JP2007139936A - Image processor, image display device and image processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor and an image processing method capable of appropriately correcting an input image data based on a variation of a grayscale value between frames of input image data, and a temperature of a display panel or its neighborhood or its surroundings, and to provide an image display device. <P>SOLUTION: The image processor comprises: a previous frame image data output section 14 for outputting an image data D<SB>p0</SB>of a previous frame; a control signal generation section 11 for generating a control signal T<SB>p1</SB>based on a comparison result of a temperature data corresponding to a temperature detection signal of the display panel, with a reference temperature data; and an image data correction section 10 in which correction data are selected from a lookup table (LUT) according to temporal change of the grayscale value in each pixel, and based on the selected correction data and the control signal T<SB>p1</SB>, the grayscale value of the current image data D<SB>i1</SB>is corrected and thereby, an image data D<SB>j1</SB>after correction is generated. A bit number of the correction data held by the LUT is larger than that of the image data D<SB>j1</SB>after correction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and an image processing method for correcting input image data based on a change amount of a gradation value between frames of the input image data and a temperature of the display panel or its vicinity or surroundings, and The present invention relates to an image display device including an image processing device.

  In general, a liquid crystal panel is not suitable for displaying a moving image that changes quickly because a certain amount of time is required until a predetermined transmittance corresponding to the gradation value of image data is reached after a driving voltage is applied. For this reason, a driving method is proposed in which an overvoltage is applied to the liquid crystal so that the liquid crystal reaches a predetermined transmittance corresponding to the gradation value of the image data within one frame when the gradation value changes between frames. (For example, refer to 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 amount of change of the gradation value is set to the current frame. Is added to the image data. By such a driving method, when the gradation value increases from the previous frame, a higher driving voltage is applied to the liquid crystal panel, and when the gradation value decreases from the previous frame, the liquid crystal panel A driving voltage lower than usual is applied at.

  However, when the driving voltage of the liquid crystal panel is increased or decreased using the correction amount based only on the temporal change of the gradation value, the driving voltage can be appropriately increased or decreased when the liquid crystal panel temperature changes. It may not be possible. For this reason, when the liquid crystal panel temperature is high, a driving voltage higher than an appropriate voltage is applied to the liquid crystal panel, and when the liquid crystal panel temperature is low, a driving voltage lower than an appropriate voltage is applied to the liquid crystal panel, Degradation of image quality occurs. In order to solve such problems, the optimum correction data at one reference temperature is prepared in advance, the correction amount is obtained by subtracting the current frame data from the correction data, and the calculation according to the temperature near the liquid crystal panel A drive method for controlling (increase or decrease) the correction amount by adding the corrected amount to the current frame data to obtain corrected image data, and applying a voltage based on the corrected image data to the liquid crystal Has been proposed (see, for example, Patent Document 2).

Japanese Patent No. 2616652 Japanese Patent No. 3673257

  However, the correction amount is obtained by subtracting the current frame data from the correction data prepared in advance, and the correction amount is controlled (increased or decreased) by calculation according to the temperature in the vicinity of the liquid crystal panel. In the driving method described in Patent Document 2 in which corrected image data is obtained by adding to current frame data, the correction data corresponds to the temperature when the correction data is the maximum gradation or the minimum gradation displayed on the liquid crystal panel. If the correction amount is decreased (for example, in the case of a broken line 13b in FIG. 13 described later), the correction amount becomes insufficient, and an appropriate driving voltage corresponding to the temperature in the vicinity of the liquid crystal panel cannot be applied to the liquid crystal (for example, In the case of a broken line 15b in FIG.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and its purpose is to change the gradation value between frames of input image data, and the display panel or its vicinity or surroundings. An object is to provide an image processing device, an image processing method, and an image display device capable of appropriately correcting input image data based on temperature.

  An image processing apparatus according to the present invention is an image processing apparatus that receives image data representing a gradation value of each pixel of a display panel, corrects the image data, and outputs corrected image data. One frame previous image data output unit for sequentially outputting image data, outputting one frame previous image data corresponding to one frame previous image data of the current frame, and holding at least one reference temperature data, the display panel Alternatively, a control signal generation unit that receives a temperature detection signal in the vicinity or surrounding thereof and generates a control signal based on a comparison result between the temperature data corresponding to the temperature detection signal and the reference temperature data, and the gradation in each pixel A data table corresponding to the temporal change of the value, and the correction data is extracted from the data table according to the temporal change of the gradation value in each pixel. And an image data correction unit that generates the corrected image data by correcting the gradation value of the image data of the current frame based on the selected correction data and the control signal. The number of bits of the correction data held in the data table of the image data correction unit is larger than the number of bits of the corrected image data.

  The image display device according to the present invention includes an image processing unit that outputs image data, and a display unit that displays an image based on the image data output from the image processing unit, and the image processing unit includes: The image processing apparatus.

  An image processing method according to the present invention is an image processing method for inputting image data representing a gradation value of each pixel of a display panel, correcting the image data, and outputting corrected image data. The image data of the frame is sequentially input, the image data of the previous frame corresponding to the image data of the previous frame of the current frame is output, the at least one reference temperature data is held, and the display panel or its vicinity or surrounding A data table that receives a temperature detection signal, generates a control signal based on a comparison result between the temperature data corresponding to the temperature detection signal and the reference temperature data, and corresponds to a temporal change in the gradation value in each pixel The correction data is selected according to the temporal change of the gradation value in each pixel, and based on the selected correction data and the control signal, the correction data is selected. The corrected image data is generated by correcting the gradation value of the image data of the current frame, and the number of bits of the correction data held in the data table is larger than the number of bits of the corrected image data. It is said.

