JPH08289138A - Image reduction device - Google Patents

Abstract

PURPOSE: To provide an image reduction device in which increase in a memory amount attended with increase in the reduction rate is prevented with an inexpensive and small scale configuration. CONSTITUTION: In the case of reducing an input image to 1/2, after image data of a 1st line are stored in a line buffer 103, 2nd line image data are fetched and inputted to an interleave processing section 102. Through the input of the 2nd line data, the line buffer 103 is shifted and the image data of the 1st line are extracted and fed back to the interleave processing section 102. The interleave processing section 102 applies simple interleave processing of OR processing with respect to the input image data and the feedback data and the result is outputted to the line buffer 103. Data by one line being 1/2 reduction data are stored in the line buffer 103 and shifted by the input of a succeeding 3rd line of data to obtain output data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reducing device for reducing an input image to 1 / N.

[0002]

2. Description of the Related Art An image reducing apparatus for reducing an input image to 1 / N is as follows. The area of the output screen in the display device is reduced.

B. As a data processing unit such as FAX / Printer / Scanner, the resolution of input image data and the resolution of IOT (information output device) are matched.

It is widely used for such purposes.

As image reduction processing in this type of image reduction apparatus, simple thinning-out processing in which any one of the noted N lines is selected as an output image and logical OR (OR) of all the N lines are performed. The OR process is generally used as an output image.

A conventional image reducing device of this type will be briefly described. FIG. 7 is a functional block diagram showing a conceptual configuration of a conventional image reducing apparatus of this type, which includes a line buffer 710, a thinning processing unit 720, and a clock processing unit 730. Here, the line buffer 710 is a storage unit for storing one line of the input image, and in this example, in particular, two line buffers 1 and 2 are used to reduce the image in size to 1/2. Is disclosed.

The input image is always started to be stored in the line buffer 2. The input image for one line is stored in the line buffer 2. At the same time, the previously stored data is shifted (transferred) to the line buffer 1. Works like. As a result, in the apparatus, the input images for two lines are sequentially stored in the line buffers 1 and 2.

The thinning-out processing unit 720 performs thinning-out processing or OR-processing thinning-out processing on the output data from the line buffers 1 and 2. Then, the output of the thinning processing unit 720 becomes an image output. The clock processing unit 730 controls the operation timing of the thinning processing unit 720 according to the image clock input.

Next, 1 of the input image in this conventional apparatus is used.
The 1/2 reduction operation will be described. First, from image input 1
When the data of the line is input, the data of the first line is stored in the line buffer 2. Subsequently, at the same time as the data of the second line is input from the image input, the data already stored in the line buffer 2 is shifted to the line buffer 1. As a result, the line buffer 1 stores the data of the first line, and the line buffer 2 stores the data of the second line.

Further, at the same time that the data of the third line is input from the image input, the data of the line buffers 1 and 2 are input to the thinning processing section 720. Thinning processing unit 720
Performs simple thinning-out processing or OR processing on the above two lines of data, and outputs the processing result as an image output.

Similarly, the thinning-out processing unit 720 is performed for every two adjacent odd-numbered lines and even-numbered lines.
Then, the thinning-out processing is performed as described above, and finally, reduced image data in which the number of lines is thinned to 1/2 is generated.

As a concrete example of this type of conventional apparatus, for example, in Japanese Patent Application Laid-Open No. 3-11476 (Japanese Patent Application No. 1-145478), simple thinning processing and OR processing are used together, and according to the nature of the image,
A pixel density conversion device that selectively executes one of the above processes is disclosed.

This pixel density conversion device stores image data of each line of the first line, the second line, and the third line in the line buffers 1, 2, and 3, respectively, and then inputs these data and the next. The image data of the fourth line is transferred to the logical sum processing unit or the thinning processing unit for reduction processing, and one of the processing results is selected by the multiplexer and output, whereby the main scanning direction and the sub scanning are performed. The image output is reduced to 1/4 in the direction.

According to such a configuration of the conventional apparatus, a line buffer for N lines is required to perform thinning processing for N lines, and the number of line buffers increases as the reduction ratio increases. It was Therefore, if the reduction rate increases, the cost of the device rises due to the need to increase the number of line buffers, and the device shape must be increased with the increase in the mounting area of these buffer memories.

