JPS60261253A - High compression picture device - Google Patents

Abstract

PURPOSE:To shorten the transmission time by thinning out picture elements in the same positions of individual lines in the proportion of one to plural picture elements and combining two- dimensional decoding to generate picture information having the volume of information before picking-out of picture elements on the basis of decoded picture information. CONSTITUTION:An original is scanned by a reading part 9 to read it as a black-and-white binary signal, and a picking-out part 10 thins out picture elements in the ame positions of individual lines in the main scanning direction in the proportion of one to n numbers of picture elements. The signal encoded by an MR.MMR encoding part 11 is transmitted by a transmitting part 12; and in the reception side, the transmitted signal is received by a transmitting part 13 and is decoded by an MR.MMR decoding part 14, and thinned-out picture elements are forecasted and interpolated by an interpolating part 15, and the result is stored as a hard copy by a recording part 16. The picking-out part 10 is so constituted that picture elements are thinned out in the proportion of one to, for example, three, and the input of a main scanning synchronizing signal (a) is received to generate a synchronizing signal for the picture element to be thinned out by a ternary counter 17, and a signal (e) where picture elements of an picture information input (b) are thinned out is outputted by a shift register 18. Thus, the degradation of the picture quality is relatively small, and the transmission time is shortened considerably.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an image device such as a high compression facsimile device that reduces transmission time.

Conventional configurations and their problems Imaging devices, especially typical facsimile devices, thin out part of the calligraphic information (hereinafter referred to as image information) from a document, capture the image, transmit the remaining image information signals, and then There is a high-compression facsimile machine that interpolates thinned image information, and a conventional example of such a high-compression facsimile machine is the one shown in FIG. 1, for example.

This includes a reading section 1 that reads image information from a document, a decoding section 3 that extracts predetermined pixels from the image information read by the reading section 1,
a transmitting section 4 on the transmitting side that transmits encoded image information; a transmitting section 6 on the receiving side corresponding to this transmitting section 4; a decoding section 6 that decodes the encoded image information; Extraction part 2
The interpolation unit 7 includes an interpolation unit 7 that adds image information to the extracted position, and a recording unit 8 that records the transmitted image information. The encoding unit 3 and the decoding unit 6 include a run-length encoding unit and a run-length decoding unit, respectively, and encode and transmit the continuous length of the inner dimension or black signal. ing. Then, the original is scanned by the reading unit 1 on the sending side, and the image information read into black and white binary is extracted by the extracting unit 2.
As shown in FIG. 2, pixels are thinned out by shifting their positions between even and odd lines, sampled in a zigzag manner every two lines, and input to the run-length encoding unit 3 as image information for one line. In FIG. 2, pixels indicated by diagonal lines are thinned out in the extraction section 2. The encoded image information is
The signal is transmitted from the transmission section 4 via the transmission medium to the transmission section 5 on the receiving side, and guided to the run-length decoding section 6. The decoded image information is input to the interpolation unit 7, where predictive interpolation is performed using four surrounding pixels A, B, c, and D as shown in FIG. 3, and the image information is restored to the original image information. It was later output as a hard copy from the recording unit 8. The reason why the image information is thinned out here is to reduce the amount of encoded information output from the run-length encoder 3 and reduce the transmission cost by shortening the transmission time.

This facsimile machine uses run-length encoding as described above, but the encoding method is a two-dimensional encoding method that has a higher compression rate than run-length encoding, and among them, the International Telegraph and Telephone Consultative Committee (CCITT) ) Recommendation T.4
When considering the application of the MR encoding method standardized for Group 3 facsimile+) by the MMR encoding method, which is an improved version of the MMR encoding method, it is possible to apply the same encoding method to encode the distance between changing points on adjacent lines. The affinity is small and no effect can be expected. Therefore, depending on the type of the transmitted document, there may be a problem that the amount of encoded information is smaller if the MR or MMR encoding method is applied without thinning out.

This problem can also be addressed by increasing the number of pixels to be thinned out and further reducing the amount of encoded information. However, in this case, when performing pixel predictive interpolation after decoding, the distance between the interpolated pixel and the reference pixel increases and the correlation decreases, resulting in greater deterioration of image quality due to prediction mismatch. A new problem arises.

Purpose of the Invention The present invention solves the above-mentioned conventional problems, and applies a two-dimensional encoding method represented by MR and MMR encoding methods to the encoding method, and also reduces the number of pixels to be thinned out to a relatively small number. An object of the present invention is to provide an image device such as a high-compression facsimile device that can reduce the amount of encoded information.