  According to the image processing device, the image display device, and the image processing method of the present invention, since the correction data having a larger number of bits than the corrected image data is included, the ideal correction data is larger than the maximum gradation of the corrected image data. Even if it is larger or smaller than the minimum gradation, it is possible to obtain the effect that the image data can be corrected accurately and the appropriately corrected drive voltage can be applied to the display panel.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of an image display device including an image processing device 3 according to Embodiment 1 of the present invention. As shown in FIG. 1, the image display apparatus has a reception unit 2, an image processing device 3, a control signal generation unit 11, a display unit 12, and a temperature detection unit 13 as main components. In addition, the configuration indicated as “... Part” in the present application is realized by hardware including an electric circuit, etc., realized by software, or realized by a combination of software and hardware. Either may be sufficient. The image processing apparatus 3 is an apparatus that can implement the image processing apparatus of the present invention. The image display device shown in FIG. 1 is, for example, a liquid crystal television.

The receiving unit 2 is composed of a TV tuner or the like, and performs an image (current image) for one frame by performing processing such as channel selection and demodulation on the video signal input via the input terminal 1. Current image data D _i1 to be represented is generated and sequentially output to the image processing device 3.

The image processing device 3 includes an encoding unit 4, a delay unit 5, a first decoding unit 6, a second decoding unit 7, a change amount calculation unit 8, and a one-frame previous image calculation unit 9. And an image data correction unit 10. The image processing apparatus 3 generates tertiary corrected image data D _j1 corresponding to the current image data D _i1 . The first corrected image data (D _k1 in FIG. 3) and the second corrected image data (D _n1 in FIG. 3) will be described later.

Control signal generating unit 11 holds the reference temperature data indicative of at least one reference temperature T _0. The control signal generation unit 11 measures the display panel of the display unit 12 or its vicinity or ambient temperature measured by the temperature detection unit 13 (hereinafter, the display panel temperature or its vicinity or ambient temperature is also referred to as “measurement temperature”). T ₁ is compared with reference temperature T _0, and a control signal T _p1 based on the comparison result is output to image data correction unit 10. Note that the temperature of the display panel or its vicinity or ambient is not limited to the temperature of the display panel itself, but includes a temperature corresponding to the temperature of the display panel.

  The display panel of the display unit 12 is, for example, a liquid crystal panel, and by changing the light transmittance of each pixel of the liquid crystal by applying a voltage corresponding to the image data representing the luminance or density of the image to the liquid crystal, Display an image.

Next, the operation of the image processing apparatus 3 will be described. The encoding unit 4 compresses the data amount by encoding the current image data D _i1 to generate encoded image data D _a1 . As an encoding method by the encoding unit 4, for example, block encoding (BTC) such as FBTC (Fixed Block Truncation Coding) or GBTC (Generalized Block Truncation Coding) can be used. Further, as an encoding method in the encoding unit 4, two-dimensional discrete cosine transform encoding represented by JPEG, predictive encoding represented by JPEG-LS, and an encoding method using wavelet transform represented by JPEG2000 are used. Can be adopted. Further, any encoding scheme can be adopted as long as it is a still image encoding scheme. Note that the still image encoding method employed may be lossy encoding in which the image data before encoding and the image data after decoding do not completely match.

The delay unit 5 outputs the encoded image data D _a0 one frame before by delaying the encoded image data D _a1 generated by the encoding unit 4 for a period corresponding to one frame. As the encoding rate (data compression rate) of the image data D _{i1 in} the encoding unit 4 is increased, the storage capacity of the memory (not shown) of the delay unit 5 required for delaying the encoded image data D _a1 is increased. Can be small.

The first decoding unit 6 decodes the encoded image data D _a1 generated by the encoding unit 4 to thereby generate a first decoded image corresponding to the current image represented by the current image data D _i1. Data _Db1 is generated. In parallel with this processing, the second decoding unit 7 decodes the encoded image data D _a0 delayed by the delay unit 5, so that the second decoding unit 7 corresponds to the image one frame before the current image. Decoded image data _Db0 is generated.

Based on the first decoded image data D _b1 corresponding to the current image and the second decoded image data D _b0 corresponding to the image one frame before, the change amount calculation unit 8 generates the second decoded image data. by subtracting the first decoded image data D _b1 from the D _b0, it calculates the amount of change D _v1 of the gradation values of each pixel to the current image from the previous frame image. The change amount D _v1 and the current image data D _i1 are input to the previous frame image calculation unit 9.

The one-frame-before image calculation unit 9 adds the change amount D _v1 of the gradation value output from the change amount calculation unit 8 to the current image data D _i1 so as to correspond to the image data one frame before. Image data _Dp0 is generated. The one-frame previous image data D _p0 is input to the image data correction unit 10.

Based on the result of comparing the current image data D _i1 and the previous frame image data D _p0 and the control signal T _p1 , the image data correction unit 10 performs a one-frame period of the liquid crystal at or near the liquid crystal panel or the ambient temperature T ₁ . the current image data D _i1 to be a predetermined transmittance specified by correcting the current image data D _i1 within, and outputs the third order corrected image data D _j1.

2A to 2C are diagrams showing response characteristics when a driving voltage based on the third-corrected image data D _j1 is applied to the liquid crystal. 2A shows the time change of the gradation value (luminance value) of the current image data D _i1 , and FIG. 2B shows the time change of the gradation value (luminance value) of the third-order corrected image data D _j1. Indicates. In FIG. 2C, the solid line indicates the time change of the display luminance of the liquid crystal panel (that is, the response characteristic of the liquid crystal panel) obtained by applying the driving voltage based on the third corrected image data D _j1 , and the broken line Indicates the response characteristics of the liquid crystal panel when the drive voltage (V _H or V _L shown in FIG. 2B) is continuously applied based on the third corrected image data D _j1 . As shown in FIG. 2B, when the gradation value increases or decreases, the third corrected image data D _{j1 is} obtained by adding or subtracting the correction amount V ₁ or V ₂ to the current image data D _i1. Is generated. By applying a driving voltage based on the third-corrected image data D _j1 to the liquid crystal, as shown by a solid line in FIG. 2 (c), the gradation value of the current image data D _i1 is displayed on the liquid crystal within approximately one frame period. It is possible to reach a predetermined transmittance corresponding to.

