JP4144600B2 - Image processing apparatus, image processing method, and image display apparatus - Google Patents

Description

  Since the liquid crystal panel is thin and light, it is widely used as a display device such as a television receiver, a computer display device, and a display unit of a portable information terminal. However, since the liquid crystal requires a certain time from application of the driving voltage to reaching a predetermined transmittance, there is a drawback that it cannot cope with a moving image that changes quickly. In order to solve such a problem, when the gradation value changes between frames, a driving method is applied in which an overvoltage is applied to the liquid crystal so that the liquid crystal reaches a predetermined transmittance within one frame (Patent Document 1). ). Specifically, the image data of the previous frame and the image data of the current frame are compared for each pixel, and when the gradation value changes, the correction amount corresponding to the change amount is used as the image data of the current frame. to add. Thus, when the gradation value increases before one frame, a higher driving voltage is applied to the liquid crystal panel, and when the gradation value decreases, a lower voltage than normal is applied.

  In order to implement the above method, a frame memory for outputting the image data of the previous frame is required. In recent years, with an increase in the number of display pixels due to an increase in the size of a liquid crystal panel, it is necessary to increase the capacity of a frame memory. Further, when the number of display pixels increases, the amount of data to be written to and read from the frame memory within a predetermined period (for example, within one frame period) increases, so that the clock frequency for controlling writing and reading is increased to transfer data. There is a need to increase speed. Such an increase in the frame memory and the transfer rate leads to an increase in the cost of the liquid crystal display device.

  In order to solve such a problem, in the image processing circuit for driving liquid crystal described in Patent Document 2, the memory capacity is reduced by encoding the image data and storing it in the frame memory. Further, the decoded image data of the current frame obtained by decoding the encoded image data, and the decoded image data of one frame before obtained by decoding the encoded image data after delaying one frame period By correcting the image data based on the comparison, it is possible to prevent an unnecessary overvoltage from being applied to the liquid crystal due to an encoding / decoding error when a still image is input.

Japanese Patent No. 2616652 JP 2003-202845 A

  In a moving image, a process (a dither process) for generating a halftone in a pseudo manner is performed by controlling a ratio of a frame in which one gradation is added to the least significant bit of image data. In the image processing circuit for driving liquid crystal described in Patent Document 2, the image data is corrected based on the comparison between the decoded image data of the current frame and the decoded image data of the previous frame. When the processed image data is input, the time of the image data detected using the decoded image when the change for one gradation between frames is amplified by the encoding / decoding error Therefore, a problem arises in that unnecessary overvoltage is applied to the liquid crystal when correction processing that is not originally necessary is performed on the image data.

  The present invention has been made in view of the above problems, and in a liquid crystal drive image processing circuit that encodes and decodes image data in order to reduce frame memory capacity, a signal for generating a pseudo gradation is added. Image processing that corrects image data accurately and applies an appropriate correction voltage to the liquid crystal without causing the effects of encoding / decoding errors even when the input image data is input An object is to provide an apparatus.

An image processing apparatus according to the present invention is an image processing apparatus that corrects and outputs image data representing a gradation value of each pixel of an image based on a change in the gradation value of each pixel.
The image of the current frame is divided into a plurality of blocks, and includes a representative value indicating the size of pixel data in each block, and a quantized value obtained by quantizing the pixel data in each block based on the representative value. Encoding means for outputting first encoded image data corresponding to the image of the current frame;
Decoding means for outputting first decoded image data corresponding to the image of the current frame by decoding the first encoded image data;
Delay means for outputting second encoded image data corresponding to an image one frame before the current frame by delaying the first encoded image data for a period corresponding to one frame;
Decoding means for outputting second decoded image data corresponding to an image one frame before the current frame by decoding the second encoded image data;
With reference to the first encoded image data and the second encoded image data, the change amount of the representative value between the image of the current frame and the image of the previous frame, and the quantized value Code data determination means for obtaining a control signal representing a change in pixel data in each block of the current frame based on these change amounts;
One-frame-before-image calculation means for selecting one of the image data of the current frame and the second decoded image data for each pixel and generating one-frame-before-image data based on the control signal;
And image data correction means for correcting the gradation value of the image of the current frame based on the image data of the previous frame and the image data of the current frame.

An image processing method according to the present invention is an image processing method for correcting and outputting image data representing a gradation value of each pixel of an image based on a change in the gradation value of each pixel,
The image of the current frame is divided into a plurality of blocks, and includes a representative value indicating the size of pixel data in each block, and a quantized value obtained by quantizing the pixel data in each block based on the representative value. Outputting the first encoded image data corresponding to the current frame image;
Outputting the first decoded image data corresponding to the image of the current frame by decoding the first encoded image data;
Outputting the second encoded image data corresponding to the image one frame before the current frame by delaying the first encoded image data for a period corresponding to one frame;
Outputting the second decoded image data corresponding to the image one frame before the current frame by decoding the second encoded image data;
With reference to the first encoded image data and the second encoded image data, the change amount of the representative value between the image of the current frame and the image of the previous frame, and the quantized value Generating a control signal representing a change in pixel data in each block of the current frame based on the amount of change,
Selecting one of the current frame image data and the second decoded image data for each pixel based on the control signal to generate one frame previous image data;
And a step of correcting the gradation value of the image of the current frame based on the image data of the previous frame and the image data of the current frame.

According to the image processing device and the image processing method according to the present invention, the first encoded image data and the second encoded image data are referred to, and an image between the current frame image and the previous frame image is referred to. The amount of change in the representative value and the amount of change in the quantized value are obtained, and a control signal indicating the change in pixel data in each block of the current frame is generated based on the amount of change, and the current Since either one of the image data of the frame and the second decoded image data is selected for each pixel and the image data before one frame is generated, the coding is performed even when the image data to which the pseudo gradation signal is added is input. It is possible to apply an appropriate correction voltage to the liquid crystal without being affected by the error of decoding / decoding.

Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating a configuration of a liquid crystal display device including an image processing device according to the present invention. The receiving unit 2 performs processing such as channel selection and demodulation on the video signal input via the input terminal 1, thereby obtaining image data Di1 representing an image for one frame (image of the current frame) as image data. The data is sequentially output to the processing unit 3. The image data processing unit 3 includes an encoding unit 4, a delay unit 5, decoding units 6 and 7, a change amount calculation unit 8, a code data determination unit 9, a one-frame previous image calculation unit 10, and an image data correction unit 11. Composed. The image data processing unit 3 corrects the image data Di1 based on the change in the gradation value, and outputs the corrected image data Dj1 to the display unit 12. The display unit 12 displays an image by applying a predetermined drive voltage specified by the corrected image data Dj1 to the liquid crystal.