[0015]

As described above, in the above-described conventional image reducing apparatus, in order to perform the 1 / N reduction processing, a memory for storing at least N lines of data is required. Since a large number of memories are required as the reduction rate increases, there is a problem in that the cost of the device and the size of the device must be increased.

The present invention solves the above problems and does not require an increase in memory usage in accordance with an increase in the reduction ratio, and maintains a low cost and downsizing of the device while maintaining a highly accurate reduced image. An object is to provide an image reduction device that can generate data.

[0017]

SUMMARY OF THE INVENTION The present invention is based on N
In an image reducing apparatus for reducing the input image to 1 / N by referring to line data, a single line buffer (line buffer 103 in FIG. 1) for storing image data for one line, and an input image Thinning processing means for performing thinning processing on data and feedback data from the line buffer and storing the processing result in the line buffer (similarly, thinning processing section 102), and thinning processing means for storing data in the line buffer. And the feedback count is (N-1)
Feedback control means (also referred to as a buffer control unit 104) that outputs the stored data in the line buffer as reduced image data each time the number of times is reached.

[0018]

In the present invention, the N lines of interest are not expanded and reduced on the N line buffers at a time, but
A line buffer and means for feeding back the data in the buffer to the thinning processing means are added, and the above N
By repeating simple thinning processing or OR processing between adjacent lines with respect to the input of a line, the processing results are sequentially updated on the line buffer, and the N-1th processing result is output as an image. As a result, the input image is reduced to 1 / N by referring to the data of N lines. According to this processing, even if the 1 / N reduction processing is performed, it is sufficient to have one memory for storing the data for one line, and the memory usage amount increases corresponding to the increase in the reduction ratio. It is possible to realize a small and inexpensive device configuration without any need.

[0019]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing a functional configuration of an image reducing apparatus according to an embodiment of the present invention, which includes an image selecting unit 101, a thinning processing unit 102, and a line buffer 10.
3, a buffer control unit 104, a counter 105, and a clock control unit 106.

The image selecting means 101 automatically identifies the characteristics of the input image or manually (fixed designation by the user), and a thinning-out processing unit 102 described later.
Thinning-out processing or logical sum processing (OR processing) in
It is a means for selecting one of the two. Here, the characteristics of the input image refer to the type of the image (text / photo / picture) and the brightness of the image. As a general method of automatically identifying the input image, a method of identifying any pixel from a limited range of the input image and comparing it with a pattern prepared in advance can be considered.

The thinning-out processing unit 102 receives the input image data given through the image selecting means and the line buffer 103.
This is means for performing image reduction processing with the data fed back from, and is realized by a simple thinning processing circuit or an OR processing circuit. The output of the thinning processing unit 102 is input to and stored in the line buffer 103. The line buffer 103 is a storage unit for storing one line of the input image. It has a FIFO structure, and when one pixel is input from the image input, the data is shifted by one pixel to the image output side (the data is pushed out). The buffer control unit 104 controls the operation timing of the thinning processing unit 102 and the shift operation of the line buffer 103 based on the synchronization signal from the clock control unit 106 and the signal from the counter 105.
When performing 1 / N reduction, the counter 105 sequentially counts a value of 0 to N−1 as a counter value, and is used to recognize which line in the reduction process the current input image is. .

The general operation of the image reduction processing in the image reduction apparatus 10 of the present invention will be described below. FIG. 2 is a flowchart showing an example of the 1 / N reduction operation of an image in the image reducing apparatus 10 when the image selecting unit 101 selects the “simple thinning process”.

First, the count value of the counter 105 is reset to "0" (step 201), and in this state,
The image data of the first line is input from the image input, and is taken into the thinning processing unit 102 (step 202). By the input of this image data, the line buffer 103 is sequentially shifted to the right (step 203), but here, the buffer control unit 104 recognizes that the count value of the counter 105 is “0” (step 204 YES). The shift output data from the line buffer 103 is output as reduced image data (step 205). If the buffer control unit 104 recognizes that the count value is “0” as described above, it inputs the input image data as it is to the line buffer 103 (step 20).
6).

After the input of the input image data to the line buffer 103 is completed, the count value of the counter 105 is increased to "+".
1 ”(step 209). Next, the buffer control unit 104 determines whether the count value of the counter 105 has reached (N-1). This is a process for confirming whether or not the N line is referred to in the 1 / N reduction process of this example.