FIG. 3 is a block diagram showing a configuration of the image data correction unit 10 shown in FIG. As illustrated in FIG. 3, the image data correction unit 10 includes a lookup table (LUT) 101, a subtraction unit 102, a correction amount control unit 103, an addition unit 104, and a restriction unit 105. . The LUT 101 includes a liquid crystal panel 1 or a liquid crystal panel having a predetermined transmittance specified by the current image data D _i1 within one frame period when the temperature T ₁ near or around the liquid crystal panel is equal to the reference temperature data T _0. Next corrected image data _Dk1 is set in advance.

FIG. 4 is a diagram schematically showing the configuration of the LUT 101 shown in FIG. The LUT 101 receives the current image data D _i1 and the previous frame image data D _p0 as read addresses. If the current image data _{D i1} and the previous frame image data _{D p0} is the image data of 8 bits each, 256 × 256 pieces of data in LUT101 is stored as the primary corrected image data _{D k1.} The LUT 101 reads out the image data dt (D _i1 , D _p0 ) corresponding to the values of the current image data D _i1 and the image data D _p0 of the previous frame, and performs primary correction image data D _k1 (= dt (D _i1 , _Dp0 )).

As shown in FIG. 3, the subtraction unit 102 generates a correction amount D ₁₁ by subtracting the current image data D _i1 from the primary corrected image data D _k1 from the LUT 101.

Correction amount control unit 103, the correction amount D _l1 control the correction amount is controlled based on the control signal T _p1 and (increase or decrease, or remain in its maintenance), dried ( "after the temperature control correction amount on the basis of a control signal T _{p1 Is} also generated.) D _m1 is generated. Here, when the control signal T _p1 is a signal indicating that the temperature T _{1 at} or near the display panel or in the vicinity thereof is higher than the reference temperature T ₀ , the absolute value | D of the post-temperature control correction amount D _{m1 m1} | is the absolute value of the correction amount _{D l1 | D l1 |} controls so than smaller. Further, the control signal _{T p1} is, when the temperature _{T 1} of the display panel or the vicinity or around the reference temperature _T lower than _0, the absolute value of the temperature control after the correction amount _{D m1 | D m1 |} correction amount _{D l1} To be larger than the absolute value | D _I1 |. As a correction method at that time, for example, the following formula D _m1 = α × D ₁₁
As described above, the correction amount D _m1 after temperature control is calculated by multiplying the correction amount D ₁₁ by a temperature correction coefficient α having a value corresponding to the control signal T _p1 .

The adder 104 adds the post-temperature control correction amount D _m1 obtained by the correction amount control unit 103 to the current image data D _i1 to generate secondary corrected image data D _n1 .

The restricting unit 105 generates the image data after the third correction D _j1 by restricting the image data after the second correction D _n1 to a range of values that the display unit 12 can receive. Here, the range of values that can be received by the display unit 12 is determined by the number of bits of input data to the display unit 12. For example, when the number of bits of input data to the display unit 12 is 8 bits, the range of values that can be received by the display unit 12 is 0 to 255. In this case, when the image data D _n1 after the secondary correction is smaller than 0, the image data D _j1 after the tertiary correction is set to 0 (ie, D _j1 = 0), and the image data D _n1 after the secondary correction is larger than 255. In this case, the third-corrected image data D _{j1 is set} to 255 (that is, D _j1 = 255). If the second-corrected image data D _n1 is in the range of 0 to 255, the third-corrected image data D _{j1 Is} made the same as the image data D _n1 after the secondary correction (that is, D _j1 = D _n1 ) to obtain the image data D _j1 after the tertiary correction.

Next, a description will be given first order corrected image data _{D k1} set in the LUT 101. Assuming that the number of bits of the input image data is 8 bits (0 to 255), when the current image data D _i1 has 127 gradations, a voltage V ₅₀ is applied to the liquid crystal so that the transmittance is 50%. . Similarly, when the current image data D _i1 has 191 gradations, a voltage V ₇₅ that sets the transmittance to 75% is applied to the liquid crystal. FIG. 5 is a graph showing response characteristics when a voltage V ₅₀ and a voltage V ₇₅ are respectively applied to a liquid crystal having a transmittance of 0% in a graph of response time (s) and transmittance (%). As shown in FIG. 5, it may take a response time longer than one frame period for the liquid crystal to reach the predetermined transmittance specified by the applied voltage. Therefore, when the gradation value of the current image changes, the response speed of the liquid crystal can be improved by applying a voltage such that the transmittance when one frame period elapses becomes a desired transmittance.

In the example shown in FIG. 5, when the voltage V ₇₅ is applied to the liquid crystal, the transmittance of the liquid crystal when one frame period elapses is 50%. Thus, target transmissivity can be a liquid crystal with desired transmittance in one frame period by the case of 50%, an applied voltage of the liquid crystal and V _75. That is, when the current image data D _i1 changes from 0 to 127, the current image data D _{i1 is set} to 191 (that is, D _i1 = 191), and is output to the display unit 11 to obtain a desired value within one frame period. A voltage that gives a transmittance is applied to the liquid crystal.

FIG. 6 is a diagram illustrating an example of the response speed of the liquid crystal. In FIG. 6, the x-axis indicates the value of the current image data D _i1 (the tone value in the image of the current frame), and the y-axis indicates the value of the image data D _p0 one frame before (the tone value in the image one frame before). The z axis indicates the response time (ms) required for the liquid crystal to reach the transmittance corresponding to the gradation value of the current image data D _i1 from the transmittance corresponding to the gradation value of the image data D _p0 one frame before. Yes. Here, when the gradation value of the current image data is 8 bits, there are 256 × 256 combinations of gradation values in the current frame image and the image one frame before the current frame, so the response speed is also 256 ×. There are 256 ways. In FIG. 6, the response speed corresponding to the combination of gradation values is simplified and shown in 8 × 8 ways.