Hereinafter, the operation of the image data processing unit 3 will be described.
The encoding unit 4 encodes the image data Di1 using block encoding (BTC) such as FBTC or GBTC, and outputs encoded image data Da1. Specifically, the image data Di1 is divided into a plurality of blocks, and the image data of each block is quantized using a quantization threshold set according to a representative value representing the size of pixel data in the block. Thus, encoded image data Da1 is generated. As this representative value, an average value La1 and a dynamic range Da1 are used. The encoded image data Da1 includes an average value La1 of image data, a dynamic range Lb1, and a quantized value Q of pixel data in each block.

  The delay unit 5 delays the encoded image data Da1 for a period corresponding to one frame, and outputs encoded image data Da0 one frame before. Here, the higher the coding rate (data compression rate) of the image data Di1 in the coding unit 4, the smaller the memory capacity of the delay unit 5 required for delaying the coded image data Da1. .

  The decoding unit 6 outputs decoded image data Db1 corresponding to the image data Di1 by decoding the encoded image data Da1. Further, the decoding unit 7 decodes the encoded image data Da0 delayed by a period corresponding to one frame by the delay unit 5, thereby outputting decoded image data Db0 representing an image one frame before.

  The change amount calculation unit 8 obtains a difference between the decoded image data Db1 corresponding to the image data of the current frame and the decoded image data Db0 corresponding to the image data of the previous frame for each pixel, and the absolute value of the difference Is output as the change amount Dv1. This change amount Dv1 is input to the previous frame image calculation unit 10 together with the image data Di1 and the decoded image data Db0.

  The encoded data determination unit 9 receives the encoded image data Da1 output from the encoding unit 4 and the encoded image data Da0 of the previous frame output from the delay unit 5. The code data determination unit 9 outputs, for each pixel, a control signal Dw1 indicating a moving image region and a still image region in the image of the current frame based on changes in the current frame and the encoded image data Da1 and Da0 one frame before. . That is, the control signal Dw1 = 1 is output for pixels and blocks whose gradation value changes from the previous frame, and the control signal Dw1 = 0 is output for pixels where the gradation value does not change or is small. The

Specifically, the amount of change | La1-La0 | of the average values La0 and La1 and the amount of change | Lb1-Lb0 | of the dynamic ranges Lb0 and Lb1 of the current frame and the previous block are obtained, and these changes are obtained. When the amount exceeds a predetermined threshold (Tha, Thb), the control signal Dw1 = 1 is output for all the pixels of the block. When the control signal Dw1 = 1 is output for all the pixels of the block, the subsequent-one-frame-previous image calculation unit 10 determines a moving image or a still image for each pixel based on the amount of change Dv1 in each pixel. . That is, it is determined that a pixel whose change amount Dv1 exceeds a predetermined threshold (Thv) represents a moving image, and a pixel whose change amount Dv1 is equal to or less than the threshold represents a still image.
On the other hand, when the amount of change | La1-La0 |, | Lb1-Lb0 | is equal to or smaller than the threshold value, a moving image or a still image is discriminated based on the amount of change | Q1-Q0 | of the quantized values Q1 and Q0 in each pixel. . That is, it is determined that a pixel whose change amount | Q1-Q0 | is 0 or 1 represents a still image, outputs a control signal Dw1 = 0, and a pixel whose change amount is greater than 1 is determined as a moving image and controlled. The signal Dw1 = 1 is output.
The control signal Dw1 output from the code data determination unit 9 is input to the previous frame image calculation unit 10.

  The one-frame-previous image calculation unit 10 selects one of the image data Di1 and the decoded image Db0 one frame before for each pixel based on the values of the control signal Dw1 and the change amount Dv1, and sets one-frame-previous image data Dq0. Generate. Specifically, for the pixel with the control signal Dw1 = 0, the image data Di1 is selected as representing a still image, and for the pixel with Dw = 1, the change amount Dv1 is further referred to, and the value of the change amount Dv1 is small. Is selected as the image data Di1 as representing a still image, and the decoded image Db0 is selected as a pixel representing a moving image for a pixel having a large change amount Dv1. The one-frame previous image data Dq0 is input to the image data correction unit 11.

  The image data correction unit 11 designates the liquid crystal by the image data Di1 within one frame period based on the change in the gradation value between one frame obtained by comparing the image data Di1 and the one-frame previous image data Dq0. The image data Di1 is corrected so as to have a predetermined transmittance, and the corrected image data Dj1 is output. FIG. 2 is a diagram showing response characteristics when a driving voltage based on the corrected image data Dj1 is applied to the liquid crystal. 2, (a) is image data Di1, (b) is corrected image data Dj1, and (c) is a diagram showing response characteristics of liquid crystal obtained by applying a drive voltage based on the image data Dj1. In FIG. 2C, a characteristic indicated by a broken line is a response characteristic of the liquid crystal when a driving voltage based on the image data Di1 is applied. When the gradation value increases / decreases as shown in FIG. 2B, the corrected image data Dj1 is generated by adding / subtracting the correction amounts V1 and V2 to / from the image data Di1. By applying a driving voltage based on the corrected image data Dj1 to the liquid crystal, the liquid crystal can reach a predetermined transmittance specified by the image data Di1 within approximately one frame period as shown in FIG. 2C. it can.

3 to 5 are diagrams for explaining a generation process of the previous frame image data Dq0 in the image data processing unit 3. FIG.
Hereinafter, the generation process of the image data Dq0 one frame before will be described in detail with reference to FIGS. In the following description, the threshold value Tha of the average value change amount | La1-La0 |, the threshold value Thb of the dynamic range change amount | Lb1-Lb0 |, and the threshold value Thv of the change amount Dv are Tha = 10 and Thb = 20, respectively. , Thv = 10.

FIG. 3 is a diagram for describing a generation process of the previous frame image data Dq0 when a still image to which a pseudo gradation signal is added by dither processing is input.
FIGS. 3A and 3D show values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. As shown in FIG. 3D, when the pseudo gradation signal is added to the pixel data (b, B) in the image data Di1 of the current frame by the dither processing, the pixel data changes from 59 to 60. ing.
FIGS. 3B and 3E show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 3A and 3D, respectively. As shown in FIG. 3 (b) and FIG. 3 (e), the average La0 = La1 = 60 image data Di0, Di1 shown in FIG. 3 (a) and FIG. 3 (d), the dynamic range Lb0 = Lb1 = 120. The quantized values Q0 and Q1 are obtained with the number of quantization bits being 2 bits.
FIGS. 3C and 3F show the decoded image data Db0 and Db1 obtained by decoding the encoded image data Da0 and Da1 shown in FIGS. 3B and 3E, respectively. Yes.