Here, when the count value of the counter 105 has not reached (N-1) (step 210N).
O), further, the image data of the next line is input from the image input, and this is taken into the thinning processing unit 102 (step 202). By inputting this image data, the line buffer 103 is sequentially shifted to the right (step 203). Here, the buffer control unit 104 recognizes from the count value of the counter 105 = “1” that the count value is not “0” (step 204 NO), and thins out the shift data output from the line buffer 103. 10
It is fed back to 2 (step 207). Upon completion of this feedback, the buffer control unit 104 continues to feed back the newly input input image data of the second line and the feedback from the line buffer 103 in accordance with the designation of the “simple thinning process” performed earlier.
Either one of the input image data of the line is selected and input to the line buffer 103 (step 20).
8). After the input of the input image data to the line buffer 103 is completed, the counter 105 increments the count value by "+1" (step 209).

After that, the count value of the counter is (N-
Steps 202 → 203 → 204 → 2 until 1) is reached
The process of 07 → 208 → 209 is continued. Then, when the count value of the counter reaches (N-1) during this period (YES in step 210), the process proceeds to the reduction process of the next N lines. Specifically, if the count value of the counter is (N
-1) is reached (YES in step 210), it is determined whether the processing for one screen is completed (step 21).
1) While it is not ended (NO in step 211), the process returns to the process after step 202 where the count value is set to “0”, and the thinning process for the next N lines is continued until the process for one screen is completed. By the above processing, the simple thinning processing result is sequentially updated on one line buffer for the N line of interest, and the result data is taken out as an image output for every N line, thereby reducing the 1 / N reduced image. You can get the data.

Next, FIG. 3 is a flow chart showing an example of the 1 / N reduction operation of the image when the "OR processing" is selected by the image selection means 101 in the image reduction apparatus 10.

First, the count value of the counter 105 is reset to "0" (step 301), and in this state,
The image data of the first line is input from the image input, and is taken into the thinning processing unit 102 (step 302). By the input of this image data, the line buffer 103 is sequentially shifted to the right (step 303). Here, the buffer control unit 104 recognizes that the count value of the counter 105 is "0" (step 304 YES). The shift output data from the line buffer 103 is output as reduced image data (step 305). If the buffer control unit 104 recognizes that the count value is “0” as described above, it inputs the input image data as it is to the line buffer 103 (step 30).
6).

After the input of the input image data to the line buffer 103 is completed, the count value of the counter 105 is set to "+".
1 ”(step 309). Next, the buffer control unit 104 determines whether the count value of the counter 105 has reached (N-1). Here, when the count value of the counter 105 has not reached (N-1) (step 3
10 NO), and further, the image data of the next line is input from the image input, and this is taken into the thinning-out processing unit 102 (step 302). By inputting this image data, the line buffer 103 is sequentially shifted to the right (step 30).
3).

Here, the buffer control unit 104 recognizes that the count value is not "0" by the count value of the counter 105 = "1" (step 304 NO),
The shift data output from the line buffer 103 is fed back to the thinning processing unit 102 (step 307). Upon completion of this feedback, the buffer control unit 104 continues to input the newly input image data of the second line and the first line fed back from the line buffer 103 according to the designation of the “OR processing” previously performed. The data resulting from the OR processing with the input image data of is input to the line buffer 103 (step 308). After the input of the input image data to the line buffer 103 is completed, the counter 105 increments the count value by "+1" (step 309).

After that, the count value of the counter is (N-
Steps 302 → 303 → 304 → 3 until 1) is reached
The process of 07 → 308 → 309 is continued. Then, when the count value of the counter reaches (N-1) during this period (YES in step 310), the process proceeds to the reduction processing of the next N lines. Specifically, if the count value of the counter is (N
-1) is reached (YES in step 310), it is determined whether the processing for one screen is completed (step 31).
1) While it is not ended (NO in step 311), the process returns to step 302 and thereafter in which the count value is set to “0”, and the thinning processing for the next N lines is continued until the processing for one screen is completed. By the above-described processing, for the N lines of interest, the result data is taken out as an image output for each N line while sequentially updating the OR processing result on one line buffer, and the 1 / N reduced image data is obtained. Can be obtained.

