JP4766230B2 - Encoding device, data processing device, decoding device, and program - Google Patents

Description

  The present invention relates to an image processing method for encoding or decoding image data.

As a method of encoding paying attention to data autocorrelation, there are, for example, run length encoding, JPEG-LS, LZ encoding (Ziv-Lempel encoding), and the like. In particular, in the case of image data, since neighboring pixels have a high correlation, it is possible to encode image data at a high compression rate by paying attention to this point.
Patent Document 1 discloses a predictive coding method using a plurality of prediction units.
JP 2000-350215 A

  The present invention has been made from the above-described background, and an object thereof is to provide an encoding device that encodes data at a higher compression rate.

[Encoder]
In order to achieve the above object, an encoding apparatus according to the present invention is an encoding target using image data of a reference area at a predetermined relative position with respect to image data of an attention area to be encoded. The attention part data should be registered on condition that the first prediction means for predicting the attention part data, the prediction data predicted by the first prediction means, and the attention part data do not match. A registration determination unit that determines that, a data storage unit that stores target portion data determined to be registered by the registration determination unit, and any one of the target portion data stored in the data storage unit, second prediction means for predicting the target partial data to be encoded, the prediction result by the first prediction means, and, based on the prediction result by the second prediction unit, wherein the note And a code generating means for generating code data of the partial data.

Preferably, the method further includes a prediction error generation unit that generates a difference between the attention partial data and the prediction data predicted by the first prediction unit as a prediction error, and the code generation unit includes the first generation unit. Based on the prediction error generated by the prediction error generation unit when the prediction data predicted by the prediction unit and the prediction data predicted by the second prediction unit do not match the target partial data. Then, code data of the target portion data is generated, and the registration determining unit determines that the target portion data should be registered on the condition that the code data is generated based on the prediction error.

Preferably, the second prediction means selects the target partial data that does not match the prediction data predicted by at least said first prediction means, from the target partial data stored by said data storage means Thus, it is used to predict the target partial data to be encoded .

Preferably, the registration determination means determines that the target partial data having a predetermined data value, a target partial data that should not be registered.

In addition, the encoding apparatus according to the present invention predicts target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of a target region to be encoded. First preliminary prediction means; preliminary data storage means for storing the target portion data on condition that the prediction data predicted by the first preliminary prediction portion and the target portion data do not match; The second preliminary prediction unit that predicts the target partial data to be encoded using any target partial data stored in the preliminary data storage unit, and the first preliminary prediction unit prediction data and the prediction data predicted by the second preliminary prediction means, and an error evaluating means for evaluating the difference between the target partial data to be encoded, the error Depending on the result of evaluation by the valence unit, the target partial data to be encoded, predictive data predicted by said first preliminary prediction means, and, substituted with prediction data predicted by the second preliminary prediction means Data replacement means, at least a prediction method applied by the first preliminary prediction means, and a prediction method applied by the second preliminary prediction means, and at least a part of attention by the data replacement means Predictive encoding means for predictively encoding data in which partial data is replaced with any predictive data.

Preferably, the target partial data to be encoded is image data corresponding to a part of an image.

[Data processing equipment]
In addition, the data processing apparatus according to the present invention predicts target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of a target region to be encoded. First prediction means, data storage means for storing the target portion data on condition that the predicted data predicted by the first prediction means and the target portion data do not match, and the data A second prediction unit that predicts the target partial data to be encoded using any target partial data stored in the storage unit; prediction data predicted by the first prediction unit; and For the prediction data predicted by the second prediction means, an error evaluation means for evaluating a difference from the target partial data to be encoded, and an evaluation result by the error evaluation means And Flip has a portion of interest data to be encoded, predictive data predicted by said first prediction means, and, a data replacement means for replacing the forecast data predicted by said second prediction means.

[Decryption device]
Further, the decoding apparatus according to the present invention is encoded data obtained by encoding the prediction data of the target partial data predicted using the image data of the reference region at a predetermined relative position with respect to the image data of the target region , Decoding means for decoding the code data of the partial data of interest that did not match the prediction data, a reference position is specified from the code data decoded by the decoding means, and the reference data corresponding to the reference position , And based on the read reference data, the data reference means for generating the attention partial data, and the attention partial data is generated based on the difference data included in the code data decoded by the decoding means. Difference processing means, storage means for storing the attention partial data generated by the difference processing means, and attention partial data stored by the storage means From the, according to the identified reference positions in the data reference means, and a data selection means for selecting one of the target partial data.

[program]
The program according to the present invention includes a step of predicting target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of the target region to be encoded. Any one of the step of registering the target partial data as a prediction candidate on the condition that the predicted data predicted and the target partial data do not match, and the target partial data registered as the prediction candidate Are used to predict the target partial data to be encoded, the prediction result predicted using the image data of the reference region at the predetermined relative position , and the target partial data of the prediction candidate And generating a code data of the target partial data based on the predicted result.

In addition, the program according to the present invention includes encoded data obtained by encoding prediction data of attention partial data predicted using image data of a reference region that is in a predetermined relative position with respect to image data of the attention region, and the prediction The code data of the partial data of interest that did not match the data is decoded, the reference position is specified from the decoded code data, the reference data corresponding to the reference position is read out, and the reference data is read out A step of generating the target portion data; and a step of generating the target portion data when the decoded code data indicates the difference data; and the target portion data generated based on the difference data as a prediction candidate. And when the decoded code data indicates one of the prediction candidates, it is registered as the prediction candidate. From the target partial data are, and a step of selecting one of the image data to the computer.

  According to the encoding apparatus of the present invention, image data can be encoded at a higher compression rate.

[Background and outline]
First, in order to help understanding of the present invention, its background and outline will be described.
FIG. 1 is a diagram for explaining an encoding method for encoding input data while dynamically changing a data dictionary. FIG. 1A shows an encoding using a data dictionary that slides according to a region of interest. FIG. 1B illustrates an encoding method having a data dictionary in a plurality of directions with respect to a region of interest.
For example, in a predictive encoding method such as the LZ77 encoding method, prediction data is generated with reference to a pixel value at a predetermined reference position, and the generated prediction data and partial data of a target portion to be encoded are obtained. If they match, the reference position of the matched prediction data is encoded as the code data of the target portion.
More specifically, as illustrated in FIG. 1A, the LZ77 encoding method has the longest match with the data of the attention area within the window area that slides according to the position of the attention area to be encoded. The longest matching string is searched, and the matching information (position information of the longest matching string, etc.) is encoded.