FIG. 3G shows an actual change amount of the image which is a difference from the image data Di0 and Di1 shown in FIGS. 3A and 3D, and FIG. ) And the amount of change Dv1 of the decoded image data Db0 and Db1 shown in FIG. As shown in FIG. 3G, the actual change amount of the pixel data of (b, B) is 1, but it is shown in FIG. 3H due to the influence of errors generated in the encoding / decoding process. Thus, the change amount Dv1 of the pixel data (b, B) is 40.
FIG. 3I shows an error between the actual change amount shown in FIG. 3G and the change amount Dv1 shown in FIG. It can be seen that a large error occurs in the pixel data in (b, B) to which the pseudo gradation signal is added due to the influence of the encoding / decoding error.

  FIG. 3 (j) shows a control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 3 (b) and 3 (e). As shown in FIGS. 3B and 3E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 0, and the change amount of the dynamic range is | Lb1-Lb0 | = 0. In both cases, the threshold values Tha = 10 and Thb = 20 or less. Also, the amount of change | Q1-Q0 | in the quantized value is 1 for the (B, b) pixel and 0 for the other pixels. Therefore, the code determination unit 9 outputs the control signal Dw1 = 0 for all the pixels.

  FIG. 3 (k) shows the decoded image data Db0 shown in FIG. 3 (c) based on the change amount Dv1 shown in FIG. 3 (h) and the control signal Dw1 shown in FIG. 3 (j). The image data Dq0 one frame before is generated by selecting one of the image data Di1 shown in d) for each pixel. As shown in FIG. 3 (h), for the pixel data of (b, B), the change amount Dv1 exceeds the threshold (Thv = 10), but as shown in FIG. Since the number of pixels is 0, the one-frame-before image calculation unit 10 selects the image data Di1 of the current frame for all the pixels and generates one-frame-before image data Dq0.

  FIG. 3 (l) shows an error between the image data Di0 one frame before shown in FIG. 3 (a) and the image data Dq0 one frame before shown in FIG. 3 (j). As shown in FIG. 3 (l), by selecting the image data Di1 of the current frame as the image data of the previous frame based on the control signal Dw1 and the change amount Dv1, the encoding / decoding error due to the pseudo gradation signal Can be corrected. That is, based on the block average value variation | La1-La0 |, dynamic range variation | Lb1-Lb0 |, and quantization value variation | Q1-Q0 | included in the encoded image data Da0 and Da1. Thus, it is possible to prevent an encoding / decoding error due to dither processing by discriminating the change of the image and the pseudo gradation and selecting the image data Di1 of the current frame when the pseudo gradation is determined.

FIG. 4 is a diagram for explaining the operation of the image data processing unit 3 when a moving image is input.
FIGS. 4A and 4D show values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. Comparing the image data Di0 and Di1 shown in FIG. 4A and FIG. 4D, the pixel data in the B column changes from 0 to 59, the pixel data in the C column changes from 59 to 60, and the D column The pixel data changes from 60 to 0.
FIGS. 4B and 4E respectively show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 4A and 4D. FIG 4 (b) and as shown in FIG. 4 (e), 4 (a) and image data Di0, the average value of Di1 is La0 = La1 = 30 shown in FIG. 4 (d), the dynamic range Lb0 = Lb1 = 60.
4 (c) and 4 (f) show decoded image data Db0 and Db1 obtained by decoding the encoded image data Da0 and Da1 shown in FIGS. 4 (b) and 4 (e), respectively. Yes.

FIG. 4G shows the actual change amount of the image, which is the difference from the image data Di0 and Di1 shown in FIG. 4A and FIG. 4D, and FIG. ) And the amount of change Dv1 of the decoded image data Db0 and Db1 shown in FIG.
FIG. 4 (i) shows an error between the actual change amount shown in FIG. 4 (g) and the change amount Dv1 shown in FIG. 4 (h).

  FIG. 4 (j) shows a control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 4 (b) and 4 (e). As shown in FIGS. 4B and 4E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 0, and the change amount of the dynamic range is | Lb1-Lb0 | = 0. In both cases, the threshold values Tha = 10 and Thb = 20 or less. Also, the amount of change | Q1-Q0 | in the quantization value is 0 for the pixels in the A and C columns, and 3 for the pixels in the B and D columns. Therefore, the code determination unit 9 outputs the control signal Dw1 = 0 for the pixels in the A and C columns, and outputs the control signal Dw1 = 1 for the pixels in the B and D columns.

  FIG. 4 (k) shows the decoded image data Db0 shown in FIG. 4 (c) based on the change amount Dv1 shown in FIG. 4 (h) and the control signal Dw1 shown in FIG. 4 (j). The image data Dq0 one frame before is generated by selecting one of the image data Di1 shown in d) for each pixel. As shown in FIG. 4 (h), the change amount Dv1 is 60 in the B and D columns and exceeds the threshold (Thv = 10), and the control signal Dw1 is A, as shown in FIG. 4 (j). It is 0 for the pixels in the C column and 1 for the pixels in the B and D columns. Therefore, the previous frame image calculation unit 10 selects the current frame image data Di1 for the A and C column pixels, selects the decoded image data Db0 for the B and D column pixels, and sets the previous frame image data Dq0. Generate.

  FIG. 4 (l) shows an error between the image data Di0 one frame before shown in FIG. 4 (a) and the image data Dq0 one frame before shown in FIG. 4 (j). As shown in FIG. 4 (l), by selecting the image data Di1 of the current frame and the decoded image data Db0 for each pixel based on the control signal Dw1 and the change amount Dv1, the previous frame image data Dq0 is accurately obtained. Can be generated. Further, the error shown in FIG. 4 (l) is smaller than the error shown in FIG. 4 (i). That is, it can be seen that the change amount error between the previous frame image data Dq0 and the image data Di0 is smaller than the change amount error Dv1 between the decoded image data Db0 and Db1.

FIG. 5 is a diagram for explaining the operation of the image data processing unit 3 when another moving image is input.
FIGS. 5A and 5D show values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. Comparing the image data Di0 and Di1 shown in FIG. 5A and FIG. 5D, the pixel data in the B column changes from 0 to 59, the pixel data in the C column changes from 59 to 60, and the D column The pixel data of the change from 60 to 120.
FIGS. 5B and 5E show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 5A and 5D, respectively. 5 (b) and as shown in FIG. 5 (e), 5 (a) and 5 image data Di0 to (d), the average value of Di1 is La0 = 30, La1 = 60, the dynamic range Lb0 = 60, Lb1 = 120.
FIGS. 5C and 5F show decoded image data Db0 and Db1 obtained by decoding the encoded image data Da0 and Da1 shown in FIGS. 5B and 5E, respectively. Yes.

FIG. 5G shows the actual change amount of the image which is the difference from the image data Di0 and Di1 shown in FIG. 5A and FIG. 5D, and FIG. ) And the amount of change Dv1 of the decoded image data Db0 and Db1 shown in FIG. 5 (f).
FIG. 5 (i) shows an error between the actual change amount shown in FIG. 5 (g) and the change amount Dv1 shown in FIG. 5 (h).
FIG. 5 (j) shows a control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 5 (b) and 5 (e). As shown in FIGS. 5B and 5E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 30, and the change amount of the dynamic range is | Lb1-Lb0 | = 60. In both cases, since the threshold values Tha = 10 and Thb = 20 are exceeded, the control signal Dw = 1 is output for all the pixels of the block.

