JPH0253989B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a decoder having a data extraction function that allows decoding of only a specific portion of data from encoded data.

Conventionally, for example, when reading coded data stored in an image memory and cutting out only a part of the image to display on a display or record on a plotter, a decoder reads all the coded data at once. After decoding, a separately provided data extraction circuit is used to extract the specific part of the data that is needed, which increases the circuit scale and increases the need for data decoding in unnecessary parts. Since the processing is performed, the data processing becomes a waste of time.

The present invention has been made in consideration of these points, and provides a decoder that can simultaneously cut out a specific portion of data when decoding encoded data. .

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 1 shows an example of the basic configuration of a decoder according to the present invention, in which a coded signal sent from an external image memory etc. and coded by the modified Hoffman method is synchronized with clock CLK1. and the line sync signal (EOL) it contains
A decoding circuit 1 detects terminating code (TC), detects data code, and changes the pixel information from white to black level using the EOL detection signal a and changes the pixel information from white to black level using the TC detection signal b. The data code is detected by the pixel information control circuit 2 and the decoding circuit 1, which inverts the pixel and provides the decoding circuit 1 with a state signal c of the white and black levels of the pixel corresponding to the code to be decoded. The run length is set according to the decoded data d to be decoded (consisting of run length information and identification information of the terminating code TC/makeup code MC) given by . (If it is a MC, a value multiplied by 64 is set.) The set value is counted down according to the clock CLK2, and when the content reaches zero, the output e is given to the clock control circuit 4 and the value of the clock CLK2 is A run generation counter 3 that stops sending out and a clock that receives white or black pixel information f output from the pixel information control circuit 2 from a clock control circuit 4.
The decoded signal is read in synchronization with CLK2 and temporarily accumulated, and the accumulated decoded signal is read in synchronization with clock CLK2.
3 and an output buffer circuit 5 which outputs data to an external display, plotter, etc. in synchronization with 3.

However, in a decoder configured in this way,
The encoded signal applied from the outside is decoded for each line according to the run length of white or black pixels.

In such a decoder, particularly in the present invention, as shown in FIG. 2, the decoder is constructed by incorporating a data extraction section into the decoding section.
That is, the data extraction section includes a decoding information (run length information) control circuit 6 provided between the decoding circuit 1 and the run generation counter 3 in the decoding section, and the EDL output from the decoding circuit 1. It is constituted by two EOL counters 7 and 8 that provide control commands to the decoding information control circuit 6 at appropriate timings while counting the detection signal a.

EOL counter 7 in this data extraction section
As shown in FIG. 3, when data of a specific image portion B is extracted from the original image A, an arbitrary value is determined according to the distance l1 from the starting edge of the original image A to the starting edge y1 of the specific image portion B. The value of is preset via a system control device (not shown), the EOL detection signal a outputted from the decoding circuit 1 is read, the preset value is counted down, and when the content reaches zero, the output g is sent to the decoding information control circuit. Give to 6. The EOL counter 8 also measures the width l2 in the sub-scanning direction from the starting edge y1 to the ending edge y2 of the specific image portion 8.
An arbitrary value corresponding to the EOL counter 8 is preset via a system control device (not shown), etc.
When the content becomes zero, the EOL detection signal a output from the decoding circuit 1 is read in response to the start signal h given from the decoding information control circuit 6, the preset value is counted down, and the preset value is counted down. Then, the output i is given to the decoding information control circuit 6. Now, for example, when the distance from the starting edge of original image A to the starting edge y1 of specific image part B is l1mm, and the distance between the starting edge y1 and ending edge y2 of that specific image part B is l2mm, and the original image A is read, When the sub-scanning density is 8 lines/mm, the EOL counter 7 has 8 lines/mm.
The value ×l1 is preset, and the EOL counter 8 is preset to the value 8×l2. Further, the decoding information control circuit 6 controls the decoding data d even if the decoding data d is sent from the decoding circuit 1 until the control command g is issued from the EOL counter 7.
is immediately cut off without giving it to the run generation counter 3, and only when the control command g is given from the EOL counter 7, the decoded data d is sent to the run generation counter 3.
to be sent to. The decoding information control circuit 6 receives the control command g
At the same time, a start signal h is given to the EOL counter 8 to start its counting operation, and when the count reaches zero, a run of decoded data d is generated again in response to a control command i issued from the EOL counter 8. Sending to counter 3 is stopped immediately. Therefore, the decoded data d output from the decoding circuit 1 is applied to the run generation counter 3 while the EOL counter 8 is counting until it reaches its preset value.