Next, as a specific example of the reduction processing by the image reducing apparatus 10 of the present invention, a case where the input image is reduced to 1/2 will be described with reference to FIGS. In the following description, the image selection means 101
When "Simple decimation process" is selected and "OR process"
Will be explained separately for the case where is selected. These selection controls can be performed by the image selection means 101 by automatically identifying the characteristics of the input image data, and can be performed based on the identification result, or can be performed based on fixed designation by a user's manual operation. As described above.

1. When "Simple thinning process" is selected by the image selection means 101 1-1. The count value of the counter 105 is reset to "0".

1-2. The image data of the first line is input from the image input. This input image data is the image selection means 1
It is input to the thinning processing unit 102 through 01.

1-3. By the input of the image data, the line buffer 103 is shifted, and the output data accompanying this shift is obtained as an image output. [In this processing, the first line of the image output is a dummy output, and the second and subsequent lines are:
As shown in FIG. 6, the normal output is obtained]. At the same time, the output data is fed back and input as feedback data to the thinning processing unit 102.

1-4. The buffer control unit 104 recognizes the count value (= 0) of the counter 105, and when the recognition result is obtained, outputs the input image data as it is to the line buffer 103. At this time, the feedback data is ignored.

1-5. The image data for one line is stored in the line buffer 103. FIG. 4 shows a data processing image in this processing step. In the state of the count value (= 0), the line buffer 103 stores the input image data An to A1 of the first line.

1-6. The count value of the counter 105 is “+
1 ”is added and the count value is set to“ 1 ”.

1-7. The image data of the second line is input from the image input. This input image data is input to the thinning processing unit 102 through the image selection unit 101.

1-8. The line buffer 103 shifts,
Output data accompanying this is fed back and input to the thinning-out processing unit 102.

1-9. The buffer control unit 104 recognizes the count value (= 1) of the counter 105, and when the recognition result is obtained, the buffer control unit 104 thins out the input image data and the feedback data. In this example, since the “simple thinning process” is selected by the image selection unit 101, the buffer control unit 104 selects either the input image data or the feedback data and outputs it to the line buffer 103. To do.

1-10. The line buffer 103 stores data for one line thinned out by the simple thinning processing. FIG. 5 shows an image of data processing in the processing steps 1-6 and after. The count value is set to (= 1), and the input image data An to A1 of the first line is input from the line buffer 103. It is given to the thinning-out processing unit 102 as feedback data, and after being thinned out between the input image data Bn to B1 of the first line, the processing result data Dn to D1 are stored in the line buffer 103 again. Is represented. In this example, in the thinning processing unit 102,
As a result of the simple thinning processing, the input image data An to A1 of the first line or the input image data B of the second line
The data of any one of the lines n to B1 is obtained as the image outputs Dn to D1.

1-11. Return to 1-1. After that, the processing from 1-2 to 1-10 is repeatedly performed on the image data from the third line onward to the final line. FIG. 6 shows a data processing image at the time of inputting the third line in the processing step. The count value is set to (= 0), and the input image data Cn to C1 of the third line are stored in the line buffer. As it is loaded into the line buffer 103, the simple thinning processing result data Dn to D1 between the first line data An to A1 and the second line data Bn to B1 already stored in the line buffer 103 are displayed in the image. It is shown as being pushed out as output.

2. By the image selection means 101, "OR
When "Process" is selected 2-1. The count value of the counter 105 is reset to "0".

2-2. The image data of the first line is input from the image input. This input image data is the image selection means 1
It is input to the thinning processing unit 102 through 01.

2-3. By the input of the image data, the line buffer 103 is shifted, and the output data accompanying this shift is obtained as an image output. [In this processing, the first line of the image output is a dummy output, and the second and subsequent lines are:
As shown in FIG. 5, a normal output is obtained]. At the same time, the output data is fed back and input as feedback data to the thinning processing unit 102.

2-4. The buffer control unit 104 recognizes the count value (= 0) of the counter 105, and when the recognition result is obtained, outputs the input image data as it is to the line buffer 103. At this time, the feedback data is ignored.

2-5. The image data for one line is stored in the line buffer 103. FIG. 4 shows a data processing image in this processing step. In the state of the count value (= 0), the line buffer 103 stores the input image data An to A1 of the first line.