FIG. 5 (k) shows the decoded image data Db0 shown in FIG. 5 (c) based on the variation Dv1 shown in FIG. 5 (h) and the control signal Dw1 shown in FIG. 5 (j). The image data Dq0 one frame before is generated by selecting one of the image data Di1 shown in d) for each pixel. As shown in FIG. 5 (h), the change amount Dv1 is 40, 20, 60 in the B, C, and D columns, and exceeds the threshold value (Thv = 10), and as shown in FIG. 5 ( j ). The control signal Dw1 is 1 for all pixels. Therefore, the previous frame image calculation unit 10 selects the current frame image data Di1 for the pixels in the A column, selects the decoded image data Db0 for the pixels in the B, C, and D columns, and sets the previous frame image data Dq0. Generate.

  FIG. 5 (l) shows an error between the image data Di0 one frame before shown in FIG. 5 (a) and the image data Dq0 one frame before shown in FIG. 5 (k). As shown in FIG. 5 (l), when the change amount | La1-La0 | of the average value of the block and the change amount | Lb1-Lb0 | of the dynamic range exceed a predetermined threshold (Tha, Thb), the change amount Dv1 By selecting either the image data Di1 of the current frame or the decoded image data Db0 for each pixel based on the size, the previous frame image data Dq0 can be accurately generated with a small error.

As described above with reference to FIGS. 3 to 5, the average value change amount | La1−La0 |, the dynamic range change amount | Lb1−Lb0 |, and the quantized value change from the encoded image data Da0 and Da1. A quantity | Q1-Q0 | is obtained, and based on these values, a control signal Dw1 for determining whether each pixel represents a moving image or a still image is output, and decoding is performed based on the control signal Dw1 and the change amount Dv1. By selecting and generating one of the pixelated image data Db0 and the image data Di1 for each pixel, the previous frame image data Dq0 can be accurately reproduced. Thereby, even when the image data Di1 to which the pseudo gradation signal is added is input, it is possible to apply an appropriate correction voltage to the liquid crystal without being affected by the encoding / decoding error.

  Note that, as an encoding method in the encoding unit 4, in encoding such as JPEG, JPEG-LS, and JPEG2000 that converts image data into frequency domain data, it is conceivable to use a low frequency component as a representative value of a block. . Such a still image encoding method can be applied even to lossy encoding in which the image data before encoding and the decoded image data do not completely match.

FIG. 6 is a flowchart showing the processing steps of the image data processing unit 3 described above.
First, the image data Di1 is input to the image data processing unit 3 (St1). The encoding unit 4 encodes the input image data Di1 and outputs encoded image data Da1 (St2). The delay unit 5 delays the encoded image data Da1 by one frame period, and outputs encoded image data Da0 one frame before (St3). The decoding unit 7 decodes the encoded image data Da0 and outputs decoded image data Db0 corresponding to the image data Di0 of the previous frame (St4). In parallel with these processes, the decoding unit 6 decodes the encoded image data Da1, and outputs decoded image data Db1 corresponding to the image data Di1 of the current frame (St5).

  The change amount calculation unit 8 calculates a difference between the decoded image data Db0 of the previous frame and the decoded image data Db1 of the current frame for each pixel, and outputs the absolute value of this difference as the change amount Dv1 (St6). . In parallel with this processing, the code data determination unit 9 compares the encoded image data Da0 of the previous frame with the encoded image data Da1 of the current frame, and the amount of change | La1- of the average values La0 and La1 of each block When La0 | and the amount of change | Lb1-Lb0 | of the dynamic ranges Lb0 and Lb1 exceed a predetermined threshold (Tha, Thb), the control signal Dw1 = 1 is output for the entire pixels of the block. On the other hand, when the amount of change | La1-La0 |, | Lb1-Lb0 | is equal to or smaller than the threshold value, the control signal Dw1 = 0 is output for a pixel in which the amount of change | Q1-Q0 | A control signal Dw1 = 1 is output for a pixel whose change amount | Q1-Q0 | is greater than 1 (St7).

  The one-frame-previous image calculation unit 10 selects the decoded image data Db0 as the image data of the previous frame for a pixel in which the change amount Dv1 is greater than a predetermined threshold (Thv) and the control signal Dw1 is 1. For pixels for which the change amount Dv1 is smaller than a predetermined threshold value or the control signal Dw1 is 0, the original image data Di1 is selected as the image data for the previous frame, thereby outputting the previous frame image data Dq0 (St8). ).

The image data correction unit 11 performs predetermined transmission specified by the image data Di1 within one frame period based on a change in the gradation value obtained by comparing the image data Dq0 of the previous frame with the image data Di0. A correction amount required to drive the image at a rate is obtained, the correction amount is used to correct the image data Di1, and the corrected image data Dj1 is output (St9).
The processing of St1 to St9 is performed on each pixel of the image data Di1.

The one-frame previous image data Dq0 may be calculated by the following equation (1).
Dq0 = min (k1, k2) × Db0 + (1-min (k1, k2)) × Di1 Formula (1)
In the above equation (1), k1 and k2 are variables that take values from 0 to 1 according to the amount of change Dv1 and the control signal Dw1, respectively. Note that min (k1, k2) is the smaller value of either k1 or k2.

  FIG. 7 is a diagram showing the relationship between the change amounts Dv1 and k1 and the control signals Dw1 and k2. As shown in FIG. 7A, two threshold values SH0 and SH1 (SH0 <SH1) are set in advance for the change amount Dv1, and when Dv1 <SH0, k1 = 0 and SH0 ≦ Dv1 ≦ SH1. In this case, 0 ≦ k1 ≦ 1, and in the case of Dv1> SH1, k1 = 1. As shown in FIG. 7B, two threshold values SH2 and SH3 (SH2 <SH3) are preset for the control signal Dw1, and when Dw1 <SH1, k2 = 0 and SH2 ≦ Dw1 ≦ SH3. In this case, 0 ≦ k2 ≦ 1, and in the case of Dw1> SH3, k2 = 1.

  As shown in equation (1), when either k1 or k2 is 0, the image data Di1 is selected as the previous frame image data Dq0, and when both k1 and k2 are 1, the decoded image The data Db0 is output as the previous frame image data Dq0. In other cases, the weighted average of the image data Di1 and the decoded image data Db0 is calculated as the previous frame image data Dq0 based on the smaller value of k1 and k2.

  In this way, by using Expression (1), it is possible to obtain ideal one-frame previous image data Dq0 with less error even when the change amount Dv1 and the control signal Dw1 are near the threshold value.

