JPS58165482A - Encoder of color picture data - Google Patents

Abstract

PURPOSE:To encode only data having correlation to the position of picture element group when the result of prediction is correct and to encode color data and data having correlation with position when not correct, by performing the prediction based on the data relating to inputted color picture data. CONSTITUTION:A run length and color discrimination circuit 7 which are same as a run detection circuit 2, converts a color picture data into a run length data and a color data. The run length data and the color data are given to a prediction circuit 8 and to a memory 9. The prediction circuit 8 predicts the color of inputted run newly based on a stored data of the memory 9. Further, the run length data and the color data are given to a code converting circuit 10. The circuit 10 encodes the run length data and the color data, the same as a code converting circuit 3. Said prediction circuit 8 controls the operation of the circuit 10, depending whether or not the predicted result is coincident with the color data inputted actually, that is, whether the result of prediction is correct or not.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image data encoding system, and more particularly to color-image data encoding, for example, run-by-run encoding of color image data.

When transmitting color image data of a multicolor image consisting of not only black and white but also a plurality of colors, the amount of information is much larger than when transmitting black and white image data. Therefore, color image data is compressed by encoding and transmitted.

11tIJ is a block diagram showing an example of a conventional color image data encoding and decoding method. In the figure, color image data is input to the encoded value w1 in m-element order. This color-image data is applied to the run detection circuit 2,
converted to run data.

Here, a run is a series of mJIIIs having the same color and arranged in the same scanning line direction. That is, the run detection circuit 2 converts the color ii image data into run length data (the number of pixels in a run) and color data for that run. As a result, the color image data is considerably compressed. Furthermore, the output of run detection circuit 2 is applied to code conversion circuit 3 for data compression. The code conversion circuit 3 encodes the given run length data and color data,
Transmit. On the receiving side, this transmitted encoded data is single-layered by the ll@ conversion circuit 4 and converted into the original color image data. Note that the decoding circuit 4 is essentially the same as the encoding circuit 1.

In the method shown in FIG. 1, color data must be encoded and transmitted for each run. Therefore, the color data symbol @
- Is there a lot? , transmission takes a lot of effort. Furthermore, a memory with a large storage capacity is required to store code data.
,・：：．

Other information on color, how to reduce the amount of,
knee.

As a method, there is a method in which the screen is divided into a plurality of 11 nicks, and a limited number of colors (for example, two colors) are used to color each screen. The expressive power is limited and blocks must be taken into account at the stage of creating 1lIIli11.

Therefore, the main object of the present invention is to provide a color image data encoding device that can reduce the amount of color information without imposing any restrictions on the image.

To summarize, the present invention encodes color image data for each pixel group of the same color, in which color data of a newly input pixel group is encoded based on data related to already input color image data. predict, and when the prediction result is correct, encode only the data correlated to the m prime group position,
When the prediction result is incorrect, color data and data correlated to position are encoded.

The above-mentioned 1. The purpose and other objects and features of ., will become more apparent from the following detailed description of q'i'L/ with reference to allllll.

FIG. 2 is a block diagram showing an embodiment of the present invention.

In the configuration, color image data is provided to a run length/color identification circuit 7 of an encoding circuit 5. This run length/color discrimination circuit 7 converts color image data into run length data and color data, similarly to the run detection circuit 2 described above. This run length data and color data are given to the prediction circuit 8, and
memory 9. The prediction circuit 8 predicts the color of a newly inputted run based on the data stored in the memory 9.

Furthermore, run length data and color data are code converted @Route 10
given to. This code conversion circuit 10 encodes run length data and color data similarly to the code conversion circuit 3 described above. Here, the prediction circuit 8 determines whether the predicted result matches the actually input color data, that is, whether the predicted result is correct or incorrect.
control the behavior of As will be described later, when the prediction result is correct, only run length data is encoded and transmitted at the code conversion stage sio. Furthermore, if the prediction result is incorrect, both run length data and color data are encoded and transmitted.