2-6. The count value of the counter 105 is “+
1 ”is added and the count value is set to“ 1 ”.

2-7. The image data of the second line is input from the image input. This input image data is input to the thinning processing unit 102 through the image selection unit 101.

2-8. The line buffer 103 shifts,
Output data accompanying this is fed back and input to the thinning-out processing unit 102.

2-9. The buffer control unit 104 recognizes the count value (= 1) of the counter 105, and when the recognition result is obtained, the buffer control unit 104 thins out the input image data and the feedback data. In this example, since the “OR processing” is selected by the image selection means 101, the buffer control unit 104 performs the OR processing of the input image data and the feedback data, and outputs the processing result to the line buffer 103. Output.

2-10. The line buffer 103 stores data for one line thinned out by the OR processing. FIG. 5 shows an image of data processing in the processing steps 1-6 and after. The count value is set to (= 1)
The input image data An to A1 of the line are fed to the thinning processing unit 102 as feedback data, and after the thinning processing is performed between the input image data Bn to B1 of the first line, the processing result data Dn to D1 are output to the line. The state of being stored again in the buffer 103 is shown. In this example, as a result of the OR processing in the thinning processing unit 102, the input image data A of the first line is obtained.
Data corresponding to the logical sum of n to A1 and the input image data Bn to B1 of the second line are obtained as image outputs Dn to D1.

2-11. Return to 2-1. After that, the process from 2-2 to 2-10 is repeated for the image data from the third line to the last line. FIG. 6 shows a data processing image at the time of inputting the third line in the processing step. The count value is set to (= 0), and the input image data Cn to C1 of the third line are stored in the line buffer. O of the first line data An to A1 and the second line data Bn to B1 which have already been stored in the line buffer 103 as they are fetched by 103.
It can be seen that the R processing result data Dn to D1 are pushed out as an image output.

[0055]

As described above, according to the present invention,
A line buffer for one line and a control means for feeding back the data in the line buffer to the thinning processing section are provided, and while performing thinning processing between adjacent lines on the input of N lines, on one line buffer Since the thinning processing result is sequentially updated and the N-1th processing result held in the line buffer is output as an image, 1 / N reduction processing is performed for one line. If you have a memory to store the data,
It is possible to avoid an increase in the amount of memory used due to an increase in the reduction rate, and it is possible to perform high-magnification and high-performance reduction processing while maintaining the cost reduction and downsizing of the device.

[Brief description of drawings]

FIG. 1 is a functional configuration block diagram of an image reduction device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an example of 1 / N image reduction processing when simple thinning processing is selected in the image reduction apparatus according to the present invention.

FIG. 3 is a flowchart showing an example of 1 / N image reduction processing when OR processing is selected in the image reduction apparatus according to the present invention.

FIG. 4 is a diagram showing a data string in a line buffer when inputting image data of a first line when the image reduction device according to the present invention reduces the image size by 1/2.

FIG. 5 is a diagram showing a data sequence of a line buffer when image data of a second line is input when the image reduction device according to the present invention reduces the image size to 1/2.

FIG. 6 is a diagram showing a data sequence of a line buffer when image data of a third line is input when the image reduction device according to the present invention reduces the image size to 1/2.

FIG. 7 is a functional block diagram showing a conceptual configuration of a conventional image reduction device.

[Explanation of symbols]

10 image reduction device, 101 image selection means, 102
Thinning processing unit, 103 line buffer, 104 buffer control unit, 105 counter, 106 clock control unit

Claims (2)

[Claims] 1. An image reducing apparatus for reducing the input image to 1 / N by referring to N-line data of the input image, wherein a single line buffer for storing image data of 1 line, and an input image Decimation processing means for performing decimation processing between data and feedback data from the line buffer and storing the processing result in the line buffer; and feeding back the data stored in the line buffer to the decimation processing means, and the number of times of feedback. (N-1) times, the feedback control means outputs the data stored in the line buffer as reduced image data. 2. The thinning processing means is configured to be capable of executing a simple thinning processing or a logical sum processing as the thinning processing, and an image identifying means for automatically identifying a characteristic of the input image data, and the image identifying. 2. The image reducing apparatus according to claim 1, further comprising a selecting means for selecting either simple thinning processing or logical sum processing in the thinning processing means in accordance with an identification result of the means or a manual selection operation. .