Therefore, in the decoder according to the present invention configured as described above, the positions of the starting edge y1 and the ending edge y2 of the specific image portion B, which is the target of data extraction in the original image A, can be arbitrarily specified using input means such as a keyboard. If this is done, the EDL counters 7 and 8 are preset to predetermined values via the system control device, etc., and the decoded data d of only the specific image portion B is set by the decoding information control circuit 6 in accordance with the output of each EOL counter 7 and 8. (run length information) is cut out and processed for decoding, and as a result, only the decoded data of the specific image portion B is stored in the output buffer circuit 5.

In the above explanation, we have described the case where a coded signal encoded by the Modified-Hoffman method is decoded.
It goes without saying that the present invention can be similarly implemented even when decoding signals encoded by other encoding methods using encoding systems including EDL. Further, as in the above embodiment, the EOL counter 8 is preset to a value corresponding to the width l2 of the specific image portion B,
Instead of starting the counting operation in response to the output of the EDL counter 7, the EDL counter 8 is preset to a value corresponding to the distance l1+l2 from the starting edge of the original image A to the ending edge y2 of the specific image portion B. , the counting operation is performed by EDL counter 7.
At the same time, the decoding information control circuit 6 starts
The decoded data d from when the output of the EOL counter 7 is generated until the output of the EOL counter 8 is generated may be controlled so as to be valid and supplied to the run generation counter 3.

As described above, in the decoder according to the present invention, EOL
A signal encoded by a coding system including
In a device that decodes each line while detecting EOL, an arbitrary value is preset according to the starting edge position of a specific image part from which data is to be extracted in the original image, and the EOL detection signal is counted. A first counter that generates an output when it reaches a preset value, and a first counter that is also preset to an arbitrary value depending on the end position of a specific image section, counts the EOL detection signal, and generates an output when it reaches the preset value. and a decoding information control circuit that determines validity or invalidity of image information to be decoded according to the outputs of the first and second counters, This system is designed to decode only the image information that has been validated by the control circuit, and it is also possible to simultaneously cut out the data of a specific image part at the time of decoding, and also to cut out unnecessary image parts. Since data is not decoded, it has the excellent advantage of effectively speeding up the processing.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a basic configuration example of a decoder according to the present invention, Fig. 2 is a block diagram showing an example of the present invention, and Fig. 3 is a target of data extraction in an original image. FIG. 3 is a diagram showing a specific image portion. 1...Decoding circuit, 2...Image information control circuit, 3...
Run generation counter, 4... Clock control circuit, 5...
output buffer circuit, 6... decoding information control circuit, 7,
8...EDL counter.

Claims (1)

[Claims] 1 In a decoder that decodes a signal encoded using a coding system including a line synchronization signal line by line while detecting the line synchronization signal, a specific image from which data is to be extracted from the original image is used. A first counter is preset to an arbitrary value according to the starting end position of a specific image section, and generates an output when the EOL detection signal is counted and reaches the preset value. a second counter that counts the EOL detection signal and produces an output when it reaches the preset value;
and a decoding information control circuit that determines whether the image information to be decoded is valid or invalid according to the output of each second counter, and only the image information that is validated by the decoding information control circuit is provided. A decoder characterized in that it performs decoding.