FIG. 7 is a diagram illustrating a correction amount of the current image data D _i1 that sets the liquid crystal to a transmittance corresponding to the value of the current image data D _i1 when one frame period elapses. In FIG. 7, the x-axis indicates the value of the current image data D _i1 (the tone value in the image of the current frame), and the y-axis indicates the value of the image data D _p0 one frame before (the tone value in the image one frame before). The z axis indicates the correction amount of the current image data D _i1 . When the gradation value of the current frame image is 8 bits, there are 256 × 256 correction amounts corresponding to combinations of gradation values in the current frame image and the image one frame before the current frame. In FIG. 7, the correction amount corresponding to the combination of gradation values is simplified and shown in 8 × 8 ways.

As shown in FIG. 6, the response speed of the liquid crystal is different for each gradation value in the current frame image and the image one frame before the current frame. Therefore, the correction amount cannot be obtained by a simple calculation formula. Therefore, in the LUT 101, as shown in FIG. 8, the current image data D _i1 includes 256 × corresponding to the gradation values of the current frame image data D _i1 and the previous frame image data D _p0 shown in FIG. The first corrected image data _Dk1 obtained by adding 256 correction amounts is stored. Liquid crystal response characteristics of liquid crystal materials, since changes depending on the electrode shape, by using a LUT101 having a primary corrected image data D _k1 corresponding to such various use conditions, depending on the characteristics of the liquid crystal panel The response speed can be controlled.

Further, the correction amount shown in FIG. 7 is set so that the correction amount for the combination of gradation values having a slow response speed of the liquid crystal is large. For example, when the response speed when changing from intermediate luminance (gray) to high luminance (white) is slow, it corresponds to image data D _i0 one frame before representing intermediate luminance and current image data D _i1 representing high luminance. The response speed can be effectively improved by setting the value of the number of gradations to be large in the positive direction or the negative direction.

Hereinafter, the third corrected image generated when the LUT 101 is configured by the first corrected image data D _k1 having a larger number of bits than the third corrected image data D _j1 (that is, in the case of the present invention). the data D _j1, if constituted by tertiary corrected image data D _{j1 'after} the same number of bits of the primary corrected image data D _k1' (i.e., the case of Comparative example) tertiary corrected image to be generated This will be described in comparison with the data D _j1 ′.

FIG. 9 shows the case where the current image data D _i1 ′ and the first corrected image data when the first corrected image data D _k1 ′ and the third corrected image data D _j1 ′ have the same number of bits (that is, in the comparative example). It is a graph which shows the relationship of image data _Dk1 '. In FIG. 9, the solid line 9a shows an example of the first corrected image data D _k1 ′ when the value of the image data D _p0 ′ before one frame is the gradation L ₀ . In FIG. 9, a broken line 9b shows a case where the primary corrected image data D _k1 ′ is equal to the current image data D _i1 ′. As shown in FIG. 9, when D _i1 ′> L _0, that is, D _i1 ′> D _p0 ′, the post-primary correction image data D _k1 ′ is larger than the current image data D _i1 ′. On the other hand, when D _i1 ′ <L _0, that is, D _i1 ′ <D _p0 ′, the first corrected image data D _k1 ′ is smaller than the current image data D _i1 ′. Here, for simplicity, 1 _', the current image data D _i1' primary corrected image data D _k1 shows the graph when the changes linearly in accordance with the magnitude of the current image data D _{i1 '} The case of 8 bits (0 to 255) is shown.

As shown in FIG. 9, in the comparative example in which the first corrected image data D _k1 ′ and the third corrected image data D _j1 ′ have the same number of bits, the first corrected image data D _k1 ′ is _'because not be smaller than the minimum value of the current image data D _i1' current image data D _i1 when the following gradation value L _1, the all primary corrected image data D _{k1 'is} 0. Further, in the comparative example, after the first corrected image data D _{k1 'is} the current image data D _i1' because not be greater than the maximum value of the current picture data D _{i1 'is} not less than the gradation value L ₂ Is all the post-primary corrected image data D _k1 ′ is 255. Here, L ₁ is the maximum value of the current image data D _i1 ′ at which the image data D _k1 ′ after the primary correction is 0, and L ₂ is the current value at which the image data D _k1 ′ after the primary correction is 255. This is the minimum value of the image data D _i1 ′.

FIG. 10 shows the current image data D _i1 and the post-primary correction in the case where the number of bits of the first corrected image data D _k1 is larger than the number of bits of the third corrected image data D _j1 (that is, in the present invention). It is a graph which shows the relationship of image data _Dk1 . 10, a solid line 10a indicates the value of the previous frame image data _{D p0} is when the gradation value _{L 0,} an example of a first order corrected image data _{D k1.} 10, the broken line 10b is the primary corrected image data _{D k1} indicates the equal to the current image data _{D i1.} In this case, since the image data D _k1 after the primary correction can take a value larger than the maximum value or smaller than the minimum value of the image data D _j1 after the tertiary correction, the current image data D _i1 is the gradation value L _1. primary corrected image data D _k1 in the following cases and 0 following values, the current image data D _i1 gradation value L ₂ or more when the primary corrected image data D _k1 becomes 255 or more.