  Further, as shown in FIG. 1B, reference positions A to D are set at positions displaced in the main scanning direction and / or the sub-scanning direction with respect to the attention area (target pixel X), Using the data (pixel values) of the set reference positions A to D as a data dictionary, the matching information (such as the identification information of the reference position where the pixel values match) between the pixel value of the reference pixel and the pixel value of the target pixel X is encoded. There is also a method to make it.

FIG. 2 is a diagram illustrating an input image. FIG. 2A illustrates an input image including a line in the sub-scanning direction, and FIG. 2B illustrates an input image including a dither pattern.
When the input image illustrated in FIG. 2A is encoded, in the LZ77 encoding method described with reference to FIG. 1A, the same pixel value (excluding the blank portion) exists in the window area. Therefore, the line image included in the input image cannot be efficiently encoded.
Note that the method described with reference to FIG. 1B can be efficiently encoded because the pixel values of the reference position B or the reference position C and the target pixel X match in the area of the line image.
However, as illustrated in FIG. 2B, when there is an isolated point in the input image, the method described with reference to FIG. Since the pixel values do not match even at the reference position, it cannot be encoded efficiently.

Therefore, the image processing apparatus 2 according to the present embodiment provides an independent dictionary that does not depend on the position of the attention area in addition to the data dictionary that dynamically changes according to the position of the attention area. In other words, the present image processing apparatus 2 performs a predictive coding process by providing a predictor that does not depend on the relative position with the attention area in addition to the predictor that depends on the relative position with the attention area.
This makes it possible to refer to data deviating from the dynamic data dictionary (data that cannot be predicted by a predictor that depends on the relative position to the region of interest), and can more easily identify lines and isolated points in the sub-scanning direction shown in FIG. It becomes possible to encode efficiently.

[Hardware configuration]
Next, a hardware configuration of the image processing apparatus 2 in the present embodiment will be described.
FIG. 3 is a diagram illustrating a hardware configuration of the image processing apparatus 2 to which the encoding method and the decoding method according to the present invention are applied, centering on the control apparatus 21.
As illustrated in FIG. 3, the image processing apparatus 2 includes a control device 21 including a CPU 212 and a memory 214, a communication device 22, a recording device 24 such as an HDD / CD device, an LCD display device or a CRT display device, and a keyboard. A user interface device (UI device) 25 including a touch panel and the like is included.
The image processing apparatus 2 is, for example, a general-purpose computer in which an encoding program 5 (described later) and a decoding program 6 (described later) according to the present invention are installed as a part of a printer driver, such as a communication device 22 or a recording device 24. The image data is acquired via, and the acquired image data is encoded or decoded and transmitted to the printer apparatus 3.

[Encoding program]
FIG. 4 is a diagram illustrating a functional configuration of the encoding program 5 which is executed by the control device 21 (FIG. 3) and implements the encoding method according to the present invention.
As illustrated in FIG. 4, the encoding program 5 includes a position-dependent prediction unit 500, an independent prediction unit 510, a prediction error calculation unit 520, a run counting unit 530, a selection unit 530, and a code generation unit 550.

In the encoding program 5, the position-dependent prediction unit 500 generates prediction data based on the partial data at the reference position corresponding to the position of the target portion to be encoded, and the generated prediction data and the target portion The partial data is compared and the comparison result (prediction result) is output to the run counter 530.
More specifically, when encoding the pixel value of the pixel of interest, the position-dependent prediction unit 500 reads out the pixel value of the reference position at a predetermined relative position with respect to the pixel of interest, and the read reference Using the pixel value at the position as prediction data, the prediction data and the pixel value of the target pixel are compared.
As illustrated in FIG. 1B, the position-dependent prediction unit 500 of this example uses the pixel values of a plurality of reference positions A to D corresponding to the position of the target pixel X as prediction data, and the pixel value of the target pixel X Are compared with the pixel values (prediction data) of the reference positions A to D, and when the pixel values match (that is, when the prediction is correct), the reference position ID for identifying the reference position is run-counted. When the prediction data does not match, the fact that they did not match is output to the run counting unit 530.
The position-dependent prediction unit 500 may generate at least one prediction data with reference to at least one reference position. For example, the position-dependent prediction unit 500 may generate prediction data with reference to only the reference position A. In this case, the code data generated by the prediction data by the position-dependent prediction unit 500 is the same as that generated by the run length encoding method (run length encoding method).

The independent prediction unit 510 generates prediction data of the target portion using a prediction method that does not depend on the position of the target portion, compares the generated prediction data with the partial data of the target portion, and compares the result ( The prediction result is output to the run counting unit 530.
Here, “independent of the position of the target part” means that it is not defined by the relative position with the target part (target pixel), but “a data group processed before the target part”. In this case, the dependency in the meaning of “exists in (image region)” is excluded. That is, the prediction method by the independent prediction unit 510 may be dependent on the position of the target portion in that it uses partial data existing in a data group (image region) processed before the target portion. It is done.
More specifically, the independent prediction unit 510 selects any one of pixel values stored as prediction data candidates as prediction data, and compares the selected prediction data with the pixel value of the target pixel. Output to the run counter 530.
For example, the non-dependent prediction unit 510 performs this attention when the prediction data from the position-dependent prediction unit 500 does not match the pixel value of the target pixel (when these prediction data do not match). The pixel value of the pixel is stored as a candidate for prediction data.
As a result, pixels that are not correctly predicted by the position-dependent prediction unit 500 (for example, pixel values of isolated points) are registered as prediction data candidates and used for prediction by the independent prediction unit 510.
The independent prediction unit 510 stores the pixel value of the target pixel for which the prediction error is calculated as a prediction data candidate on the condition that the prediction error calculated by the prediction error calculation unit 520 is encoded. May be.

The prediction error calculation unit 520 generates prediction data of the attention portion by a predetermined prediction method, calculates a difference between the generated prediction data value and the partial data value of the attention portion, and the calculated difference Is output to the selection unit 540 as a prediction error.
More specifically, the prediction error calculation unit 520 predicts the pixel value of the target pixel based on the pixel value of a predetermined reference position (a reference position associated with the position of the target pixel X), and the predicted value Is subtracted from the actual pixel value of the pixel of interest and output to the selection unit 540 as a prediction error value. The prediction method of the prediction error calculation unit 520 only needs to correspond to the prediction method in the decoding process of code data.
The prediction error calculation unit 520 of this example uses a pixel value at the same reference position (reference position A) as that of the position-dependent prediction unit 500 as a predicted value, and calculates the predicted value and the actual pixel value (the pixel value of the target pixel X). The difference is calculated as a prediction error value.
When the reference position A does not actually exist in the image as in the case where the target pixel X is at the leftmost end, the prediction error calculation unit 520 uses the default value (the same default value as that of the decoding program) as the predicted value. As shown in FIG.