Structure of the Invention In order to achieve the above object, the present invention provides an arbitrary number n of 2 or more in the main scanning direction for read and binarized image information.
By thinning out pixels at the same position on each line at a ratio of 1 pixel to every n pixels, high compression of the image device is achieved, and when performing pixel predictive interpolation after decoding, several improvements in prediction in 1 are achieved. The purpose of this paper is to

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 4 is a diagram showing a schematic configuration of a facsimile device as an image device according to an embodiment of the present invention. In this figure, the reference numeral 9 is a reading unit that scans the original and reads it into black and white binary, and the reference numeral 10 is the same position every line by one pixel in n pixels (n≧2) in the main scanning direction as shown in Fig. 5. 11 is an encoding unit that performs MR or MMR encoding; 12 is a transmission unit on the transmitting side for sending encoded information; and 13 is a receiving side that receives encoded information. The transmission unit 14 is a decoding unit that performs MR or MMR decoding, 15 is an interpolation unit for predictive interpolation of thinned out pixels, and 16 is a unit for obtaining hard copy output. This is the recording section of

FIG. 6 is a diagram showing the circuit configuration of the extracting unit 10 shown in FIG.
pixel, i.e. 3n-1st (n==i.

2...) pixels are thinned out. In this circuit, reference numeral 17 is a ternary counter that receives the main scanning synchronization signal a and generates a synchronization signal for pixels to be thinned out, and reference numeral 18 is a nft register for outputting the thinned out image information. Also, code 3o is a ternary counter 1γ
An inverter 31 for inverting the output signal C of the inverter 30 is an AND gate that performs a logical product between the synchronizing signal a and the output signal of the inverter 30. FIG. 7 is a timing chart showing the operation of the extraction section 10 circuit. The operation of the extraction section 10 will be explained based on this timing chart. The main scanning synchronizing signal a is input to the ternary counter 17, and is ANDed with the inverted value of the output signal C to obtain the waveform shown in FIG. 7d. On the other hand, the image information signal C derived from the reading section 9 is input to the shift register 18 which uses the clock inhibit signal, and its output waveforms become 1d and e, and the 3n-1th image information is thinned out. The thinned out image information e is guided to the MR/MMR encoding unit 11 in FIG. 4, and its synchronization signal is d.

FIG. 8 is a diagram showing a circuit configuration of an interpolation section indicated by reference numeral 16 in FIG. 4. This circuit has a function of predictively interpolating the image information thinned out by the extraction section 10 shown in FIG. 6 above. Of the circuit configuration of this interpolation unit 15, code 19.2
0 is a shift register for obtaining delayed image information for one line, and codes 21, 22, and 23 are shift registers for obtaining one line of delayed image information, respectively.
This is a shift register for obtaining delayed image information for pixels, and numeral 24 is a combinational circuit for predictive interpolation.

Further, reference numeral 25 is a shift register for outputting image information after interpolation, reference numeral 26 is a binary counter for providing a synchronizing signal for input operation to the shift register 25, and reference numeral 27 is for the operation of the soft register 26. It is a ternary counter for creating a clock.

FIG. 9 is a timing chart showing the operation of the interpolation section 15. Based on this timing chart (to explain the operation of the interpolation unit 15'D), the image information derived from the MR and MMR decoding units indicated by 14 in FIG. The output is further input to the 1-line delay shift register 20. A total of 6 pixel pixel signals including the image information, the outputs of the shift registers 19 and 200, and their 1-pixel delayed pixel signals are used for predictive interpolation. The output signal from the prediction combination circuit 24 is input to the combination circuit 24. The output signal from the prediction combination circuit 24 is interpolated between the output signal of the shift register 19 and its one-pixel delayed signal.

The signal is guided from the shift register 25 to a recording section indicated by reference numeral 1e in FIG. The waveform q is the same main scanning signal, and the waveform f is a signal with 1/2 period of the main scanning signal. Every time two pixels are input to the shift register 19, the shift register 25 performs an input operation in synchronization with waveform 1. After the input operation, an operation clock of waveform m is given for 3 clocks, and the shift register 25
Image signals for pixels are output. Since the fundamental period of the waveform m is obtained from the waveform f, the shift register 26 can always complete the 3-bit sint operation for the input operation amount. A synchronization signal of the image signal after interpolation is given by a waveform m. FIG. 10 is a diagram showing the positional relationship between input and output image signals of the predictive interpolation combination circuit indicated by reference numeral 24 in FIG. 8, and FIG. 11 is a diagram showing the correspondence with signal lines. In this figure, from the top, F, C,
E, B, D.

