Analog image processing apparatuses were popular a few years ago. However, due to recent improvement of technology and demands for displaying color images, digital copying machines are widely used along with the conventional analog image processing apparatus.
Furthermore, copying machines dedicated for copying documents, facsimile machines dedicated for sending and receiving facsimile, scanners dedicated for scanning documents, printers dedicated for printing the documents were also know. However, recently, so-called digital compound machines have come into market. These digital compound machines have the functions of a copying machine, a facsimile machine, a scanner, a printer etc.
FIG. 18 is a block diagram that shows a hardware configuration of a conventional digital compound machine.
This digital compound machine has realizes respective functions by connecting a portion constituting a copying machine (a copying machine portion) formed of a digital read unit 2201 for reading image data, an image processing unit 2202 for processing the read image data, a video control section 2203 for performing various controls with respect to the image data, a series of each component in a write unit 2204 for outputting the processed image data onto a recording medium, a memory control unit 2205 for controlling holding of the image data and a memory module 2206 for holding the image data with units such as a facsimile control unit 2212 for additionally controlling facsimile transfer via a mother board 2211, a printer control unit 2213 for performing input control of image data transmitted from an externally connected personal computer, and a scanner control unit 2214 for performing input/output control of image data when being used as a scanner.
Accordingly, as for the copying machine portion for realizing a function as a copying machine, a series of operations of respective components of the read unit 2201, image processing unit 2202, video control unit 2203 and write unit 2204 are controlled by a system controller 2207, RAM 2208 and ROM 2209, and respective units of the facsimile control unit 2212, printer control unit 2213 and scanner control unit 2214 utilize a part of the series of operations established by the copying machine, to thereby realize functions of respective units.
In other words, the functions of the digital compound machine are realized by adding on the facsimile control unit 2212, printer control unit 2213 and scanner control unit 2214 to the copying machine portion which has been established as one system comprising the above-described series of components. This is based on a background that the processing speed is given priority (speed-up of the processing is contemplated) by constituting the above-described series of components of hardware such as ASIC (Application Specific Integrated Circuit).
Particularly, in Japanese Unexamined Patent Publication No. H5-20283, “Parallel data processing apparatus”, there is disclosed a technique related to a parallel data processing apparatus including a SIMD (Single Instruction Multiple Data stream) type parallel data processing apparatus and a MIMD (Multiple Instruction Multiple Data stream) type parallel data processing apparatus.
According to this parallel data processing apparatus, improvement of the processing speed is contemplated by performing the SIMD type parallel data processing with regard to regular processing (shading correction processing, scanner γ-correction processing, or the like), and performing the MIMD type parallel data processing with regard to irregular processing (error diffusion processing), via a switching control.
Therefore, it is possible to contemplate speed-up of the image processing by applying this parallel data processing apparatus to the read unit 2201, facsimile control unit 2212, printer control unit 2213, scanner control unit 2214 and image processing unit 2202.
However, in the conventional digital compound machine, since the copying machine portion has been established as one system, the respective units connected to the copying machine portion, such as the facsimile control unit 2212, the printer control unit 2213 and the scanner control unit 2214 must be built up as a system, respectively independently of the copying machine portion, in order to realize respective functions.
This means that it is necessary to constitute respective units as well as the image processing unit 2202 so as to include ASIC (not shown in FIG. 18) required for realizing the image processing function, respectively, causing a problem in that resources are not effectively utilized.
Moreover, even if overlapping of respective units is eliminated, and an efficient digital compound machine is formed so that image processing is performed by only the image processing unit, there is still a problem as described below. Consider, for example, a case where a read unit or a write unit of 400 dpi is to be upgraded to the one of 600 dpi. Improvement of the overall function of the apparatus cannot be easily effectuated only by replacing the unit under consideration.
Specifically, since the whole system is built so as to read/written at 400 dpi, it is necessary to redesign the image processing processor in the unit so that read/write at 600 dpi can be performed.
This is because when-image processing (error diffusion processing or the like) which is required to be performed referring to pixels around the target pixel is performed, the maximum pixel that can be handled by one processor is limited by a line memory in the image processing processor, while there is a demand for high-speed image processing using the SIMD type processor with parallel calculation.
Accordingly, there is a problem in that while most resources within the image processing processor are common, it is necessary to modify a chip due to a reason that the size of the internal memory capacity is relatively insufficient, and hence the development efficiency decreases, and the image processing processor cannot be effectively utilized.