The run counting unit 530 counts the number of consecutive hit prediction data based on the comparison result input from the position-dependent prediction unit 500 and the comparison result input from the non-dependent prediction unit 510.
More specifically, in the run counting unit 530, based on the reference position ID input from the position-dependent prediction unit 500 and the reference position ID input from the non-dependent prediction unit 510, the same reference position ID is consecutive. The reference position ID and its continuous number are output to the selection unit 540.
The run counting unit 530 of this example includes the reference position ID and the reference position ID counted by the internal counter when the prediction data by the position-dependent prediction unit 500 and the non-dependent prediction unit 510 do not match the pixel value of the target pixel. The continuous number is output.

  The selection unit 540 selects the longest continuous reference position ID based on the reference position ID and the continuous number input from the run counting unit 530 and the prediction error value input from the prediction error calculation unit 520. The reference position ID, the number of consecutive positions, and the prediction error value are output to the code generation unit 550 as coincidence data.

  The code generation unit 550 assigns a code to the reference position ID, the number of continuations, and the prediction error value input from the selection unit 540, and assigns the assigned code to the communication device 22 (FIG. 3) or the recording device 24 (FIG. 3). Output to etc.

FIG. 5 is a diagram illustrating the configuration of the independent prediction unit 510 (FIG. 4) in more detail.
As illustrated in FIG. 5, the independent prediction unit 510 includes a registration control unit 512, a candidate value storage unit 514, a candidate value selection unit 516, and a match determination unit 518.
The registration control unit 512 selects partial data to be registered as a candidate for prediction data, and registers the selected partial data (pixel value) in the candidate value storage unit 514. More specifically, the registration control unit 516 determines that the position-dependent prediction unit 500 (FIG. 4) detects that all prediction data does not match the pixel value of the target pixel. The pixel value is registered in the candidate value storage unit 514.
The registration control unit 512 of this example sets the upper limit of the number of entries registered in the candidate value storage unit 514 to two, and the entry with the earlier registration order in the candidate value storage 514 (pixel value that is a candidate for prediction data) Each entry (candidate pixel value) is managed by giving a high priority.

Further, the registration control unit 512 is based on a preset registration prohibition condition, even if all the prediction data does not match the pixel value of the pixel of interest in the position-dependent prediction unit 500 (FIG. 4). The registration of the pixel value of the target pixel in the candidate value storage unit 514 is prohibited. The registration prohibition condition is, for example, “matching a predetermined data value”.
The registration control unit 512 of this example prohibits registration of pixel values corresponding to these colors, with the registration prohibition condition being coincident with pixel values corresponding to the background color, black, and white. This is because the background color, black and white are less likely to be isolated points compared to other colors.

The candidate value storage unit 514 stores the pixel value registered by the registration control unit 512 as a candidate value of prediction data.
The candidate value storage unit 514 of this example stores two pixel values as candidate values of prediction data, the pixel value registered earlier is the first candidate value, and the pixel value registered later is the second candidate value. Remember as.

The candidate value selection unit 516 outputs any partial data from the partial data (candidate values) stored in the candidate value storage unit 514 to the match determination unit 518 as predicted data.
For example, the candidate value selection unit 516 selects candidate values on the condition that the prediction data does not match the prediction data applied by the position-dependent prediction unit 500.
In this example, the candidate value selection unit 516 selects a candidate value that does not match the pixel value at the reference position A from the pixel values stored in the candidate value storage unit 514. Note that if none of the pixel values (first candidate value and second candidate value) stored in the candidate value storage unit 514 matches the pixel value at the reference position A, the candidate value selection unit 516 selects the first candidate. Select a value.

The coincidence determination unit 518 compares the partial data of the target portion with the prediction data input from the candidate value selection unit 516, and outputs the comparison result to the run counting unit 510 (FIG. 4).
The coincidence determination unit 518 of this example compares the pixel value of the target pixel with the pixel value (prediction data) input from the candidate value selection unit 516, and identifies the independent prediction unit if they match. The reference position ID (that is, the reference position ID indicating that the pixel value stored in the candidate value storage unit 514 is a reference destination) is output to the run counting unit 530.

FIG. 6 is a diagram for explaining the encoding process performed by the encoding program 4 (FIG. 4). FIG. 6A illustrates a reference position referred to by the position-dependent prediction unit 500, and FIG. B) illustrates the codes associated with the respective reference positions, FIG. 6C illustrates the codes associated with the independent prediction unit 510, and FIG. 6D illustrates the code generation unit. The code data produced | generated by 550 is illustrated.
As illustrated in FIG. 6A, the reference position of the position-dependent prediction unit 500 is set as a relative position with respect to the target pixel X. Specifically, the reference position A is set upstream of the target pixel X in the main scanning direction, and the reference positions B to D are set on the main scanning line above the target pixel X (upstream in the sub-scanning direction). .

In addition, as illustrated in FIG. 6B, the reference positions A to E are associated with codes.
Similarly, as illustrated in FIG. 6C, codes are also associated with prediction data by the independent prediction unit 510.
When the pixel value (prediction data) read from any reference position matches the pixel value of the target pixel X (that is, when the prediction is correct at any reference position), the run counter 530 (FIG. 4) increases the number of consecutive reference position IDs for the reference position where the prediction is correct, and when the prediction data by the independent prediction unit 510 is correct, the run counting unit 530 performs the independent prediction. For the prediction by the unit 510, the number of consecutive reference position IDs is increased, and when all the prediction data are not predicted correctly, the number of consecutive reference position IDs that have been counted is output to the selection unit 540.
As illustrated in FIGS. 6B and 6C, the code generation unit 550 generates each prediction data (a plurality of prediction data generated by the position-dependent prediction unit 500 and the independent prediction unit 510). Prediction data) and a code are associated with each other, and a code corresponding to the prediction data whose pixel value matches the pixel of interest X is output. The code associated with each prediction data is, for example, an entropy code set in accordance with the prediction hit rate, and has a code length in accordance with the hit rate.

  In addition, the code generation unit 550 is counted by the run counting unit 536 when the pixel values continuously match at the same reference position, or when the prediction by the independent prediction unit 510 continues to hit. The sequence number is encoded. Thereby, the code amount is reduced. In this way, as illustrated in FIG. 6D, the encoding program 5, when any prediction data matches the pixel value of the target pixel, and a code corresponding to the prediction data, and the prediction If the number of consecutive hits in the data is encoded and no prediction data matches the pixel value of the target pixel, the difference between the pixel value of the predetermined reference position and the pixel value of the target pixel X (prediction Error value).