The order A matches the order of the input signals of the predictive combination circuit 24 in FIG. FIG. 12 is a truth table of the prediction combination circuit 24 of FIG. 11, where 1 represents a black pixel and the predicted value represents a combination of black. This is because from the statistical properties of images, the pixel of interest in Figure 1 The predictive logic function is calculated from x=B×(D→−E+F)×E*(A+B×C) where*: logical product ten: logical sum.

This is what I thought of. Here, × indicates a predicted value.

Figure 13 shows the case where MMR encoding is performed on image information obtained by reading CCITT facsimile test charts 1 to 8 at a density of 8 pixels/mm in the main scanning direction and 3.85 lines/mm in the sub-scanning direction. , is a comparison diagram of the amount of encoded information when MMR encoding is performed after image information is thinned out at a ratio of one pixel out of every three pixels by the facsimile apparatus according to the present invention. As is clear from this figure, the facsimile apparatus according to the present invention reduces the amount of information by about 13% on average. What can be said from this is that although the facsimile machine of the present invention has not suffered much deterioration in image quality compared to facsimile machines before applying the present invention, it has achieved a significant reduction in transmission time by reducing the amount of information. It becomes clear that

As described in detail, according to the present invention, pixels at the same position in each line are thinned out for two or more pixels in binarized calligraphic information, and two-dimensional decoding is combined, and after decoding, Since the calligraphy information with the amount of information before pixel extraction is created based on the calligraphy information of This has the effect of realizing a significant reduction in transmission time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a control system of a conventional facsimile machine that performs thinning and interpolation of image information, FIG. 2 is a pixel arrangement diagram showing the image information thinning method of the conventional facsimile machine shown in FIG. 1, and FIG. The figure is a pixel array diagram showing the positional relationship between the interpolation position and the reference pixel in the image information interpolation method of the conventional facsimile device shown in FIG. 1, and FIG. 4 is the control of the facsimile device showing one embodiment of the present invention. Block diagram of the system, Figure 5 is the 4th
Figure 6 is a pixel array diagram showing a method of thinning out image information in the extraction unit incorporated in the control system shown in Figure 4. Figure 6 is a circuit configuration diagram of the extraction unit incorporated in the control system shown in Figure 4. Figure 8 shows the operation timing chart of the first part of extraction shown in Figure 4.
9 is a diagram showing the operation timing chart of the interpolation section shown in FIG. 8, and FIG. 10 is a diagram of the facsimile machine shown in FIG. 4. A pixel array diagram showing the positional relationship between the interpolation position and the reference pixel in the information interpolation method. FIG. 12 is a diagram showing the truth table of the predictive combinational circuit shown in FIG. 11, and FIG. 13 is a diagram showing how the coding efficiency is improved in the facsimile apparatus according to the present invention. 1.9...reading section, 4,12...transmission section (calling side), 5,13...transmission section (receiving side)
, 7, 16... Interpolation section, 8, 16 - Recording section, 11
... MRMMR encoding unit, 14...MR, MM
R decoding unit, 17... Ternary counter, 18...
Shift register, 19.20...1 line delay shift register, 24...Predictive combinational circuit. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure @2 Main direction button Figure 3 Figure 4 Figure 5) L tatami direction Figure 6 Q r ”-] 1 1 Figure 7 e f34G'/ Figure 8 S Mail L --- 1- −−−−−−−−−−−−−−−1−−−
Figure 9 m - Figure 10 Figure 11 Figure 12

Claims (1)

[Claims] an extracting unit that thins out the m-th pixel at the same position in multiple lines at a rate of one pixel for every n pixels in the main scanning direction from the binarized calligraphy information; a two-dimensional encoding unit; and the two-dimensional encoding unit. a decoding unit that performs decoding corresponding to
At the bit-th pixel location, the (m-1)th bit of the line of the drawing signal and the (m+)th bit of the previous line or the next line.
1) The AND of the pixel corresponding to the bit-th bit, the (m+1)th bit of the relevant line, and the (m-1)th bit of the previous or next line.
) A high-compression image device having an interpolation unit that predicts and reproduces a pixel by a logical product of pixels corresponding to the bit.