The code transmitted as described above is given to the code identification circuit 11 of the decoding circuit 6. The code identification circuit 11 identifies whether the supplied code is a run length code or a color code, and outputs the run length code and color code separately. The run length code is given to a run length code inverse conversion circuit 12, where it is inversely converted into the original run length data. Further, the color code is given to a color code inverse conversion circuit 13, and is inversely converted into the original color data. The outputs of the run length code inverse conversion circuit 12 and the color code inverse conversion circuit 13 are given to a prediction circuit 14. This prediction circuit 14 predicts the colors of the four lines in the same manner as the prediction circuit 8 described above when only run length data is given.

Note that the memory 15 has already stored run length data and color data that have been logged, and the prediction circuit 14 makes predictions based on this stored data. And prediction episode 11
14 outputs the predicted color data and the given run length data as the run data at that time. Furthermore, when the prediction circuit 14 is given both run length data and color data, it outputs both of the given data as is as run data.

In operation, the color of run X to be encoded is now (X), and the color of run X predicted by the prediction circuit 8 is (X'
). Also, if the run length of run X is (LX),
The sign Ji8COX of the transmitted run X is expressed by the following equation.

However, F (LX) is the code C representing the run length (LX).
, and G(X) is a code representing color (X).
, Figures 3(a,) to 6) are diagrams showing various run arrangements. In this way, each 5>(1)y is stored in the memory 9.
>Mkf-) J: @Deni..., -pg"' memory 87°. Below, with reference to this Fig. 3 q!l, pre-5uii path 8 (7) pre-1111 fF 4C'6゛r @°±1
1〒.

Now, the color of run A (A) is 91I! , Suppose that −, De 4. of runs near run A. - Evening is used for prediction. This takes advantage of the color scheme of orchids in the 1. - image. Here, it is clear that run B immediately before run A has a different color than run A, so run B
data will be excluded from the predicted data.

First, as shown in Fig. 3(a), in the scanning line immediately before run A, if there is only one run that touches run 8, run C (run B is excluded from the prediction data), then run C
The color data (C) of run A is predicted as the color data of run A.

Next, as shown in FIG. 3(b), if there are multiple runs such as runs C, Oa, and E that are in contact with run A, the color data of the run that is in contact with run A with the largest number of A
(It is pre-11 as 9-color data.Instead of determining which run's color is the predicted color based on the Im prime number that is in contact with run A, prediction is simply performed based on the position of the run that is in contact with the run of interest. Even if -11j' the color of run D, which teaches the color of the leftmost run C, is unconditionally changed to run A.
The predicted color may be set as the predicted color, or the color of the rightmost run E may be unconditionally set as the predicted color of the run.

Next, as shown in FIG. 3(c) and 4S, if there is no run touching run A, it is determined whether there is a run different from run B within a certain distance from run A in the scanning line direction. be judged.

If a run C is found within a certain distance, the color data (C) of this run C is predicted as the color data of run A. If there are multiple runs C and D within a certain distance from run A in the scanning line direction as shown in FIG.
is predicted as run A color data. Note that instead of determining which run's color is the predicted color based on the distance from the run of interest, prediction may be performed simply based on the position of a run within a certain distance in the scanning line direction from the run of interest.

For example, the color of run C on the left may be unconditionally set as the predicted color of run A, or the color of run D on the right may be unconditionally set as the predicted color of run A.

Next, as shown in FIG. 3(e), if there is no run that touches run A, and if there is no run that intersects with run B within a certain distance from run A in the scanning line direction, then Run B
The color data (C) of the immediately preceding run C is predicted as the color data of the run A.

Note that if the scanning line where run A is located is the topmost scanning line of the image, there may be no run used for prediction data in pixels near run A. In such a case, for example, the color of the background of the image is initially set in the memory 9, and this initially set color is used as prediction data.

4A and 48 are flowcharts for explaining the operation of the prediction circuit 8. FIG. Below, Figures 2 to 48
11, the operation of this embodiment will be explained.

First, the run length/color discrimination circuit 7 converts color image data into color data and run length data. The color data and run length data are provided to the memory 9 and stored therein. Also,
The prediction circuit 8 predicts the color data of the target run A according to the operations of steps (abbreviated as S in the figure) 1 to 14 of the flowchart shown in FIG. 4A. Since this operation will be easily understood from the explanation of FIG. 3, further explanation will be omitted here.