FIG. 7 is a flowchart of the encoding process (S10) by the encoding program 5 (FIG. 4).
As shown in FIG. 7, in step 100 (S100), the encoding program 5 sets the target pixel X in order from the input image data.
The target pixel X in this example is selected in the main scanning direction in order from the pixel at the upper left end of the input image, and when it is selected up to the right end of the main scanning line, it then moves to the main scanning line below the sub scanning direction. The main scanning lines are selected in order from the left end.

In step 110 (S110), the position-dependent prediction unit 500 (FIG. 4) uses the pixel values of the reference positions A to D corresponding to the selected target pixel X as prediction data, and sets the prediction data and the target pixel X. If these pixel values match each other, the reference position ID corresponding to the reference position is output to the run counter 530, and any prediction data is the pixel value of the target pixel X. Is not matched, the fact that they did not match is output to the independent prediction unit 510 and the run counting unit 530.
The independent prediction unit 510 selects one pixel value as prediction data from the pixel values stored as candidate values, and compares the selected prediction data with the pixel value of the target pixel X. When these pixel values match, the reference position ID corresponding to this independent prediction unit 510 is output to the run counting unit 530, and when these pixel values do not match, they match. The fact that there was no output is output to the run counter 530.
Further, the prediction error calculation unit 520 calculates a difference between the pixel value of the target pixel X and the pixel value of the reference position A, and outputs the calculated difference to the selection unit 540 as a prediction error.

  In step 130 (S130), the encoding program 5 outputs a message indicating that there is no match from the position-dependent prediction unit 500 and a message indicating that there is no match from the independent prediction unit 510. When the process proceeds to step S140 and the reference position ID is output from the position-dependent prediction unit 500 or the non-dependence prediction unit 510, the process proceeds to step S140.

In step 140 (S140), the run counting unit 530 (FIG. 4) sets the reference position ID based on the reference position ID input from the position-dependent prediction unit 500 and / or the non-dependent prediction unit 510. The corresponding count value is incremented by one.
Note that the encoding program 5 returns to S100 to perform processing for the next pixel.

In step 150 (S150), the run counting unit 530 receives the prediction data from the position-dependent prediction unit 500 and the independent prediction unit 510 based on the comparison result (prediction result) between the position-dependent prediction unit 500 and the independent prediction unit 510. When it is detected that none of them matches the pixel value of the target pixel X, the count value corresponding to each reference position ID is output to the selection unit 540.
When the count value of each reference position ID is input from the run counter 530, the selection unit 540 calculates the longest continuous number of the reference position ID based on the input count value, and calculates the calculated longest continuous number and The reference position ID is output to the code generation unit 550.
Thereafter, the selection unit 540 outputs the latest prediction error input from the prediction error calculation unit 520 (that is, the prediction error related to the target pixel X for which all the prediction data did not hit) to the code generation unit 550.

  In step 160 (S160), the code generation unit 550 (FIG. 4) encodes the reference position ID, the continuous number, and the prediction error that are sequentially input from the selection unit 540, and converts the code data into the communication device 22 (FIG. 3) or The data is output to the recording device 24 (FIG. 3).

  In step 170 (S170), the independent prediction unit 510 registers the pixel value of the target pixel X as a prediction data candidate. That is, the non-dependent prediction unit 510 of the present example uses the target pixel X on the condition that none of the prediction data from the position-dependent prediction unit 500 and the non-dependent prediction unit 510 matches the pixel value of the target pixel X. Are stored as new candidates for prediction data.

  In step 180 (S180), the encoding program 5 determines whether or not the encoding process has been completed for all the pixels of the input image data. If there are unprocessed pixels, the process of S100 is performed. Returning, the process for the next pixel is performed, and in other cases, the encoding process (S10) is terminated.

FIG. 8 is a flowchart for explaining the prediction process (S110a) by the independent prediction unit 510 (FIGS. 4 and 5) in more detail. That is, the main prediction process (S110a) corresponds to a part performed by the independent prediction unit 510 in the pixel value prediction process (S110) shown in FIG.
As shown in FIG. 8, in step 112 (S112), the candidate value selection unit 516 (FIG. 5) displays the pixel value at the reference position A (for example, the pixel value at the reference position A notified from the position-dependent prediction unit 500). And the first candidate value registered in the candidate value storage unit 514.

  In step 114 (S114), when the pixel value at the reference position A matches the first candidate value, the non-dependent prediction unit 510 (FIG. 5) proceeds to the process at S118, and the pixel value at the reference position A When the first candidate value does not match, the process proceeds to S116.

  In step 116 (S116), the candidate value selection unit 516 selects the first candidate value registered in the candidate value storage unit 514 as prediction data, and outputs the selected first candidate value to the coincidence determination unit 518. To do.

In step 118 (S118), the candidate value selection unit 516 (FIG. 5) selects the second candidate value registered in the candidate value storage unit 514 as prediction data, and determines whether the selected second candidate value matches. To the unit 518.
That is, when the first candidate value does not match the pixel value at the reference position A, the candidate value selection unit 516 of this example selects the first candidate value as the prediction data as it is, and the first candidate value is the reference position A. If the pixel value matches, the second candidate value is selected.

In step 120 (S120), the coincidence determination unit 518 compares the prediction data input from the candidate value selection unit 516 with the pixel value of the target pixel X.
In step 122 (S122), the coincidence determination unit 518 corresponds to the independent prediction unit when the prediction data input from the candidate value selection unit 516 and the pixel value of the target pixel X match. The reference position ID is output to the run counter 530 (FIG. 4), and when these pixel values do not match, the fact that they do not match is output to the run counter 530.

FIG. 9 is a flowchart for explaining in more detail the candidate value registration process (S170) by the independent prediction unit 510 (FIGS. 4 and 5).
As shown in FIG. 9, in step 172 (S172), the registration control unit 512 (FIG. 5) determines whether or not the pixel value of the target pixel X is a pixel value that matches the registration prohibition condition.
When the pixel value of the target pixel X matches the registration prohibition condition, the independent prediction unit 510 prohibits registration of the pixel value of the target pixel X, and ends the candidate value registration process (S170) as it is. When the pixel value of the pixel X does not match the registration prohibition condition, the process proceeds to S174.

  In step 174 (S174), the registration control unit 512 deletes the first candidate value registered in the candidate value storage unit 514 and raises the registered second candidate value to the first candidate value.

  In step 176 (S176), the registration control unit 512 registers the pixel value of the target pixel X in the candidate value storage unit 514 as the second candidate value.