Further, the control signal Dw1 may be calculated by the following equation (2).
Dw1 = kc × (1−max (ka, kb)) + kd × max (ka, kb) (2)
In the above equation (2), ka and kb are variables that take values from 0 to 1 depending on the magnitude of the average value change amount | La1-La0 | and the dynamic range change amount | Lb1-Lb0 |, respectively. is there. Kc is a variable that takes a value of 0 or 1 depending on the magnitude of the change amount | Q1-Q0 | of the quantization value, and kd is a predetermined constant. Note that max (ka, kb) is the larger value of ka or kb.

FIG. 8 is a diagram showing the values of ka, kb, kc, and kd in the above equation (2).
FIG. 8A is a diagram showing the relationship between the change amount | La1-La0 | of the average value and ka. As shown in FIG. 8A, two threshold values SH4 and SH5 (SH4 <SH5) are set in advance for the change amount | La1-La0 | of the average value, and in the case of | La1-La0 | <SH4 Is ka = 0, SH4 ≦ | La1−La0 | ≦ SH5, 0 ≦ ka ≦ 1, and | La1−La0 |> SH5, ka = 1.

  FIG. 8B is a diagram showing the relationship between the dynamic range variation | Lb1-Lb0 | and kb. As shown in FIG. 8B, two threshold values SH6 and SH7 (SH6 <SH7) are preset for the dynamic range change amount | Lb1-Lb0 |, and when | Lb1-Lb0 | <SH6 Is equal to 0 ≦ kb ≦ 1 when kb = 0, SH6 ≦ | Lb1−Lb0 | ≦ SH7, and kb = 1 when | Lb1−Lb0 |> SH7.

  FIGS. 8C and 8D are diagrams respectively showing the relationship between the quantization value change amount | Q1-Q0 | and kc and kd. The variable kc shown in FIG. 8C is determined when the target block is determined to be a still image or an image with small motion, that is, the amount of change in the average value is | La1-La0 | <SH5, Used when the amount of change is | Lb1-Lb0 | <SH7. On the other hand, the constant kd (= 1) shown in FIG. 8D is obtained when the block is determined to be a moving image, that is, when the average value change amount is | La1-La0 | ≧ SH5 or the dynamic range changes. Used when the quantity is | Lb1-Lb0 | ≧ SH7.

  As shown in Expression (2), when both ka and kb are 0, kc having the characteristics shown in FIG. 8C is selected as the control signal Dw1, and either ka or kb is 1. Kd = 1 is selected as the control signal Dw1. In other cases, the weighted average of kc and kd is calculated as the control signal Dw1 based on the larger value of ka and kb.

Embodiment 2. FIG.
In the first embodiment, the image data correction unit 11 calculates a correction amount based on a change in gradation value obtained by comparing the image data Dq0 one frame before and the image data Di0, and generates corrected image data Dj1. However, it is also possible to provide a memory means such as a lookup table, read the correction amount stored in advance, correct the image data Di1, and output the corrected image data Dj1.

  FIG. 9 is a block diagram showing an internal configuration of the image data correction unit 11 according to the present embodiment. The look-up table 11a receives the previous frame image data Dq0 and the image data Di1, and outputs a correction amount Dc1 based on both values.

  FIG. 10 is a schematic diagram illustrating an example of the configuration of the lookup table 11a. Image data Di1 and image data Dq0 one frame before are input as read addresses to the lookup table 11a. When the image data Di1 and the previous frame image data Dq0 are 8-bit image data, 256 × 256 data is stored as the correction amount Dc1 in the lookup table 11a. The look-up table 11a reads out and outputs correction amounts Dc1 = dt (Di1, Dq0) corresponding to the values of the image data Di1 and the one-frame previous image data Dq0. The correction unit 11b adds the correction amount Dc1 output from the lookup table 11a to the image data Di1, and outputs corrected image data Dj1.

  FIG. 11 is a diagram showing an example of the response time of the liquid crystal, where the x-axis is the value of the image data Di1 (gradation value in the current image), and the y-axis is the value of the image data Di0 one frame before (one frame before) The z-axis represents the response time required for the liquid crystal to reach the transmittance corresponding to the gradation value of the image data Di1 from the transmittance corresponding to the gradation value one frame before. . Here, when the gradation value of the current image is 8 bits, there are 256 × 256 combinations of the gradation values of the image data and the image data of the previous frame, and there are 256 × 256 response times. In FIG. 11, the response time corresponding to the combination of gradation values is shown in a simplified manner of 8 × 8.

  FIG. 12 is a diagram showing the value of the correction amount Dc1 added to the image data Di1 so that the liquid crystal has the transmittance specified by the image data Di1 when one frame period elapses. When the gradation value of the image data is 8 bits, there are 256 × 256 correction amounts Dc1 corresponding to combinations of the gradation values of the image data and the image data one frame before. In FIG. 12, the correction amount corresponding to the combination of gradation values is simplified and shown in 8 × 8 ways.

  As shown in FIG. 11, since the response time of the liquid crystal differs depending on the gradation value of the image data and the image data of the previous frame, the lookup table 11a includes both the image data and the image data of the previous frame. 256 × 256 kinds of correction amounts Dc1 corresponding to the gradation values are stored. In particular, the response speed of the liquid crystal is slow when changing from an intermediate gradation (gray) to a high gradation (white) (the reverse or another change may be slow depending on the type of liquid crystal panel or the operation mode). . Accordingly, the response speed is effectively improved by setting a large value for the correction amount dt (Di1, Dq0) corresponding to the image data Dq0 one frame before representing the intermediate gradation and the image data Di1 representing the high gradation. be able to. Further, since the response characteristics of the liquid crystal change depending on the material of the liquid crystal, the electrode shape, the temperature, and the like, the response time according to the characteristics of the liquid crystal can be obtained by using the lookup table 11a having the correction amount Dc1 corresponding to such use conditions. Can be controlled.

  As described above, by using the lookup table 11a storing the correction amount Dc1 obtained in advance, it is possible to reduce the calculation amount when outputting the corrected image data Dj1.

  FIG. 13 is a block diagram showing another internal configuration of the image data correction unit 11 according to the present embodiment. The look-up table 11c shown in FIG. 13 receives the previous frame image data Dq0 and the image data Di1, and outputs corrected image data Dj1 = (Di1, Dq0) based on both values. The look-up table 11c stores corrected image data Dj1 = (Di1, Dq0) obtained by adding 256 × 256 correction amounts Dc1 = (Di1, Dq0) shown in FIG. 12 to the image data Di1. The The corrected image data Dj1 is set not to exceed the displayable gradation range of the display unit 12.

  FIG. 14 is a diagram illustrating an example of the corrected image data Dj1 stored in the lookup table 11c. When the gradation value of the image data is 8 bits, there are 256 × 256 correction amounts Dc1 corresponding to combinations of the gradation values of the image data and the image data one frame before. In FIG. 14, the correction amount corresponding to the combination of gradation values is simplified and shown in 8 × 8 ways.