Next, in step 15 shown in FIG. 48, the prediction circuit 8 determines whether a run selected from run B is within a certain distance from run A in the scanning line direction.

If it is within a certain distance, it is determined in step 16 whether or not the run 8 is in contact with run A. If it is determined that they are in contact with each other, as shown in FIGS. 3(a) and (b), the color of the run with the largest number of neighbors Ii is determined as the predicted color of run A in step 17. . Then, in step 18, if the actual color of run A is the same as the predicted colorimetry, in other words, if the prediction is correct, in step 19, the sign of the run length of run A, only the 1° conversion, is added to the code table. Instruct the test circuit to be 10 km. Accordingly, the code conversion circuit 10 has a longer run: converts only the code to ll1,
It is transmitted to circuit 6. On the other hand, if the color entered in the run is different from the predicted color, that is, if the prediction is wrong, the code conversion circuit 10 is instructed to convert the color and run length of τ run A in step 20. Accordingly, the code conversion circuit 10 converts the run A
The run length and color are both encoded and transmitted to the I@ encoding circuit 6. The code conversion circuit 10 then operates such that the color code and run length code transmitted when the prediction is incorrect are identified as the run length code transmitted when the prediction is correct.
An identification code is transmitted before or after the run length code that is transmitted when the prediction is correct. Note that instead of transmitting this identification code, the run length code itself may be an identifiable code.

On the other hand, if it is determined in step 16 above that the run that separates from run B is not in contact with run A, that is, in the case shown in 3rd Il (C) and (d-), the operation in step 21 is performed. will be carried out. That is, the '4th
The color of the run with the longest indicated distance held in step 12 in Figure A is taken as the predicted color of run A. Hereafter, steps 18 to 20, )llb engineering.ゎti'h'. □、
□(1)) sfya.

If it is determined that the run associated with run 8 is not within a certain distance from run A, that is, in the case shown in FIG. The color of the run is read from memory 9. Then, the color of the run read out in step 23 is run A.
This is the predicted color.

Subsequently, the operations of steps 18 to 20 described above are performed.

In addition, in the logging circuit 6, the prediction circuit 14 only when color data is not given from the color code inverse conversion circuit 1i13,
Perform the preparation as explained in FIG. 3. Therefore, the prediction circuit 14 outputs data that is exactly the same as the color data and run length data output from the run length/color identification path 7.

As described above, when the color predicted by the prediction circuit 8 matches the color of the actual data, the color data of that run is not encoded or transmitted, so the amount of code to be transmitted can be reduced.

No. 511 is a block diagram showing another embodiment of the present invention. In the configuration, the same parts as in FIG. 2 are given the same reference numerals, and the explanation thereof will be omitted. In this embodiment, memory 90 of encoding circuit 100 stores color-data as is. Then, the prediction circuit 80 converts the color image data read from the memory 90 into run length data and color data, which are used as prediction data. Furthermore, in the decoding circuit 600,
Like the memory 90, the memory 150 stores color image data for each pixel. Furthermore, the output of the prediction circuit 140 is color uniform data in units of pixels, and the format of the image data referred to in prediction is also in units of pixels.

Note that in the embodiments described above, run data included in the scan line immediately before the run to be predicted is mainly used as reference prediction data, but data for runs included in a plurality of scans above the run to be predicted are used as reference prediction data. data may be used as prediction data. For example, when using run data included in the two scan groups above the run of interest A as prediction data,
As shown in Figure 6, the color of the run is (E)-(C)7' (
8) and (F)-(D)f (B), it is predicted that runs of the same color are connected in a downward-to-right direction to form a fist, and the color of run A is the same as that of run C. can be predicted to be equal to the color of In this way, if a plurality of scan runs are used as prediction data, the configuration state of the image can also be taken into account, and prediction can be further improved. Therefore, it is possible to further reduce the amount of code. In the case of the embodiment shown in FIG. 2, the color of run D, which has the largest number of pixels in contact with run A among the runs that are in contact with run A, is predicted as the color of run A.