  As described above, the encoding program 5 in the present embodiment uses the position-dependent prediction unit 500 that depends on the relative position to the target pixel X and the independent prediction unit 510 that does not depend on the relative position to the target pixel X. The pixel value of the pixel X is predicted, and the prediction result (whether or not the prediction is correct) is encoded.

[Decryption program]
Next, a method for decoding the encoded data encoded as described above will be described.
FIG. 10 is a diagram illustrating a functional configuration of the decryption program 6 that is executed by the control device 21 (FIG. 3) and implements the decryption method according to the present invention.
As illustrated in FIG. 10, the decoding program 6 includes a code analysis unit 600, a pixel value reference unit 610, a difference processing unit 620, a decoded value storage unit 630, a data selection unit 640, and a data output unit 650.

In the decoding program 6, the code analysis unit 600 is similar to those illustrated in FIGS. 6B and 6C, the code and the reference position ID (reference positions A to D or independent prediction unit). Are correlated with each other, and the input code data is decoded into a reference position ID.
In addition, the code analysis unit 600 also decodes the number of consecutive reference position IDs and numerical values such as prediction errors based on the input code data.
The reference position ID (corresponding to the reference positions A to D) decoded by the code analysis unit 600 and the continuous number thereof are output to the pixel value reference unit 610. Further, the reference position ID (corresponding to the independent prediction unit) decoded by the code analysis unit 600 and the number of continuous positions thereof are output to the data selection unit 640. Further, the prediction error decoded by the code analysis unit 600 is output to the difference processing unit 620.

  Based on the reference position ID input from the code analysis unit 600, the pixel value reference unit 610 refers to the reference position corresponding to the reference position ID, reads the pixel value, and inputs the read pixel value. The data is output to the data output unit 650 by repeating the number of consecutive times.

  The difference processing unit 620 adds the prediction error input from the code analysis unit 600 and the predetermined prediction data (the pixel value at the reference position A), and sends the sum to the decoded value storage unit 630 and the data output unit 650. Output.

The decoded value storage unit 630 stores the sum value (that is, the pixel value decoded using the prediction error) input from the difference processing unit 620.
The decoded value storage unit 630 of this example has an upper limit of the number of entries that can be stored (same as the encoding program 5), and among the total values input from the difference processing unit 620, the latest total value is the second. Stored as a registered value, and the total value input immediately before is stored as the first registered value.

The data selection unit 640 selects from among the total values (pixel values) stored in the decoded value storage unit 630 according to the reference position ID (corresponding to the independent prediction unit) input from the code analysis unit 600. , Any one pixel value is selected, and the selected pixel value is output to the data output unit 650 by repeating the input continuous number (the continuous number of the reference position ID).
When the first registered value stored in the decoded value storage unit 630 does not match the pixel value decoded immediately before (that is, the pixel value at the reference position A), the data selection unit 640 of this example When the first registered value is selected, and the first registered value stored in the decoded value storage unit 630 matches the pixel value decoded immediately before, the second registered value is selected and data output is performed. To the unit 650.

  The data output unit 650 collects pixel values sequentially input from the pixel value reference unit 610, the difference processing unit 620, and the data selection unit 640 into one data file (image data), or the communication device 22 (FIG. 3) or recording. Output to the device 24 (FIG. 3).

FIG. 11 is a flowchart of the decrypting process (S20) by the decrypting program 6 (FIG. 10).
As shown in FIG. 11, in step 200 (S200), the code analysis unit 600 (FIG. 10) sequentially decodes input code data to generate a reference position ID and the number of continuous positions or a prediction error. .

  In step 202 (S202), when the reference position ID corresponding to any of the reference positions A to D is decoded, the code analysis unit 600 sends the reference position ID and the number of consecutive positions to the pixel value reference unit 610. If the prediction error is decoded, the prediction error is output to the difference processing unit 620, and the process proceeds to S208, where the reference position corresponding to the independent prediction unit is output. When the ID is decrypted, this reference position ID and the number of continuous positions are output to the data selection unit 640, and the process proceeds to S212.

In step 204 (S204), the pixel value reference unit 610 (FIG. 10) reads out and reads out the pixel value of the reference position corresponding to the reference position ID based on the reference position ID input from the code analysis unit 600. The obtained pixel value is output to the data output unit 650 as the pixel value of the target pixel X.
In step 206 (S206), the pixel value reference unit 610 determines whether or not the process of S204 has been repeated for the continuous number input from the code analysis unit 600. If the position is shifted by one in the main scanning direction and the process returns to S204, and the process of S204 is repeated for the number of consecutive times, the process proceeds to S220.

In step 208 (S208), the difference processing unit 620 (FIG. 10) adds the prediction error input from the code analysis unit 600 and the predetermined prediction data (the pixel value at the reference position A), and this sum is obtained. The pixel value of the target pixel X is output to the data output unit 650. If the reference pixel corresponding to the reference position A does not actually exist because the target pixel X corresponds to the left end of the image, the difference processing unit 620 adds the predetermined pixel value and the prediction error and outputs the sum. To do.
In step 210 (S210), the difference processing unit 620 registers the sum of the prediction error and the prediction data in the decoded value storage unit 630 as a second registered value. In this case, the decoded value storage unit 630 raises the already registered second registered value to the first registered value before newly registering the second registered value.

In step 212 (S212), the data selection unit 640 (FIG. 10) is stored in the decoded value storage unit 630 according to the reference position ID (corresponding to the independent prediction unit) input from the code analysis unit 600. The first registered value (pixel value) is read, and the read first registered value is compared with the pixel value decoded immediately before (that is, the pixel value at the reference position A).
The data selection unit 640 proceeds to the process of S214 when these values match, and proceeds to the process of S216 when these values do not match.
In step 214 (S214), the data selection unit 640 reads the second registered value from the decoded value storage unit 630 and outputs the read second registered value as the pixel value of the pixel of interest X to the data output unit 650. To do.
In step 216 (S216), the data selection unit 640 outputs the read first registration value to the data output unit 650 as the pixel value of the target pixel X.
In step 218 (S218), the data selection unit 640 determines whether or not the processes of S212 to S216 have been repeated for the number of continuous input input from the code analysis unit 600, and the above-described S212 to S216 up to the input continuous number. If the process of S212 is not repeated, the process returns to the process of S212, the pixel value of the next pixel of interest X is output, and the process of S212 to S216 is repeated for the input continuous number, the process proceeds to S220. To do.

In step 220 (S220), the data output unit 650 (FIG. 10) sequentially arranges the pixel values input from the pixel value reference unit 610, the difference processing unit 620, or the data selection unit 640, and the recording device 24 (FIG. 3). ) Etc.
When the decoding program 6 determines that the decoding process has been completed for all code data, the decoding program 6 ends the decoding process (S20), and if it is determined that there is code data that has not been decoded, the process of S200 Returning to FIG. 4, the next code data is decoded.