  In this way, the corrected image data Dj1 obtained in advance is stored in the lookup table 11c, and the corresponding corrected image data Dj1 is output based on the image data Di1 and the one-frame previous image data Dq0. The amount of calculation when outputting Dj1 can be further reduced.

Embodiment 3 FIG.
FIG. 15 is a block diagram showing another configuration of the liquid crystal display device including the image processing device according to the present invention. The image data processing unit 3 of the liquid crystal driving image processing apparatus according to the present embodiment includes an encoding unit 4, a delay unit 5, a decoding unit 7, a code data determination unit 9, a pre-frame image calculation unit 14, and an image. The data correction unit 11 is configured. Components equivalent to those of the image data processing unit 3 shown in FIG.

In the image data processing unit 3 according to the present embodiment, the one-frame previous image calculation unit 14 converts the image data Di1 and the decoded image data Db0 for each pixel based only on the control signal Dw1 output from the code data determination unit 9. To generate the previous frame image data Dq0. That is, the decoded image data Db0 is selected as the image data one frame before for the pixel whose control signal is Dw1 = 1, and the image data Di1 is the image data one frame before for the pixel whose control signal is Dw1 = 0. As a result, the previous frame image data Dq0 is generated. The method for generating the control signal Dw1 is the same as that in the first embodiment.

FIGS. 16-18 is a figure for demonstrating the production | generation process of the 1-frame previous image data Dq0 in the image data process part 3 which concerns on this Embodiment.
Hereinafter, with reference to FIGS. 16 to 18, the generation process of the one-frame previous image data Dq0 according to the present embodiment will be described in detail. In the following description, the threshold value Tha of the average value change amount | La1-La0 | and the threshold value Thb of the dynamic range change amount | Lb1-Lb0 | are Tha = 10 and Thb = 20, respectively.

FIG. 16 is a diagram for describing a generation process of the previous frame image data Dq0 when a still image to which a pseudo gradation signal is added by dither processing is input.
FIGS. 16A and 16D show the values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. As shown in FIG. 16D, when the pseudo gradation signal is added to the pixel data of (b, B) in the image data Di1 of the current frame by the dither processing, the pixel data changes from 59 to 60. ing.
FIGS. 16B and 16E show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 16A and 16D, respectively. As shown in FIG. 16 (b) and FIG. 16 (e), the average value of the image data Di0, Di1 shown in FIG. 16 (a) and FIG. 16 (d) is La0 = La1 = 60, the dynamic range Lb0 = Lb1 = 120.
FIG. 16C shows decoded image data Db0 obtained by decoding the encoded image data Da0 shown in FIG.
FIG. 16F shows an actual change amount of the image which is a difference from the image data Di0 and Di1 shown in FIGS. 16A and 16D.

  FIG. 16G shows a control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 16B and 16E. As shown in FIGS. 16B and 16E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 0, and the change amount of the dynamic range is | Lb1-Lb0 | = 0. In both cases, the threshold values Tha = 10 and Thb = 20 or less. Also, the amount of change | Q1-Q0 | of the quantized value is 1 for the pixel (b, B) and 0 for the other pixels. Therefore, the code determination unit 9 outputs the control signal Dw1 = 0 for all the pixels.

  In FIG. 16 (h), based on the control signal Dw1 shown in FIG. 16 (g), any one of the decoded image data Db0 shown in FIG. 16 (c) and the image data Di1 shown in FIG. Image data Dq0 one frame before that is generated by being selected every time is shown. As shown in FIG. 16G, the control signal Dw1 is 0 for all pixels. Therefore, the previous frame image calculation unit 10 selects the current frame image data Di1 for all the pixels and generates the previous frame image data Dq0.

  FIG. 16 (i) shows an error between the image data Di0 one frame before shown in FIG. 16 (a) and the image data Dq0 one frame before shown in FIG. 16 (j). As shown in FIG. 16 (i), even when the one-frame previous image data Dq0 is generated based only on the control signal Dw1, the encoding / decoding error due to the pseudo gradation signal can be corrected.

FIG. 17 is a diagram for explaining the operation of the image data processing unit 3 when a moving image is input.
FIGS. 17A and 17D show the values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. When comparing the image data Di0 and Di1 shown in FIGS. 17A and 17D, the pixel data of the B column changes from 0 to 59, the pixel data of the C column changes from 59 to 60, and the D column The pixel data changes from 60 to 0.
FIGS. 17B and 17E show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 17A and 17D, respectively. As shown in FIG. 17 (b) and FIG. 17 (e), the average value of the image data Di0, Di1 shown in FIGS. 17 (a) and 17 (d) is La0 = La1 = 30, the dynamic range Lb0 = Lb1 = 60.
FIG. 17C shows decoded image data Db0 obtained by decoding the encoded image data Da0 shown in FIG.
Figure 17 (f) shows the actual change amount of the image which is a difference between the image data Di0, Di1 shown in FIGS. 17 (a) and 17 (d).

  FIG. 17G shows the control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 17B and 17E. As shown in FIGS. 17B and 17E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 0, and the change amount of the dynamic range is | Lb1-Lb0 | = 0. In both cases, the threshold values Tha = 10 and Thb = 20 or less. Also, the amount of change | Q1-Q0 | in the quantization value is 0 for the pixels in the A and C columns, and 3 for the pixels in the B and D columns. Therefore, the code determination unit 9 outputs the control signal Dw1 = 0 for the pixels in the A and C columns, and outputs the control signal Dw1 = 1 for the pixels in the B and D columns.

  FIG. 17H shows, based on the control signal Dw1 shown in FIG. 17G, any one of the decoded image data Db0 shown in FIG. 17C and the image data Di1 shown in FIG. Image data Dq0 one frame before that is generated by being selected every time is shown. As shown in FIG. 17G, the control signal Dw1 is 0 for the pixels in the A and C columns, and 1 for the pixels in the B and D columns. Therefore, the previous frame image calculation unit 10 selects the current frame image data Di1 for the A and C column pixels, selects the decoded image data Db0 for the B and D column pixels, and sets the previous frame image data Dq0. Generate.

  FIG. 17 (i) shows an error between the image data Di0 one frame before shown in FIG. 17 (a) and the image data Dq0 one frame before shown in FIG. 17 (j). As shown in FIG. 17 (i), the image data Di1 of the current frame and the decoded image data Db0 are selected for each pixel based on the control signal Dw1, thereby accurately generating the previous frame image data Dq0. Can do.