11, in the case where a relationship such as the current image data D _{i1 'and} the primary corrected image data D _k1' is shown in FIG. 9 (i.e., in the case of the comparative example), the correction and the current image data D _{i1 '} It is a graph which shows the relationship of quantity _Dl1 '. Current image data _{D i1} 'in is larger than the gradation value _{L 1} smaller than the gradation value _{L 0} is the current image data _{D i1'} correction amount _{D l1} becomes smaller 'is smaller, the current image data _{D i1} 'when the following gradation value L ₁ is the current image data D _i1' correction amount D _{l1 'becomes} large, the current image data D _i1' becomes smaller primary corrected image data in the case of 0 D _k1 ′ becomes zero. When the current image data D _i1 ′ is larger than the gradation value L _{0 and} smaller than the gradation value L _{2, the} correction amount D ₁₁ ′ increases as the current image data D _i1 ′ increases, but the current image data D _i1 'when the above gradation value _{L 2} is the current image data _{D i1'} correction amount _{D l1} accordance larger 'decreases, the current image data _{D i1'} 1 primary corrected in the case of 255 The image data D _k1 ′ is zero. This is because even when data of 0 or less or 255 or more should be set in the post-primary-corrected image data D _k1 ′ in order to give an ideal acceleration voltage to the liquid crystal panel, the primary correction is performed. since the number of bits is equal to the rear image data D _{k1 'number} of bits and the third-order corrected image data D _j1', because the only value in the range of 0 to 255 in the primary corrected image data D _{k1 'can} not be set.

FIG. 12 shows the current image data D _i1 and the correction amount D ₁₁ when the current image data D _i1 and the first corrected image data D _k1 have the relationship as shown in FIG. 10 (that is, in the case of the present invention). It is a graph which shows the relationship. In this case, when the current image data _{D i1} is smaller larger than the gradation value _{L 1} than the gradation value _{L 0} is the correction amount _{D l1} accordance current image data _{D i1} is smaller decreases, the current image data _{D i1} Even in the case of the gradation value L ₁ or less, the correction amount D ₁₁ becomes smaller as the current image data D _i1 becomes smaller. Also, when the current image data _{D i1} is large gradation value _{L 2} smaller than the gradation value _{L 0} is the correction amount _{D l1} accordance current image data _{D i1} increases increases, the current image data _{D i1} is floors in each case adjustment value _{L 2} or more, the correction amount _{D l1} accordance current image data _{D i1} increases increases.

FIG. 13 shows how the correction amount control unit 103 increases or decreases the correction amount D _l1 ′ according to the control signal T _p1 , and the first corrected image data D _k1 ′ and the third corrected image data. The graph shows an example of current image data D _i1 ′ and post-temperature control correction amount D _m1 ′ when the number of bits of D _j1 ′ is the same (that is, in the case of the comparative example). A solid line 13a in FIG. 13 is a post-temperature control correction amount D _m1 ′ when the control signal T _p1 indicates that the reference temperature T ₀ and the neighboring temperature T ₁ are equal. In this case, the post-temperature control correction is performed. The amount D _m1 ′ is equal to the first corrected image data D _k1 ′. A broken line 13b in FIG. 13 represents the post-temperature control correction amount D _m1 ′ when the control signal T _p1 indicates that the temperature T _{1 in the} vicinity is higher than the reference temperature T ₀ . A broken line 13c in FIG. 13 indicates the post-temperature control correction amount D _m1 ′ when the control signal T _p1 indicates that the temperature T _{1 in the} vicinity is lower than the reference temperature T ₀ . In FIG.
D _m1 ′ = α ′ × D _l1 ′
As shown in the graph, the correction amount D _m1 ′ after temperature control is obtained by multiplying the correction amount D ₁₁ by a certain coefficient α ′. The solid line 13a in FIG. 13 is for α ′ = 1, the dotted line 13b in FIG. 13 is for α ′ <1, and the dashed line 13c in FIG. 13 is for α ′> 1.

FIG. 14 is a graph showing secondary corrected image data D _n1 ′ generated by adding the post-temperature control correction amount D _m1 ′ to the current image data D _i1 ′ in the comparative example shown in FIG. 13. It is. In FIG. 14, the solid line 14 a is the secondary corrected image data D _n1 ′ in the case of the solid line 13 a in FIG. 13, and the broken line 14 b is the secondary corrected image data D _n1 ′ in the case of the broken line 13 b in FIG. 13. Yes, the broken line 14c is the secondary corrected image data D _n1 ′ in the case of the broken line 13c in FIG.

In FIG. 15, in the comparative example shown in FIGS. 13 and 14, the post-secondary corrected image data D _n1 ′ (14 a, 14 b, and 14 c in FIG. 14) is input to the display unit 12 by the restriction unit 105. 3 is a graph showing third-order corrected image data D _j1 ′ generated by limiting to a range of data. In FIG. 15, a solid line 15a is the third-corrected image data D _j1 ′ in the case of the solid line 14a in FIG. 14, and a broken line 15b is the third-corrected image data D _j1 ′ in the case of the broken line 14b in FIG. Yes, the broken line 15c is the secondary corrected image data D _j1 ′ in the case of the broken line 14c in FIG. When the tertiary corrected image data D _j1 ′ is 8 bits, D _n1 ′ <0 or D _n1 ′> 255 in the secondary corrected image data D _n1 ′ shown by the broken line 14c in FIG. By limiting the value of the secondary corrected image data in the range of D _n1 = 0 or D _n ′ = 255, it is possible to input to the display unit 12 as indicated by a broken line 15c in FIG. Image data D _j1 ′ after tertiary correction is obtained.

Here, paying attention to the broken line 15b in FIG. 15, when the current image data D _i1 ′ is smaller than the gradation value L ₁ and larger than the gradation value L ₂ , the third order with respect to the change of the current image data D _i1 ′. The amount of change in the corrected image data D _j1 ′ is small. In the example shown here, when the image data D _p0 ′ one frame before is constant, the response characteristic of the liquid crystal is linear with respect to the current image data D _i1 ′. Although the third-order corrected image data D _j1 ′ is ideally changed linearly, the current image data D _i1 ′ is smaller than the gradation value L ₁ and larger than the gradation value L _2. In this case, it can be seen that the third-corrected image data D _j1 ′ is insufficient.