  Thus, the decoding program 6 of this example decodes the code data generated by the encoding program 5 (FIG. 4).

  As described above, the image processing apparatus 2 according to the present embodiment predicts the pixel value of the target pixel X using the pixel value at the reference position corresponding to the position of the target pixel X, and when this prediction is lost. The pixel value of the pixel of interest X is independently stored as prediction data candidates, and the pixel value of the pixel of interest X is predicted using these candidates to predict the pixel values of isolated points and the like. It is possible to achieve a higher compression ratio.

[First Modification]
Next, a modification of the above embodiment will be described.
In the above-described embodiment, the form in which the reversible encoding method is applied has been described. In the first modification, a form in which the lossy encoding method is realized will be described.
More specifically, irreversible image processing is performed before the lossless encoding process (S10) described in the above embodiment to achieve a higher compression rate.

FIG. 12 is a diagram illustrating the configuration of the image processing program 7 that performs irreversible image processing.
As illustrated in FIG. 12, the image processing program 7 includes a predicted value providing unit 710, an error determination unit 720, and a pixel value change processing unit 730.
The image processing program 7 is provided in the preceding stage of the encoding program 5 shown in FIG. 4 and performs irreversible image processing on the input image data, and the image data subjected to the irreversible image processing is processed. Output to the encoding program 5.
The computer apparatus in which the image processing program 7 is installed is an example of the data processing apparatus according to the present invention.

In the image processing program 7, the prediction value providing unit 710 generates prediction data for the attention area based on the input image data, and provides the generated prediction data to the error determination unit 720.
The prediction value providing unit 710 of this example generates prediction data for the target pixel X by the same method as the position dependent prediction unit 500 and the independent prediction unit 510 (FIG. 4) provided in the encoding program 5.
As described above, the image processing program 7 corresponds to the predictive encoding process performed by the encoding program 5 at the subsequent stage, and reduces the code amount in cooperation with the encoding program 5.

The error determination unit 720 compares the attention area of the input image data with the prediction data of the attention area generated by the prediction value providing unit 710 and determines whether or not to change the data value of the attention area. judge.
More specifically, the error determination unit 720 calculates a difference between the data value of the attention area and the prediction data of the attention area, and determines whether or not the calculated difference is within a predetermined allowable range. If it is within the allowable range, it is determined that the data value can be changed, and if it exceeds the allowable range, the change of the gradation value is prohibited.
The error determination unit 720 in this example is a difference value between the pixel value of the target pixel X and the prediction data (prediction data generated by the same method as the position-dependent prediction unit 500 and the independent prediction unit 510) for the target pixel X. Is calculated for each prediction data, and when the difference value calculated for any prediction data is within the allowable range, the pixel value of the target pixel X is allowed to be replaced with the prediction data, and any prediction data is When the difference value of the data is also outside the allowable range, the change of the pixel value of the target pixel X is prohibited.

The pixel value change processing unit 730 changes the data value of the attention area according to the determination result by the error determination unit 720.
More specifically, the pixel value change processing unit 730 pays attention so that the accuracy of prediction by the encoding program 5 (FIG. 4) is improved when the data determination is permitted by the error determination unit 720. When the data value of the area is changed and the change of the gradation value is prohibited by the error determination unit 720, the input data value of the attention area is output as it is.
The pixel value change processing unit 730 of this example replaces the pixel value of the target pixel X with prediction data having the smallest difference when the error determination unit 720 permits the change of the pixel value, and the error determination unit 720 When the change of the pixel value is prohibited for all the prediction data, the pixel value of the target pixel X is output to the encoding program 5 as it is.

FIG. 13 is a diagram for explaining the configuration of the predicted value providing unit 710 (FIG. 12) in more detail.
As illustrated in FIG. 13, the predicted value providing unit 710 includes a pixel value reference unit 712, a registration control unit 714, a candidate value storage unit 716, and a candidate value selection unit 718. Note that the pixel value reference unit 712 is a block that generates prediction data by the same method as the position-dependent prediction unit 500 illustrated in FIG. 4, and includes a registration control unit 714, a candidate value storage unit 716, and a candidate value selection unit 718. The set is a block that generates prediction data by the same method as the independent prediction unit 510 illustrated in FIG.

  The pixel value reference unit 712 refers to at least one of the reference positions A to D referred to by the position-dependent prediction unit 500 illustrated in FIG. 4, and uses the pixel value at the reference position as prediction data as an error determination unit 720. (FIG. 12).

The registration control unit 714 corresponds to the registration control unit 512 illustrated in FIG. 5, selects partial data to be registered as a candidate for prediction data, and registers the selected partial data (pixel value) in the candidate value storage unit 716. To do.
More specifically, the registration control unit 714 determines the pixel value of the target pixel X as a candidate value on the condition that any prediction data is determined not to match the pixel value of the target pixel X by the error determination unit 720. Register in the storage unit 716.
The registration control unit 714 of the present example only determines the pixel value of the target pixel X when the error determination unit 720 determines that the differences between the respective prediction data and the pixel value of the target pixel X are all outside the allowable range. Is registered in the candidate value storage unit 716.

  The candidate value storage unit 716 corresponds to the candidate value storage unit 514 illustrated in FIG. 5, and stores the pixel value registered by the registration control unit 714 as a candidate value of prediction data.

The candidate value selection unit 718 corresponds to the candidate value selection unit 516 illustrated in FIG. 5 and is a candidate value stored in the candidate value storage unit 716 (in this example, the first candidate value and the second candidate value). Then, one of the candidate values is selected, and the selected candidate value is output as prediction data to the error determination unit 720 (FIG. 12).
More specifically, the candidate value selection unit 718 selects candidate values whose values do not match the prediction data generated by the pixel value reference unit 712 from among the candidate values stored in the candidate value storage unit 716. The selected candidate value is output as prediction data.

  The prediction data output from the pixel value reference unit 712 and the prediction data output from the candidate value selection unit 718 are calculated by the error determination unit 720 as a difference from the pixel value of the target pixel X, and each difference ( It is evaluated whether or not (error) is within an acceptable range.