FIG. 18 is a diagram for explaining the operation of the image data processing unit 3 when another moving image is input.
FIGS. 18A and 18D show the values of the image data Di0 one frame before and the image data Di1 of the current frame, respectively. Comparing the image data Di0 and Di1 shown in FIG. 18A and FIG. 18D, the pixel data of the B column changes from 0 to 59, the pixel data of the C column changes from 59 to 60, and the D column The pixel data of the change from 60 to 120.
FIGS. 18B and 18E show encoded image data Da0 and Da1 corresponding to the image data Di0 and Di1 shown in FIGS. 18A and 18D, respectively. Figure 18 (b) and as shown in FIG. 18 (e), the image data Di0, the average value of Di1 is La0 = 30, La1 = 60 shown in FIG. 18 (a) and FIG. 18 (d), the dynamic range Lb0 = 60, Lb1 = 120.
FIG. 18C shows decoded image data Db0 obtained by decoding the encoded image data Da0 shown in FIG.
FIG. 18F shows an actual change amount of the image which is a difference from the image data Di0 and Di1 shown in FIGS. 18A and 18B.

FIG. 18G shows the control signal Dw1 output based on the encoded image data Da0 and Da1 shown in FIGS. 18B and 18E. As shown in FIGS. 18B and 18E, the change amount of the average value of the current frame and the previous frame is | La1-La0 | = 30, and the change amount of the dynamic range is | Lb1-Lb0 | = 60. In both cases, since the threshold values Tha = 10 and Thb = 20 are exceeded, the control signal Dw = 1 is output for all the pixels of the block.
FIG. 18H shows, based on the control signal Dw1 shown in FIG. 18G, any one of the decoded image data Db0 shown in FIG. 18C and the image data Di1 shown in FIG. Image data Dq0 one frame before that is generated by being selected every time is shown. Since the control signal Dw1 is 1 for all the pixels as shown in FIG. 18 (g), the one-frame-before image calculation unit 10 selects the decoded image data Db0 for all the pixels, and the one-frame-before image data Dq0 is generated.

  FIG. 18 (i) shows an error between the image data Di0 one frame before shown in FIG. 18 (a) and the image data Dq0 one frame before shown in FIG. 18 (f). As shown in FIG. 18 (i), when the change amount | La1-La0 | of the average value of the block and the change amount | Lb1-Lb0 | of the dynamic range exceed a predetermined threshold (Tha, Thb), the decoded image data By selecting Db0 as the image data of the previous frame, the previous frame of image data Dq0 can be accurately generated with a small error.

  As described above with reference to FIGS. 16 to 18, pseudo gradations can also be obtained by selecting and generating either decoded image data Db0 or image data Di1 for each pixel based on only the control signal Dw1. The previous frame image data Dq0 can be accurately generated without being affected by the encoding / decoding error when the image data Di1 to which the signal is added is input.

FIG. 19 is a flowchart showing the processing steps of the liquid crystal driving image processing unit according to the present embodiment described above.
First, the image data Di1 is input to the image data processing unit 13 (St1). The encoding unit 4 encodes the input image data Di1 and outputs encoded image data Da1 (St2). The delay unit 5 delays the encoded image data Da1 by one frame period, and outputs encoded image data Da0 one frame before (St3). The decoding unit 7 decodes the encoded image data Da0 and outputs decoded image data Db0 corresponding to the image data Di0 of the previous frame (St4). In parallel with this processing, the code data determination unit 9 compares the encoded image data Da0 of the previous frame with the encoded image data Da1 of the current frame, and the amount of change in the average value of each block | La1-La0 | When the change amount | Lb1−Lb0 | of the dynamic ranges Lb0 and Lb1 exceeds a predetermined threshold (Tha, Thb), the control signal Dw1 = 1 is output for all the pixels of the block. On the other hand, when the amount of change | La1-La0 |, | Lb1-Lb0 | is equal to or smaller than the threshold value, the control signal Dw1 = 0 is output for a pixel in which the amount of change | Q1-Q0 | A control signal Dw1 = 1 is output for a pixel having a change amount greater than 1 (St7).

The one-frame-before image calculation unit 10 selects the decoded image data Db0 as the image data one frame before for the pixel for which the control signal Dw1 is 1, and sets the image data Di1 to 1 for the pixel for which the control signal Dw1 is 0. The image data is selected as the image data before the frame and is output as the image data Dq0 before the frame (St18).

The image data correction unit 11 performs predetermined transmission specified by the image data Di1 within one frame period based on a change in the gradation value obtained by comparing the image data Dq0 of the previous frame with the image data Di0. A correction amount required to drive the image at a rate is obtained, the correction amount is used to correct the image data Di1, and the corrected image data Dj1 is output (St9).
The processing of St1 to St18 is performed on each pixel of the image data Di1.

1 is a block diagram showing an embodiment of an image processing apparatus for driving a liquid crystal according to the present invention. It is a figure which shows the response characteristic of a liquid crystal. It is a figure for demonstrating the production | generation process of the image data before 1 frame. It is a figure for demonstrating the production | generation process of the image data before 1 frame. It is a figure for demonstrating the production | generation process of the image data before 1 frame. 3 is a flowchart showing the operation of the image processing apparatus for driving a liquid crystal according to the present invention. It is a figure which shows the characteristic of the variable k1, k2. It is a figure which shows the characteristic of variables ka, kb, kc, and kd. It is a block diagram which shows an example of an internal structure of an image data correction | amendment part. It is a schematic diagram which shows the structure of a lookup table. It is a figure which shows an example of the response speed of a liquid crystal. It is a figure which shows an example of the corrected amount stored in a lookup table. It is a block diagram which shows an example of an internal structure of an image data correction | amendment part. It is a figure which shows an example of the correction | amendment image data stored in a lookup table. It is a block diagram which shows one Embodiment of the image processing part for a liquid crystal drive concerning this invention. It is a figure for demonstrating the production | generation process of the image data before 1 frame. It is a figure for demonstrating the production | generation process of the image data before 1 frame. It is a figure for demonstrating the production | generation process of the image data before 1 frame. 3 is a flowchart showing the operation of the image processing apparatus for driving a liquid crystal according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input terminal, 2 Receiving part, 3 Image data processing part, 4 Coding part, 5 Delay part, 6,7 Decoding part, 8 Change amount calculation part, 9 Code data determination part, 10 1 frame previous image data calculation part 11 Image data correction unit, 12 display unit, 11a lookup table, 11b correction unit.

