JP3604708B2 - Image output device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image output device, and more particularly, to an image output device having a unit for storing image data and a unit for performing image processing such as resolution conversion and primary conversion of image data.
[0002]
[Prior art]
Conventionally, in this type of image output device, when the resolution of input image data is different from the resolution of an image output device such as a printer, after converting the resolution, the image data is stored in a page memory and then output.
[0003]
FIG. 2 shows a configuration block diagram of an example of this type of conventional image output apparatus. When image data is input from an input terminal 301 from a host computer or the like (not shown) and the resolution of the input image data is different from the resolution of the printer engine 306 in the resolution conversion circuit 302, the input image data is reduced or enlarged to The resolution of the engine 306 was made to match. That is, if the resolution of the input image data exceeds the resolution of the printer engine 306, the image data is reduced. Conversely, if the resolution of the input image data is smaller than the resolution of the printer engine, the image data is expanded. . The resolution-converted image data is compressed in a compression circuit 303 by a coding method suitable for compressing the image data, for example, an orthogonal transform such as DCT (discrete cosine transform), or a known coding method such as block coding. Are stored in the memory 304.
[0004]
Next, when the printer engine 306 is started, the image data stored in the memory 304 is returned to the data before being compressed by the decompression circuit 305, and is sent to the printer engine 306 in accordance with the synchronization signal of the printer engine 306. It was output and a printout was being executed.
[0005]
[Problems to be solved by the invention]
However, in the above-described conventional image output device, when the resolution of the input image data is smaller than the resolution of the image output device, the number of pixels of the input image data increases due to the resolution conversion. And the use efficiency of the memory deteriorates.
[0006]
The present invention has been made in view of the above-described problems of the related art, and performs a compression process without increasing the number of pixels of input image data at the time of the above-described resolution conversion. It is an object of the present invention to provide an image output apparatus that can effectively utilize the image output.
[0007]
[Means for Solving the Problems]
The present invention has achieved the above object by the following technical configuration.
[0008]
(1) and the primary conversion means for performing a linear transformation processing on the image data, and compression means for compressing the converted data by the primary conversion means, a memory means for storing the data compressed by the compression means, the storage Expansion means for expanding data stored in the means, and expansion means for performing expansion processing on the data expanded by the expansion means, wherein the primary conversion means converts the image data requiring reduction processing into image data that requires reduction processing. On the other hand, a primary conversion process including a reduction process is performed, and a primary conversion process other than a scaling process is performed on image data that requires an enlargement process. An image output apparatus that performs enlargement processing on image data that has not been subjected to the processing and needs the enlargement processing .
[0009]
[Action]
According to the above-described configuration of the present invention, when performing the primary conversion, the primary conversion process is separated into an enlarged component and a component other than the enlarged component, and the primary conversion process using the component other than the enlarged component is stored in the memory. By performing the primary conversion process (enlargement process) using the enlarged component after storing the image data in the memory, the number of pixels stored in the memory is reduced, and the memory can be used effectively.
[0010]
【Example】
Hereinafter, the present invention will be described based on examples;
(Example 1)
FIG. 1 shows a block diagram (corresponding to FIG. 2 of the conventional example) of a first embodiment of an image output apparatus according to the present invention. In the figure, 101 is an input terminal from a host computer or the like, 108 is a primary conversion circuit, 103 is an image data compression circuit, 104 is a memory, 105 is an image data expansion circuit, 109 is an enlargement circuit, and 107 is a printer engine.
[0011]
The first embodiment is an example applied to the primary conversion processing of the input image data. When performing the primary conversion processing on the image data input from the input terminal 101, the primary conversion circuit 108 And processing other than the enlarged component is performed on the input image data. The input image data that has been subjected to the primary conversion processing other than the enlarged component is compressed by the compression circuit 103 and stored in the memory 104. The compression circuit 103 compresses input image data according to a known encoding method such as JPEG (International Standardization Working Group) and stores it in the memory 104.
[0012]
Next, when the printer engine 107 is started, the image data stored in the memory 104 is expanded to data before compression by the expansion circuit 105 and output to the resolution expansion circuit 106. The enlargement circuit 106 executes the processing of the enlarged component, which is not executed by the primary conversion circuit 108, on the decompressed image data and outputs it to the printer engine 107 to execute printout. .
[0013]
As described above, in the present embodiment, the primary conversion process is separated into two components, an enlarged component and a component other than the enlarged component, and the processes other than the enlarged component are performed in the previous stage of the image data compression circuit 103, and the process of the enlarged component is performed. By performing the resolution conversion in the subsequent stage of the image data decompression circuit 105, the number of pixels stored in the memory 104 can be reduced without deterioration in image quality. As a result, when the memory occupancy is the same, loss due to compression can be reduced, and higher image quality can be expected. When the same compression ratio is used, the memory occupancy can be reduced, and the surplus memory can be used for another purpose.
[0014]
【The invention's effect】
As described above, according to the present invention, the primary conversion process is separated into two components, an enlarged component and a component other than the enlarged component, and the process other than the enlarged component is performed at a stage prior to the image data compression circuit. Is subjected to resolution conversion at the subsequent stage of the image data decompression circuit, so that the number of pixels stored in the storage means can be reduced without deterioration in image quality. As a result, when the same memory occupancy is used, loss due to compression can be reduced, and high image quality can be expected. When the same compression ratio is used, the memory occupancy can be reduced, and the surplus memory can be used for another purpose.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram of a first embodiment of the present invention. FIG. 2 is a configuration block diagram of an example of a conventional image output device.
103 image data compression circuit 104 memory 105 image data decompression circuits 107 of the printer engine 108 input image data primary conversion circuit 109 image data expanding circuit

Claims (1)

A primary conversion means for performing a linear transformation processing on the image data,
Compression means for compressing the data converted by the primary conversion means,
Storage means for storing data compressed by the compression means,
Decompression means for decompressing data stored in the storage means,
Enlargement means for performing enlargement processing on the data expanded by the expansion means,
Has,
The primary conversion unit performs a primary conversion process including a reduction process on image data that requires a reduction process, and performs a primary conversion process other than a scaling process on image data that requires an enlargement process. Run,
The image output device according to claim 1, wherein the enlargement unit performs enlargement processing on the image data requiring the enlargement process, which has not been subjected to the enlargement process by the primary conversion unit .

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