FIG. 16 is a graph showing an example of the third corrected image data D _j1 ′ in the comparative example. A broken line 16a in FIG. 16 indicates the third-corrected image data D _j1 ′ when the correction for the current image data D _i1 ′ is insufficient as indicated by the broken line 15b in FIG. A solid line 16b in FIG. 16 indicates the third-corrected image data D _j1 ′ when the current image data D _i1 ′ is sufficiently corrected. The broken line 16a is deficient in the third-corrected image data D _j1 ′ in the region hatched with the diagonal line compared to the solid line 16b. In order to give an ideal acceleration voltage to the liquid crystal panel by setting the number of bits of the first corrected image data D _k1 ′ to the same number of bits as that of the third corrected image data D _j1 ′, This is because even if data of 0 or less or 255 or more should be set in the post-correction image data D _k1 ′, only a value in the range of 0 to 255 can be set.

Next, in the case where the number of bits of the first corrected image data D _k1 is larger than the number of bits of the third corrected image data D _j1 (that is, in the case of the present invention), The operation will be described. FIG. 17 shows how the correction amount control unit 103 increases or decreases the correction amount D ₁₁ according to the control signal T _p1 . The current image data D _i1 , the correction amount D _11, and the post-temperature control correction amount D are shown. An example of _m1 (shown in FIG. 3) is shown in a graph. A solid line 17a in FIG. 17 is the correction amount _D11 shown in FIG. Dashed line 17b in FIG. 17, the control signal _{T p1} is than the reference temperature _{T 0} is the temperature control after the correction amount _{D m1} when indicate that higher temperature _{T 1} of the vicinity of the broken line 17c in FIG. 17, An example of the post-temperature control correction amount D _m1 when the control signal T _p1 indicates that the temperature T _{1 in the} vicinity is lower than the reference temperature T ₀ is shown. here,
D _m1 = α × D ₁₁
As shown in the graph, the correction amount D _m1 after temperature control is obtained by multiplying the correction amount D ₁₁ by the coefficient α selected according to the temperature T ₁ . Note that α = 1 in the case of the solid line 17a in FIG. 17, α <1 in the case of the broken line 17b in FIG. 17, and α> 1 in the case of the broken line 17c in FIG.

FIG. 18 is a graph showing secondary post-correction image data D _n1 generated by adding the post-temperature control correction amount D _m1 to the current image data D _i1 in the case of the present invention shown in FIG. 18, the solid line 18a is the secondary corrected image data D _n1 in the case of the solid line 17a in FIG. 17, and the broken line 18b is the secondary corrected image data D _n1 in the case of the broken line 17b in FIG. A broken line 18c is image data D _n1 after the secondary correction in the case of the broken line 17c in FIG. As shown in FIG. 18, in the present invention, the number of bits of the first corrected image data D _n1 is larger than the number of bits of the third corrected image data D _j1 .

In FIG. 19, in the case of the present invention shown in FIGS. 17 and 18, the post-secondary corrected image data D _n1 (18 a, 18 b, 18 c in FIG. 18) is input to the display unit 12 by the limiting unit 105. It is a graph which shows the 3rd post-correction image data _Dj1 produced _| generated by restrict _| limiting to the range of data. In FIG. 19, a solid line 19a is the third-corrected image data D _j1 in the case of the solid line 18a in FIG. 18, and a broken line 19b is the third-corrected image data D _j1 in the case of the broken line 18b in FIG. A broken line 19c is image data D _j1 after the secondary correction in the case of the broken line 18c in FIG. When the tertiary corrected image data D _j1 is 8 bits, the secondary corrected image data D _n1 indicated by the broken line 18c in FIG. 18 has a range of D _n1 <0 or D _n1 > 255. By limiting the value of the image data after the secondary correction to D _n1 = 0 or D _n = 255, respectively, the image after the tertiary correction that can be input to the display unit 12 as indicated by a broken line 19c in FIG. Data D _j1 is obtained.

As shown by a broken line 19b in FIG. 19, even when the correction amount _D11 is decreased according to the measured temperature detection signal, the number of bits of the first corrected image data _Dk1 is the third corrected image data D. _{Since it} is larger than the number of bits of _j1 , it is possible to set a value smaller than 0 or a value larger than 255 as the value of the image data D _k1 after the primary correction, so that the correction amount D ₁₁ is set by the control signal T _p1 . Even in the case of a decrease (broken line 17b in FIG. 17, broken line 18b in FIG. 18, broken line 19b in FIG. 19), the third-corrected image data D _j1 is not insufficient. For this reason, according to the image processing device 3 of the first embodiment, the display unit 12 applies a voltage based on the third corrected image data D _j1 to the liquid crystal, so that the temperature of the liquid crystal panel or the vicinity or the surrounding temperature is applied. Accordingly, the liquid crystal can be driven appropriately.

As described above, the image processing apparatus 3 according to the first embodiment uses the number of bits of the first corrected image data D _k1 output from the LUT 101 as the third corrected image data D output from the limiting unit 105. by more than the number of bits _j1, since the primary corrected image data _{D k1} where the display unit 12 is out of the range of possible display brightness can be set to LUT 101, the correction in accordance with the control signal _{T p1} amount _{D l1} Even if is increased or decreased, the image data D _j1 after the third-order correction is not insufficient, and the liquid crystal can be appropriately driven according to the temperature of the liquid crystal panel, the vicinity thereof, or the surroundings.

Embodiment 2. FIG.
In the first embodiment, in the image data correction unit 10, the LUT 101 includes the liquid crystal panel in the current image data within one frame period when the temperature T ₁ near or around the liquid crystal panel is equal to the reference temperature data T _0. The primary corrected image data D _k1 is set so as to have a predetermined transmittance specified by D _i1, but in the second embodiment, the current image data from the primary corrected image data D _{k1 is} stored in the LUT. It is set a correction amount _{D l1} obtained by subtracting the D _i1.