Claims (15)

An image processing device for correcting and outputting image data representing a gradation value of each pixel of an image based on a change in gradation value in each pixel,
The image of the current frame is divided into a plurality of blocks, and includes a representative value indicating the size of pixel data in each block, and a quantized value obtained by quantizing the pixel data in each block based on the representative value. Encoding means for outputting first encoded image data corresponding to the image of the current frame;
Decoding means for outputting first decoded image data corresponding to the image of the current frame by decoding the first encoded image data;
Delay means for outputting second encoded image data corresponding to an image one frame before the current frame by delaying the first encoded image data for a period corresponding to one frame;
Decoding means for outputting second decoded image data corresponding to an image one frame before the current frame by decoding the second encoded image data;
With reference to the first encoded image data and the second encoded image data, the change amount of the representative value between the image of the current frame and the image of the previous frame, and the quantized value Code data determination means for obtaining a control signal representing a change in pixel data in each block of the current frame based on these change amounts;
One-frame-before-image calculation means for selecting one of the image data of the current frame and the second decoded image data for each pixel and generating one-frame-before-image data based on the control signal;
An image processing apparatus comprising: image data correction means for correcting a gradation value of an image of the current frame based on the image data of the previous frame and the image data of the current frame. The encoding means uses an average value of pixel data in each block and a dynamic range as the representative value,
The image processing apparatus according to claim 1, wherein the determination unit obtains a change amount of the average value and a change amount of the dynamic range as the change amount of the representative value. The code data determination means outputs a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 in a block in which the change in the representative value is smaller than a predetermined threshold as a still image, For a pixel whose quantization value change amount exceeds 1, a second control signal that is regarded as a moving image is output,
The one-frame-previous image calculation means selects the image data of the current frame for the pixel to which the first control signal is output, and the second decoded image for the pixel to which the second control signal is output. The image processing apparatus according to claim 1, wherein the image data is selected to generate the image data before one frame. The image processing apparatus according to claim 3, wherein the code data determination unit outputs a second control signal that regards all pixels in a block in which the change in the representative value is greater than a predetermined threshold as a moving image. . A change amount calculating means for calculating a change amount between the first decoded image data and the second decoded image data for each pixel;
The code data determination means outputs a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 in a block in which the change in the representative value is smaller than a predetermined threshold as a still image, For a pixel whose quantization value change amount exceeds 1, a second control signal that is regarded as a moving image is output,
The one-frame-previous image calculation means includes a pixel whose change amount between the first decoded image data and the second decoded image data is smaller than a predetermined threshold, and a pixel to which the first control signal is output Is selected, the change amount between the first decoded image data and the second decoded image data exceeds a predetermined threshold value, and the second control signal is output. 3. The image processing apparatus according to claim 1, wherein the second decoded image data is selected for the pixel to generate the one-frame previous image data. 4. The image processing apparatus according to claim 5, wherein the code data determination unit outputs a second control signal that regards all pixels in a block in which the change in the representative value is greater than a predetermined threshold as a moving image. . A change amount calculating means for calculating a change amount between the first decoded image data and the second decoded image data for each pixel;
The code data determination means outputs a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 in a block in which the change in the representative value is smaller than a predetermined threshold as a still image, For a pixel whose quantization value change amount exceeds 1, a second control signal that is regarded as a moving image is output,
The one-frame-previous image calculation means outputs a pixel whose change amount between the first decoded image data and the second decoded image data is smaller than a first threshold, and the first control signal. For the pixel, the image data of the current frame is selected, the amount of change between the first decoded image data and the second decoded image data exceeds the second threshold value, and the second control signal is output. The second decoded image data is selected for the processed pixels, and the amount of change between the first decoded image data and the second decoded image data is the first threshold value and the second threshold value. For the pixel from which the second control signal is output, the weighted average value of the image data of the current frame and the second decoded image data is selected for the one frame. To generate the previous image data The image processing apparatus according to claim 1 or 2, symptoms. An image display device comprising the image processing device according to claim 1. An image processing method for correcting and outputting image data representing a gradation value of each pixel of an image based on a change in gradation value in each pixel,
The image of the current frame is divided into a plurality of blocks, and includes a representative value indicating the size of pixel data in each block, and a quantized value obtained by quantizing the pixel data in each block based on the representative value. Outputting the first encoded image data corresponding to the current frame image;
Outputting the first decoded image data corresponding to the image of the current frame by decoding the first encoded image data;
Outputting the second encoded image data corresponding to the image one frame before the current frame by delaying the first encoded image data for a period corresponding to one frame;
Outputting the second decoded image data corresponding to the image one frame before the current frame by decoding the second encoded image data;
With reference to the first encoded image data and the second encoded image data, the change amount of the representative value between the image of the current frame and the image of the previous frame, and the quantized value Generating a control signal representing a change in pixel data in each block of the current frame based on the amount of change,
Selecting one of the current frame image data and the second decoded image data for each pixel based on the control signal to generate one frame previous image data;
And a step of correcting a gradation value of an image of the current frame based on the image data of the previous frame and the image data of the current frame. Using the average value of pixel data in each block and the dynamic range as the representative value,
The image processing method according to claim 9, wherein the change amount of the average value and the change amount of the dynamic range are obtained as the change amount of the representative value. In a block in which the change in the representative value is smaller than a predetermined threshold, a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 is regarded as a still image is output, and the change amount of the quantization value If the pixel exceeds 1, output a second control signal that considers it as a movie,
For the pixel to which the first control signal is output, the image data of the current frame is selected, and for the pixel to which the second control signal is output, the second decoded image data is selected and one frame before The image processing method according to claim 9 or 10, wherein image data is generated. 11. The image processing method according to claim 10, wherein a second control signal that is regarded as a moving image is output for all pixels in a block in which the change in the representative value is greater than a predetermined threshold. A step of calculating, for each pixel, a change amount between the first decoded image data and the second decoded image data;
In a block in which the change in the representative value is smaller than a predetermined threshold, a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 is regarded as a still image is output, and the change amount of the quantization value If the pixel exceeds 1, output a second control signal that considers it as a movie,
The image data of the current frame is selected for a pixel whose change amount between the first decoded image data and the second decoded image data is smaller than a predetermined threshold and a pixel to which the first control signal is output. For a pixel in which the amount of change between the first decoded image data and the second decoded image data exceeds a predetermined threshold and the second control signal is output, the second decoded image is used. The image processing method according to claim 9 or 10, wherein data is selected to generate the image data before one frame. The image processing method according to claim 13, wherein a second control signal that is regarded as a moving image is output for all pixels in a block in which the change in the representative value is greater than a predetermined threshold. A step of calculating, for each pixel, a change amount between the first decoded image data and the second decoded image data;
In a block in which the change in the representative value is smaller than a predetermined threshold, a first control signal that regards a pixel in which the change amount of the quantization value is 0 or 1 is regarded as a still image is output, and the change amount of the quantization value If the pixel exceeds 1, output a second control signal that considers it as a movie,
For the pixel whose change amount between the first decoded image data and the second decoded image data is smaller than the first threshold, and the pixel from which the first control signal is output, the image data of the current frame is used. The second decoding is performed for a pixel that has been selected and whose change amount between the first decoded image data and the second decoded image data exceeds the second threshold value and the second control signal is output. And the amount of change between the first decoded image data and the second decoded image data is a value between the first threshold value and the second threshold value, and For the pixel to which the second control signal is output, the one frame previous image data is generated by selecting a weighted average value of the image data of the current frame and the second decoded image data. Claims 9 or 10 Image processing method.

Images