FIG. 14 is a flowchart of the lossy encoding process (S30) realized by the image processing program 7 (FIG. 12) and the encoding program 5 (FIG. 4).
As shown in FIG. 14, in step 300 (S300), the image processing program 7 sets the target pixel X in order from the input image data.
The pixel value reference unit 712 (FIG. 13) provided in the prediction unit providing unit 710 (FIGS. 12 and 13) refers to the reference positions A to D corresponding to the position of the target pixel X, and these reference positions A to D. And the plurality of read pixel values are output as prediction data to the error determination unit 720 (FIG. 12).
In addition, the pixel value reference unit 712 notifies the candidate value selection unit 718 (FIG. 13) of the pixel value at the reference position A.

  In step 302 (S302), the candidate value selection unit 718 (FIG. 13) displays the pixel value at the reference position A (that is, the pixel value at the reference position A notified from the pixel value reference unit 712) and the candidate value storage unit 716. Is compared with the first candidate value registered.

  In step 304 (S304), when the pixel value at the reference position A matches the first candidate value, the candidate value selection unit 718 proceeds to the process of S308, and the pixel value at the reference position A and the first candidate value are determined. Is not matched, the process proceeds to S306.

  In step 306 (S306), the candidate value selection unit 718 selects the first candidate value registered in the candidate value storage unit 716 as prediction data, and performs error determination on the selected first candidate value (prediction data). It outputs to the part 720 (FIG. 12).

In step 308 (S308), the candidate value selection unit 718 (FIG. 13) selects the second candidate value registered in the candidate value storage unit 716 as prediction data, and selects the selected second candidate value (prediction data). ) Is output to the error determination unit 720 (FIG. 12).
That is, when the first candidate value does not match the pixel value at the reference position A, the candidate value selection unit 718 of this example selects the first candidate value as the prediction data as it is, and the first candidate value is the reference position A. If the pixel value matches, the second candidate value is selected.

In step 310 (S310), the error determination unit 720 (FIG. 12) determines each of the plurality of prediction data input from the prediction value providing unit 710 (that is, the pixel value reference unit 712 and the candidate value selection unit 718), and the target pixel. The difference from the pixel value of X is calculated.
In step 312 (S312), the error determination unit 720 determines that any of the plurality of pieces of prediction data input from the prediction value providing unit 710 has a difference from the pixel value of the target pixel X within a predetermined allowable range. The process proceeds to S314, and the process proceeds to S318 when the difference between the pixel value of the target pixel X is outside the predetermined allowable range for all of the plurality of prediction data input from the predicted value providing unit 710. To do.
That is, the image processing program 7 shifts to the pixel value changing process of the target pixel X when the difference between any prediction data and the pixel value of the target pixel X is within the allowable range, and the prediction data and the target pixel If any difference between the pixel value of X and the pixel value is outside the allowable range, the process shifts to a candidate value update process registered in the candidate value storage unit 514.

In step 314 (S314), the error determination unit 720 (FIG. 12) selects the prediction data to be applied from the prediction data determined that the difference from the target pixel X is within the allowable range, and the pixel value The change processing unit 730 is notified.
For example, the error determination unit 720 selects prediction data having the smallest difference from the pixel value of the target pixel X as prediction data to be applied. Note that the error determination unit 720 may select prediction data to be applied according to a predetermined priority order.

In step 316 (S316), the pixel value change processing unit 730 (FIG. 12) replaces the pixel value of the target pixel X with the prediction data notified from the error determination unit 720, and the pixel value of the target pixel X after replacement. Is output to the encoding program 5 (FIG. 4).
That is, the image processing program 7 sets the pixel value of the target pixel X to prediction data in which the difference from the target pixel X is within an allowable range (that is, a data value that matches the prediction data generated in the encoding program 5). By replacing with, the accuracy of prediction processing by the encoding program 5 is improved, and a higher compression rate is realized. Further, by setting an appropriate allowable range, it is possible to suppress image quality degradation caused by replacing the pixel value of the target pixel X with the prediction data within a certain range.

In step 318 (S318), the error determination unit 720 (FIG. 12) indicates that the difference between the pixel value of the target pixel X and the prediction data is outside the allowable range, and the predicted value providing unit 710 and the pixel value changing process. Notification to the unit 730.
In response to the notification from the error determination unit 720, the pixel value change processing unit 730 outputs the input pixel value of the target pixel X to the encoding program 5 (FIG. 4) as it is.
Further, the registration control unit 714 (FIG. 13) of the predicted value providing unit 710 sets the second candidate value registered in the candidate value storage unit 716 as the first candidate value in response to the notification from the error determination unit 720. Raise it.
In step 320 (S320), the registration control unit 714 registers the pixel value of the target pixel X in the candidate value storage unit 716 as the second candidate value.

  In step 322 (S322), the image processing program 7 (FIG. 12) determines whether or not the processing has been completed for all the pixels of the input image data, and the processing from S300 to S320 has been completed for all the pixels. In this case, the process proceeds to S10, and when there is an unprocessed pixel, the process returns to S300 and the next target pixel X is set.

  In step 10 (S10), the encoding program 5 (FIG. 4) uses the encoding process described with reference to FIG. 7 for the image data input from the image processing program 7 (that is, the pixel value change processing unit 730). Encode with

  As described above, the image processing apparatus 2 according to the present modified example improves the prediction accuracy of the encoding program 5 (FIG. 4) by irreversible processing (pixel value replacement) in the image processing program 7 (FIG. 12). To achieve a higher compression ratio.

[Other variations]
In the above embodiment, the position-dependent prediction unit 500 generates prediction data with reference to a plurality of reference positions A to D whose relative positions with respect to the target pixel X are predetermined, but the present invention is not limited to this. For example, the periodicity of the input image data may be determined, and the reference position may be determined according to the determined periodicity.
In this case, since the position-dependent prediction unit 500 can use the pixel value at the reference position according to the periodicity of the image as the prediction data, the image data having the periodicity can be encoded more efficiently. .