FIG. 20 is a block diagram illustrating a configuration of the image data correction unit 10a of the image processing apparatus according to the second embodiment. In FIG. 20, the same or corresponding elements as those shown in FIG. The image processing apparatus according to the second embodiment corresponds to an image processing apparatus 3 shown in FIG. 1 in which the image data correction unit 10 is replaced with an image data correction unit 10a shown in FIG. The LUT 111 of the image data correction unit 10a shown in FIG. 20 receives the current image data D _i1 and the previous frame image data D _p0 and outputs a correction amount D ₁₁ . The output correction amount D ₁₁ is input to the correction amount control unit 103. In the image processing apparatus according to the second embodiment, as in the image processing apparatus according to the first embodiment, an appropriate post-temperature control correction amount D _m1 according to the temperature characteristics of the liquid crystal can be obtained.

  In the second embodiment, points other than those described above are the same as those in the first embodiment.

Embodiment 3 FIG.
In the first embodiment, as shown in FIG. 3, the correction amount control unit 103 multiplies the correction amount D ₁₁ by the coefficient α selected according to the temperature T ₁ of the liquid crystal panel or the vicinity thereof or the surroundings. Thus, a correction amount after correction based on the control signal T _p1 (also referred to as “correction amount after temperature control”) D _m1 is obtained. In the third embodiment, a plurality of coefficients α ₁ and α ₂ are used. Thus, a post-temperature control correction amount _Dm1 is obtained. In the third embodiment, the coefficient used for correcting the correction amount D ₁₁ based on the control signal T _p1 is selected in accordance _with the magnitude relationship between the current image data D _i1 and the previous frame image data D _p0. Yes. For example, when the current image data D _i1 is larger than the previous frame image data D _p0 (that is, D _i1 > D _p0 ), the correction amount D _m1 after temperature control is obtained by multiplying the correction amount D ₁₁ by the coefficient α _1. If the current image data D _i1 is smaller than the previous frame image data D _p0 (that is, D _i1 <D _p0 ), the temperature is controlled by multiplying the correction amount D ₁₁ by a coefficient α ₂ different from the coefficient α _1. A correction amount _Dm1 is obtained. Thus, by performing temperature control using a plurality of coefficients, it is possible to obtain an appropriate post-temperature control correction amount D _m1 according to the temperature characteristics of the liquid crystal.

  In the third embodiment, points other than those described above are the same as those in the first or second embodiment.

It is a block diagram which shows the structure of the image display apparatus provided with the image processing apparatus which concerns on Embodiment 1 thru | or 3 of this invention. (A)-(c) is a figure which shows the response characteristic of a liquid crystal, (a) shows the time change of the luminance value of present image data, (b) is the luminance value (liquid crystal) of the image data after 3rd correction | amendment. (C) shows a time change of the display luminance of the liquid crystal panel obtained by applying a voltage based on the third corrected image data of (b). 2 is a block diagram illustrating a configuration of an image data correction unit of the image processing apparatus according to Embodiment 1. FIG. FIG. 4 is a diagram schematically showing the configuration of the LUT shown in FIG. 3. It is a figure which shows an example of the time change of the transmittance | permeability of a liquid crystal. 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 with respect to the present image data. It is a figure which shows an example of the image data after primary correction | amendment stored in LUT which concerns on Embodiment 1 of this invention. It is a figure which shows the relationship between the present image data and the image data after primary correction | amendment in a comparative example. It is a figure which shows the relationship between the present image data and the image data after primary correction | amendment in Embodiment 1 of this invention. It is a figure which shows the relationship between the present image data and correction amount in a comparative example. It is a figure which shows the relationship between the present image data and correction amount in Embodiment 1 of this invention. It is a figure which shows the relationship between the present image data and the corrected amount after temperature correction in a comparative example. It is a figure which shows the relationship between the present image data and the image data after secondary correction | amendment in a comparative example. It is a figure which shows the relationship between the present image data and the image data after tertiary correction | amendment in a comparative example. In a comparative example, it is a figure which shows a mode that the image data after tertiary correction | amendment are insufficient. It is a figure which shows the relationship between the present image data and the corrected amount after temperature correction in Embodiment 1 of this invention. It is a figure which shows the relationship between the present image data and the image data after secondary correction | amendment in Embodiment 1 of this invention. It is a figure which shows the relationship between the present image data and the image data after tertiary correction | amendment in Embodiment 1 of this invention. It is a block diagram which shows the structure of the image data correction | amendment part of the image processing apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input terminal, 2 Receiving part, 3 Image processing part, 4 Coding part, 5 Delay part, 6 1st decoding part, 7 2nd decoding part, 8 Change amount calculation part, 9 1 frame previous image calculation Unit, 10, 10a image data correction unit, 11 control signal generation unit, 12 display unit, 13 temperature detection unit, 14 1 frame previous image data output unit, 101, 111 look-up table (LUT), 102 subtraction unit, 103 correction Amount control unit, 104 addition unit, 105 limiting unit, D _i1 current image data, D _k1 primary corrected image data, data obtained by adding primary correction image data to D ₁₁ current image data, D _m1 current image data Data obtained by correcting the data obtained by adding the first corrected image data based on the control signal T _p1 , D _n1 second corrected image data, D _j1 third corrected image data, D _v1 change amount calculation The amount of change in the gradation value output by the output unit, D _p0 one frame previous image data, T _p1 control signal.

Claims (17)