Further, in the embodiment described above, one color data and run length data are used as data representing a run.
Instead of this run length data, τ run break position (address) data may be used. That is, as long as the data correlates with the position of the run, distance calculations and pixel counts can be performed. :, 1::,,
11:.

・, 11, 100ゝ・50 shots m
The amount of code for image data can be significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating a conventional color image data encoding and image layering method. FIG. 2 is a block diagram showing an embodiment of the present invention. FIG. 3 is a diagram showing various arrangements of runs. Figures 4A and 48! li is an O-chart for explaining the prediction circuit 8 and its operation. FIG. 5 is a block diagram showing another embodiment of the invention. FIG. 6 is an illustrative diagram for explaining an example in which runs of a plurality of scanning lines are used as prediction data. - In the figure, 7 is the run length/color discrimination circuit, 8.14.80
and 140 is a prediction circuit, 9.15.90 and U150
1 is a memory, and 10 is a code conversion circuit. Agent Kuzu 1 No Tsune - (1 other person), 1' 11[: Figure 3, Figure 4B, Figure 5, Figure 6, voluntarily to write amendments to the procedure) 1 opinion i'1lih government office], = J) 1' Display of l Patent application 1987-4
No. 98118 2゜ Title of the invention Color - Su data encoding device 3, ) + Li City holder 5, Detailed description of the invention in the specification subject to amendment - and Drawing 6, Contents of amendment (1) Specification No. Change “encoding” in line 11 of page 2 to “code,”
Corrected to ``to change''. (2) Lines 9 and 10 of page 3 of the specification are corrected to read as follows. Convert to written data. Note that the decoding circuit 4 basically performs a conversion process that is inverse to the encoding asi. (3) r on page 7, line 9 (line 12 from the bottom) of the specification
In the case of (X)-(X')", change to "(×)≠(X')
Correct to "In the case of". To (4), page 8, line 5 to line 1119 of the specification is corrected to the following sentence. 11 , :, First, as shown in Fig. 3 < a , >, 1', in the scanning line immediately before run A, there is only one run, run c, which has a color different from run i and is in contact with run A. (A run having the same color as run B is excluded from the prediction data for the above-mentioned reason. The same applies to cases 311(b) to 311(e) below). ), the color data of run C (C) is predicted as the color data of run A. (5) "Abuts r-run A" in pages 8, lines 11 and 12 of the specification, lines 2 and 3 of the 9th section, and lines 19 and 20 of the 9th section is replaced with "Run A". It is corrected to ``It has a color that is adjacent to and contrasts with Run B''. (6) Specification page 9, line 4, member 10, line 1, 11
In line 4 of page 11, line 7 of page 11, lines 11 to 12 of page 12, and line 19 of page 12, the word ``okonari'' is corrected to ``have a different color.'' (7) "Multiple runs" in line 9 of Specification 119 is corrected to "Multiple runs with E-run B and rising white." (8) Correct "Flowchart" in Line 11 of Part 10 of the specification to "Flowchart." (9) Lines 5 to 8 of Member 12 of the specification are corrected to the following sentence. An identification code is transmitted before the color code so that the transmitted color code is identified as a run length code. Note that the identification code (10) "The r run length code itself" in the 9th line of the 12th member of the specification is corrected to "The color signal itself is the run length code." (11) "Predicted rate" on page 15, line 4 of the specification is corrected to "predicted match rate." (12) Figure 3 is as attached. (13) Figure 4A is as attached. On the station

Claims (1)

[Scope of Claims] A color image data encoding device for encoding color image data input sequentially, the color image data being encoded in units of the same color by data and color data correlated to the position of a pixel group. 9 conversion means; storage means for storing at least part of the data related to the color image data that has already been input; Prediction means for predicting based on data stored in the means; data encoding means for encoding data and color data correlated to the position; when the prediction result of the prediction means is correct, controlling the data encoding means; means for controlling the data encoding means to encode only the data correlated with the position, and when the prediction result of the prediction means is imposed, controlling the data encoding means to encode only the data correlated with the color data and the position. A color-image data encoding facility comprising means for encoding.