It is a figure explaining the encoding system which encodes input data, changing a data dictionary dynamically, (A) explains the encoding system using the data dictionary which slides according to an attention area, ( B) describes an encoding method having a data dictionary in a plurality of directions with respect to a region of interest. 4A and 4B are diagrams illustrating input images, where FIG. 5A illustrates an input image including lines in the sub-scanning direction, and FIG. 5B illustrates an input image including a dither pattern. It is a figure which illustrates the hardware constitutions of the image processing apparatus 2 to which the encoding method and decoding method concerning this invention are applied centering on the control apparatus 21. FIG. It is a figure which illustrates the functional structure of the encoding program 5 which is performed by the control apparatus 21 (FIG. 3) and implement | achieves the encoding method concerning this invention. It is a figure explaining the structure of the non-dependent prediction part 510 (FIG. 4) in detail. It is a figure explaining the encoding process performed by the encoding program 4 (FIG. 4), (A) illustrates the reference position referred by the position dependence prediction part 500, (B) is each reference position. (C) illustrates a code associated with the independent prediction unit 510, and (D) illustrates code data generated by the code generation unit 550. It is a flowchart of the encoding process (S10) by the encoding program 5 (FIG. 4). It is a flowchart explaining the prediction process (S110a) by the non-dependent prediction part 510 (FIG. 4, FIG. 5) in detail. It is a flowchart explaining in more detail the candidate value registration process (S170) by the non-dependent prediction part 510 (FIG. 4, FIG. 5). It is a figure which illustrates the functional structure of the decoding program 6 which is performed by the control apparatus 21 (FIG. 3) and implement | achieves the decoding method concerning this invention. It is a flowchart of the decoding process (S20) by the decoding program 6 (FIG. 10). It is a figure explaining the structure of the image processing program 7 which performs an irreversible image process. It is a figure explaining the structure of the predicted value provision part 710 (FIG. 12) in detail. It is a flowchart of the irreversible encoding process (S30) implement | achieved by the image processing program 7 (FIG. 12) and the encoding program 5 (FIG. 4).

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Image processing apparatus 5 ... Coding program 500 ... Position dependence prediction part 510 ... Independent prediction part 512 ... Registration control part 514 ... Candidate value storage part 516 ... Candidate Value selection unit 518 ... Match determination unit 520 ... Prediction error calculation unit 530 ... Run counting unit 540 ... Selection unit 550 ... Code generation unit 6 ... Decoding program 600 ... Code Analysis unit 610 ... Pixel value reference unit 620 ... Difference processing unit 630 ... Decoded value storage unit 640 ... Data selection unit 650 ... Data output unit 7 ... Image processing program 710 ... Predicted value providing unit 712 ... Pixel value reference unit 714 ... Registration control unit 716 ... Candidate value storage unit 718 ... Candidate value selection unit 720 ... Error determination unit 730 ... Pixel value change processing Part

Claims (10)

First prediction means for predicting target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of the target region to be encoded;
Registration determination means for determining that the target portion data should be registered on condition that the predicted data predicted by the first prediction unit and the target portion data do not match;
Data storage means for storing the attention partial data determined to be registered by the registration determination means;
Second predicting means for predicting target partial data to be encoded using any target partial data stored in the data storage means;
The prediction result by the first prediction means, and, based on the prediction result by the second prediction unit, the encoding device having a code generating means for generating code data of the target partial data. A prediction error generating unit that generates a difference between the attention partial data and the prediction data predicted by the first prediction unit as a prediction error;
The code generation unit generates the prediction error when the prediction data predicted by the first prediction unit and the prediction data predicted by the second prediction unit do not match the target partial data. Based on the prediction error generated by the means, generate code data of this attention partial data,
The encoding apparatus according to claim 1, wherein the registration determination unit determines that the target partial data should be registered on the condition that code data is generated based on the prediction error. The second predicting unit selects at least target portion data that does not match the predicted data predicted by the first predictor from the target portion data stored in the data storage unit, and encodes the target portion data. The encoding apparatus according to claim 1, wherein the encoding apparatus is used for prediction of target partial data to be processed. The encoding apparatus according to any one of claims 1 to 3, wherein the registration determination unit determines that the target partial data having a predetermined data value is the target partial data that should not be registered. First preliminary prediction means for predicting target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of the target region to be encoded;
Preliminary data storage means for storing the target portion data on the condition that the prediction data predicted by the first preliminary prediction unit and the target portion data do not match,
Second preliminary prediction means for predicting target partial data to be encoded using any target partial data stored in the preliminary data storage means;
The first preliminary prediction means prediction data predicted by, and for the prediction data predicted by the second preliminary prediction means, and an error evaluating means for evaluating the difference between the target partial data to be encoded,
According to the evaluation result by the error evaluation unit, the target partial data to be encoded is predicted data predicted by the first preliminary prediction unit, or predicted data predicted by the second preliminary prediction unit. Data replacement means for replacement with,
Using at least a prediction method applied by the first preliminary prediction unit and a prediction method applied by the second preliminary prediction unit, at least a part of the target partial data is selected by the data replacement unit. A predictive encoding means for predictively encoding the data replaced with the predictive data. The encoding device according to any one of claims 1 to 5, wherein the target partial data to be encoded is image data corresponding to a part of an image. First prediction means for predicting target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of the target region to be encoded;
Data storage means for storing the target portion data on condition that the predicted data predicted by the first prediction unit and the target portion data do not match;
Second predicting means for predicting target partial data to be encoded using any target partial data stored in the data storage means;
The first prediction data predicted by the prediction means, and, the prediction data predicted by said second prediction means, and an error evaluating means for evaluating the difference between the target partial data to be encoded,
Depending on the evaluation result of the error evaluating means, the target partial data to be encoded, predictive data predicted by said first prediction means, and, substituted with prediction data predicted by said second prediction means A data processing device. Code data obtained by encoding the prediction data of the target portion data predicted using the image data of the reference region at a predetermined relative position with respect to the image data of the target region, and the target portion data that does not match the prediction data Decoding means for decoding the encoded data of
A data reference means for identifying a reference position from the code data decoded by the decoding means, reading reference data corresponding to the reference position, and generating attention partial data based on the read reference data;
Difference processing means for generating the target partial data based on the difference data included in the code data decoded by the decoding means;
Storage means for storing the partial data of interest generated by the difference processing means;
A decoding apparatus comprising: data selecting means for selecting any one of the attention part data from the attention part data stored in the storage means according to the reference position specified by the data reference means. Predicting target partial data to be encoded using image data of a reference region at a predetermined relative position with respect to image data of the target region to be encoded;
Registering the target part data as a prediction candidate on the condition that the predicted data predicted and the target part data do not match,
Predicting target partial data to be encoded using any of the target partial data registered as the prediction candidates;
Wherein the predetermined relative position predicted predicted result using the image data of the reference region in the, and, on the basis of the prediction candidate of the target partial data predicted predicted results using the code data of the target partial data A program that causes a computer to execute the generating step. Code data obtained by encoding the prediction data of the target portion data predicted using the image data of the reference region at a predetermined relative position with respect to the image data of the target region, and the target portion data that does not match the prediction data The encoded data of
Identifying a reference position from the decoded code data, reading reference data corresponding to the reference position, and generating attention partial data based on the read reference data;
Generating the partial data of interest when the decoded code data indicates difference data;
Registering the target partial data generated based on the difference data as a prediction candidate;
When the decoded code data indicates any of the prediction candidates, a program for causing a computer to execute any one of the image data items of interest registered as the prediction candidate. .

Images