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AssigneeCanon Kabushiki Kaisha
InventorHirokazu Tamura
Estimating the term…
An image processing apparatus comprises: means for performing color-reduction processing for a block; means for comparing color data of respective pixels in the block, thereby specifying a placement pattern of the color data included in the block; means for extracting, as first color data, color data corresponding to a pixel at a predefined position in the block, and further extracting color data other than the first color data included in the block; means for outputting the placement pattern specified, and the first color data and the color data other than the first color data, which are extracted; and means for controlling to execute color-reduction processing, for second image data formed from the first color data output, upon determining blocks each including a predetermined number of pixels as blocks to be processed, thereby further controlling to re-execute, for the block having undergone the color-reduction processing, processing by each means.
An image processing apparatus comprising:
An image processing apparatus which performs compression processing for image data upon determining blocks each including a predetermined number of pixels as blocks of interest to be processed, comprising:
An image processing method comprising:
An image processing method of performing compression processing for image data upon determining blocks each including a predetermined number of pixels as blocks of interest to be processed, characterized by comprising:
Dependencies are inferred from the claim text.
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Colour correction or control: reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut
Systems for the transmission or the storage of the colour picture signal; Details therefor, e.g. coding or decoding means therefor: using a…
Pictorial communication
About 5 years of term left · ends 19 Oct 2031 (estimated)
The present invention relates to a technique that compresses an image for each predetermined block, and that of performing image processing and restoration processing for the image compressed for each block.
Conventionally, to save the space on a memory/hard disk and to shorten the time taken to write data on it, not only a digital multifunctional peripheral but also image processing apparatuses such as a digital camera and a facsimile apparatus compress color image data, which allows for reduction in cost and a gain in speed. A JPEG scheme that uses discrete cosine transformation and a scheme that uses wavelet transformation are widely employed as color still image compression schemes. Encoding schemes of these kinds generally encode an image for each predetermined block (for example, for each unit of 8×8 or 16×16 pixels), and perform discrete cosine transformation, quantization, and entropy coding, thereby achieving high compression efficiency. In these schemes, variable-length coding for each block is adopted, so random access for referring to a small area is difficult. In this access, the code length is indeterminate depending on the type of image, so the position (memory address) of a block to be decoded is also indeterminate. This makes it necessary not only to determine this position in some way but also to perform decoding processing for each block. Also, discrete cosine transformation by JPEG normally requires 8×8 pixels as the block size. To perform discrete cosine transformation which uses this block unit at high speed, not only a high-speed arithmetic unit and dedicated hardware but also a buffer memory is necessary. An image compression technique (for example, Japanese Patent Laid-Open No. 2004-104621) which uses a small block size and a fixed compression ratio has been disclosed as an approach to solving these problems associated with the random access performance and the complexity of processing.
Also, with an increase in resolution, the number of pixels which require image processing is dramatically increasing, so the processing load is getting heavier. When the above-mentioned image compression is employed, processing of decoding compressed data becomes necessary to refer to and convert the pixel data having undergone this image compression. In other words, image processing cannot be performed for compressed data intact, so its decoding processing inevitably becomes necessary. This makes it necessary to process all pixels in high-resolution data for each pixel, thus prolonging the processing time. As techniques of compressing pixel data without encoding it, a known run length encoding scheme of storing pixel data and their run lengths, and a technique (for example, Japanese Patent Laid-Open No. 10-257488) of compressing pixel data by detecting an edge for each block and storing two colors of this edge have been disclosed.
FIG. 1 is a block diagram illustrating an example of the configuration of an image processing apparatus according to an embodiment;
FIG. 2 is a block diagram illustrating an example of the configuration of a controller shown in FIG. 1;
FIG. 3 is a view showing possible combinations of the pattern in each block;
Modes for carrying out the present invention will be described in detail below with reference to the accompanying drawings. A digital MFP (MultiFunction Peripheral) having a plurality of functions such as scanning, printing, and copying will be taken as an example of an image processing apparatus in embodiments of the present invention.
[First Embodiment]
As shown in FIG. 1, a controller 101 is connected to a scanner 102 serving as an image input device, and a printer 103 serving as an image output device. The controller 101 is also connected to a network 104 such as a LAN or a public line (WAN) to input/output image information or device information and perform image rasterization of PDL data. A CPU 105 serves as a processor which controls the overall MFP in accordance with a program stored in an HDD storage unit 107. A memory 106 serves as a system working memory for operating the CPU 105, and also serves as an image memory for temporarily storing image data. The HDD storage unit 107 serves as a hard disk drive and stores, for example, system software, a program, and image data.