 5. The method according to claim 1, wherein, when the output buffer is full, the output speed of the compressed image data in the output unit is higher than the output speed of the compressed image data in the output unit. The image data processing apparatus according to claim 4, wherein: 6. The re-processing unit, when the first determining unit determines that the generation speed is higher than the output speed, determines whether or not to re-process the image data by lowering the resolution. Inquiry, when receiving an instruction to perform re-processing as a response to the inquiry, the image data is converted into low-resolution image data by resolution conversion, and the compression means, output means, 2. The image data processing apparatus according to claim 1, wherein the processing by the determination unit is executed again. 7. An input means for inputting image data from a scanner, buffering the image data in an input buffer, and then providing the image data to the compression means, and a processing speed of the compression means for inputting the image data to the input means. A second determination unit that determines whether the speed has fallen below a speed. The reprocessing unit determines that a processing speed of the compression unit is lower than an input speed of image data in the input unit in the second determination unit. 2. The processing according to claim 1, wherein, even when the determination is made, the processing by the compression unit, the output unit, and the determination unit is performed again on the low-resolution image data generated by converting the resolution of the image data. Image data processing device. 8. The method according to claim 1, wherein the second determination unit determines that the processing speed of the compression unit is lower than the input speed of the image data to the input unit when the input buffer becomes full. The image data processing device according to claim 7. 9. A compression step of performing compression processing on image data scanned and input from a scanner to generate compressed image data; an output step of outputting the compressed image data generated in the compression step to a bus; A first determining step of determining whether the generation speed of the compressed image data in the compression step is higher than the output speed of the compressed image data in the output step; and if the generation speed exceeds the output speed by the first determination step. If it is determined, the resolution of the input image data is reduced and rescanning is performed by the scanner to generate low-resolution image data, and the low-resolution image data is processed by the compression step, the output step, and the determination step. And a re-processing step for executing again. 10. The compression step includes a step of JPE of image data.
The image data processing method according to claim 9, wherein compressed image data is generated by performing G compression. 11. The image data processing method according to claim 9, wherein in the outputting step, the compressed image data is output to a memory device connected via the bus so as to store the compressed image data. 12. The output step includes buffering compressed data input from the compression step in an output buffer and outputting compressed image data onto the bus. The first determination step includes a step of compressing the output buffer. 10. The image data according to claim 9, wherein a speed of generating the compressed image data in the compression step is determined based on a data storage state as to whether the output speed of the compressed image data in the output step is higher. Processing method. 13. In the first determining step, when the output buffer becomes full, the generation speed of the compressed image data in the compression step is higher than the output speed of the compressed image data in the output step. 13. The image data processing method according to claim 12, wherein: 14. The re-processing step, when the first determining step determines that the generation speed exceeds the output speed, determines whether or not to re-process the image data by lowering the resolution. Inquiry, when receiving an instruction to perform re-processing as a response to the inquiry, the image data is converted into resolution to generate low-resolution image data, and the compression process, output process, 10. The image data processing method according to claim 9, wherein the processing in the determining step is executed again. 15. An input step of inputting image data from a scanner, buffering the input image data in an input buffer, and then providing the image data to the compression step, and inputting the image data to the input step. A second determining step of determining whether the speed has fallen below a speed. In the reprocessing step, the processing speed of the compression step is lower than the input speed of image data in the input step in the second determining step. 10. The method according to claim 9, wherein, even when the determination is made, the processing of the compression step, the output step, and the determination step is performed again on the low-resolution image data generated by converting the resolution of the image data. Image data processing method. 16. The method according to claim 16, wherein the second determining step determines that the processing speed of the compression step is lower than the input speed of the image data to the input step when the input buffer is full. The image data processing method according to claim 15, wherein 17. A storage medium for storing a control program for causing a computer to implement the image data processing method according to claim 9. 18. A storage medium for storing a control program executed by a computer, the control program performing a compression process on input image data to generate compressed image data; A code of an output step of outputting the compressed image data generated in the compression step onto a bus, and determining whether a generation speed of the compressed image data in the compression step exceeds an output speed of the compressed image data in the output step. A code for a first determination step; and if the first determination step determines that the generation speed exceeds the output speed, lowers the resolution of the input image data to generate low-resolution image data. Code of a re-processing step for re-executing the processing of the compression step, the output step, and the determination step on image data Storage medium, characterized in that it comprises a.