An image processing apparatus that receives image data representing a gradation value of each pixel of a display panel, corrects the image data, and outputs corrected image data.
1-frame-before-image data output unit for sequentially inputting image data of the current-frame, and outputting 1-frame-before-image data corresponding to the image-data 1-frame-before-the-current-frame;
Holds at least one reference temperature data, receives a temperature detection signal of the display panel or its vicinity or surroundings, and generates a control signal based on a comparison result between the temperature data corresponding to the temperature detection signal and the reference temperature data A control signal generator to
A data table corresponding to the temporal change of the gradation value in each pixel, and correction data is selected from the data table according to the temporal change of the gradation value in each pixel; An image data correction unit that generates the corrected image data by correcting the gradation value of the image data of the current frame based on the correction data and the control signal;
The number of bits of the correction data held in the data table of the image data correction unit is larger than the number of bits of the corrected image data.   2. The image according to claim 1, wherein the correction of the image data of the current frame by the image data correction unit includes a process of increasing or decreasing the value of the image data of the current frame based on the control signal. Processing equipment.   The correction of the image data of the current frame by the image data correction unit differs according to the magnitude relationship between the image data of the current frame and the image data of the previous frame. The image processing apparatus described. The display panel is a liquid crystal panel;
The correction data of the data table of the image data correction unit includes data indicating a voltage for setting the liquid crystal of the liquid crystal panel to a transmittance corresponding to the luminance value of the image data of the current frame within one frame period, and The image processing apparatus according to claim 1, comprising data larger than a maximum value of the corrected image data. The display panel is a liquid crystal panel;
The correction data of the data table of the image data correction unit includes data indicating a voltage for setting the liquid crystal of the liquid crystal panel to a transmittance corresponding to the luminance value of the image data of the current frame within one frame period, and The image processing apparatus according to claim 1, comprising data smaller than a minimum value of the corrected image data. The one frame previous image data output unit
An encoding unit that generates encoded image data corresponding to the image data of the current frame by encoding the image data of the current frame;
A first decoding unit that generates first decoded image data corresponding to the image data of the current frame by decoding the encoded image data;
A delay unit that delays the encoded image data for a period corresponding to one frame;
A second decoding unit that generates second decoded image data corresponding to image data one frame before the current frame by decoding the encoded image data delayed by the delay unit;
A change amount calculation unit that calculates a change amount between the first decoded image data and the second decoded image data for each pixel;
A one-frame-before image calculation unit that calculates the one-frame-before image data corresponding to the image data one frame before the current frame using the change amount and the image data of the current frame; The image processing apparatus according to claim 1. The correction data selected from the data table of the image data correction unit is data corresponding to two data of the current frame image data and the previous frame image data,
The image data correction unit
A subtraction unit that subtracts the image data of the current frame from the correction data output from the data table and outputs a correction amount;
A correction amount control unit that controls the correction amount output from the subtraction unit based on the control signal from the control signal generation unit;
An addition unit for adding the control amount after control output from the correction amount control unit to the image data of the current frame;
The image processing apparatus according to claim 1, further comprising: a restriction unit that restricts the number of gradations of the image data output from the addition unit. The correction data selected from the data table of the image data correction unit is data corresponding to two data of the current frame image data and the previous frame image data,
The image data correction unit
A correction amount control unit that controls a correction amount output from the data table based on the control signal from the control signal generation unit;
An addition unit for adding the control amount after control output from the correction amount control unit to the image data of the current frame;
The image processing apparatus according to claim 1, further comprising: a restriction unit that restricts the number of gradations of the image data output from the addition unit. An image processing unit for outputting image data;
A display unit for displaying an image based on the image data output from the image processing unit,
The image display device according to claim 1, wherein the image processing unit is the image processing device according to claim 1. An image processing method for inputting image data representing a gradation value of each pixel of a display panel, correcting the image data, and outputting corrected image data,
Image data of the current frame is sequentially input, and image data before one frame corresponding to image data of one frame before the current frame is output;
Holds at least one reference temperature data, receives a temperature detection signal of the display panel or its vicinity or surroundings, and generates a control signal based on a comparison result between the temperature data corresponding to the temperature detection signal and the reference temperature data And
From the data table corresponding to the temporal change in gradation value in each pixel, correction data is selected according to the temporal change in gradation value in each pixel, and the selected correction data and the control signal are selected. To generate the corrected image data by correcting the gradation value of the image data of the current frame,
The number of bits of the correction data held in the data table is larger than the number of bits of the corrected image data.   The image processing method according to claim 10, wherein the correction of the image data of the current frame includes a process of increasing or decreasing the value of the image data of the current frame based on the control signal.   12. The image processing method according to claim 10, wherein the correction of the image data of the current frame differs depending on a magnitude relationship between the image data of the current frame and the image data of the previous frame. The display panel is a liquid crystal panel;
The correction data of the data table includes data corresponding to a voltage that causes the liquid crystal of the liquid crystal panel to have a transmittance corresponding to the luminance value of the image data of the current frame within one frame period, and the corrected image data 13. The image processing method according to claim 10, comprising data larger than a maximum value of. The display panel is a liquid crystal panel;
The correction data of the data table includes data corresponding to a voltage that causes the liquid crystal of the liquid crystal panel to have a transmittance corresponding to the luminance value of the image data of the current frame within one frame period, and the corrected image data The image processing method according to claim 10, further comprising data smaller than a minimum value of. The process of outputting the previous frame image data includes:
Encode the current frame image data to generate encoded image data corresponding to the current frame image data,
Generating first decoded image data corresponding to the image data of the current frame by decoding the encoded image data;
The encoded image data is delayed for a period corresponding to one frame,
Decoding the delayed encoded image data to generate second decoded image data corresponding to image data one frame before the current frame;
A change amount between the first decoded image data and the second decoded image data is calculated for each pixel;
15. The processing according to claim 10, further comprising: calculating the previous frame image data corresponding to the previous frame image data using the amount of change and the current frame image data. An image processing method according to any one of the above. The correction data selected from the data table is data corresponding to two data of image data of the current frame and image data of the previous frame,
The process of outputting the image data one frame before corresponding to the image data one frame before the current frame,
Subtracting the current frame image data from the correction data output from the data table to output a correction amount,
Controlling the correction amount obtained by the subtraction based on the control signal;
Add the correction amount obtained by the subtraction to the image data of the current frame,
The image processing method according to claim 10, wherein the number of gradations of the image data obtained by the addition is limited. The correction data selected from the data table is data corresponding to two data of image data of the current frame and image data of the previous frame,
The process of outputting the image data one frame before corresponding to the image data one frame before the current frame,
Control the correction amount output from the data table based on the control signal,
Add the corrected amount after the control to the image data of the current frame,
The image processing method according to claim 10, wherein the number of gradations of the image data obtained by the addition is limited.

Images