JP6472995B2 - Image output system - Google Patents

Description

  The present invention relates to an image output system, and more particularly to an image output system that performs overdrive processing.

  In today's information processing devices, image output devices such as computer displays, television displays, and mobile displays are indispensable. As a display unit of the image output device, for example, there are a liquid crystal panel, an organic electroluminescence panel, and the like. The image output apparatus typically displays a desired image by applying a voltage to the image display element of the display unit based on image data to be displayed and driving the image display element. A decrease in the response speed of the image display causes flickering of the image and an afterimage, and thus the response speed of the image display is an important factor for such an image output apparatus.

  As a technique for improving the response speed of such an image output apparatus, a technique called overdrive processing for driving an image display element with a voltage having a higher amplitude than usual is known. In such overdrive processing, in order to determine the voltage to be applied to the image display element, the difference between the image data of one frame (time unit for displaying an image) before and the image data of the current frame is generally used. Specifically, in the overdrive process, the image data of the previous frame is stored in the frame memory, the image data of the previous frame is compared with the image data of the current frame, and the LUT (Look Up) is compared according to the comparison result. A correction amount is determined from (Table), and the voltage applied to the image display element is determined by correcting the image data of the current frame based on the determined correction amount.

  In order to reduce the amount of data stored in the frame memory in the overdrive process, the image data is encoded (compressed). In general, encoding is performed by thinning out color components of image data in the spatial direction or thinning out information on color components of image data by the lower bits. In such a technique, an image output device encodes image data, stores the encoded image data in a frame memory, and then decodes (restores) the encoded image data read from the frame memory. The converted image data is used as image data one frame before. However, since the image data undergoes encoding and decoding to cause deterioration (compression error) in the image data, encoding and decoding are not performed particularly when the image data is a still image. There is a disadvantage that the current frame and the image data of the previous frame that has been encoded and decoded do not match, and the image data of the current frame is unintentionally corrected.

  As a technique for preventing such unintentional correction of image data of the current frame, compression is performed by encoding and decoding not only the image data of the previous frame but also the image data of the current frame. A technique for compensating for the difference between the current frame and the image data of the previous frame due to an error has been proposed.

  For example, Patent Literature 1 below determines a correction amount based on image data obtained by encoding and decoding image data of the current frame, and image data obtained by encoding and decoding image data of the previous frame, and An image processing circuit for driving a liquid crystal that corrects the image data of the current frame based on the determined correction amount is disclosed. Specifically, the liquid crystal drive image processing circuit decodes the encoded image data output by the encoding unit that outputs encoded image data corresponding to the image of the current frame, and the encoding unit. Accordingly, decoding means for outputting first decoded image data corresponding to the image data of the current frame, and delay means for delaying the encoded image data output by the encoding means for a period corresponding to one frame Decoding means for outputting second decoded image data corresponding to image data one frame before the current frame by decoding the encoded image data output by the delay means; and Correction data for outputting correction data for correcting the gradation value of the image of the current frame based on the first decoded image data and the second decoded image data It comprises a raw device, and correcting means for correcting the image data representing an image of the current frame based on the correction data.

  Further, for example, Patent Document 2 below discloses an image processing circuit that determines whether image data is a still image or a moving image, and performs overdrive processing when the image data is a moving image as a result of the determination. To do. Specifically, the image processing circuit includes: quantization means for outputting quantized data quantized with a predetermined threshold for image data input to the liquid crystal display; and the image data is in the vicinity of the threshold Threshold neighborhood determination means for judging whether or not the threshold value, and output as threshold neighborhood judgment data, the quantized data and threshold neighborhood judgment data of the current frame, the quantized data and threshold neighborhood judgment data of the previous frame Based on the above, the moving image still image determining means for determining whether the image data of the current frame is a still image or a moving image, and when the moving image still image determining means determines that the image is a moving image, the overdrive processing is performed. Overdrive processing means for outputting image data.

JP 2004-139095 A JP 2007-25528 A

  The conventional image processing circuit for driving a liquid crystal disclosed in Patent Document 1 uses image data that has been encoded and decoded (that is, color components are thinned out in the spatial direction) for determining the correction amount. ing. Accordingly, the correction amount determined by the liquid crystal driving image processing circuit is thinned out in the spatial direction. When the correction is performed on the image data of the current frame with the correction amount thinned out in the spatial direction, the image data of the output frame has a slight gradation blur in the spatial direction. Such gradation blur is not noticeable when the gradation of the image data of the output frame is near the middle of white and black, but becomes noticeable when the gradation of the image data of the output frame is close to white and black, This results in a visually undesirable effect for the user of the image output apparatus.

  Further, the conventional image processing circuit disclosed in Patent Document 2 uses the image data of the previous frame that has been encoded and decoded and the image data of the current frame that has not been encoded and decoded, and the correction amount. Therefore, the correction amount is a value including a compression error of image data one frame before. When the gradation of the image data of the output frame is in the vicinity of white and black, the value of the correction amount is less affected by the image data of the previous frame due to the LUT characteristics, so the compression error included in the correction amount does not matter. When the gradation of the image data of the output frame is near the middle between white and black, the value of the correction amount is easily affected by the image data of the previous frame. For this reason, the image data of the output frame becomes a distorted image due to the influence of the compression error.

  Accordingly, an object of the present invention is to provide an image output system capable of performing overdrive processing while maintaining the image quality of output image data even when image data used for overdrive processing is deteriorated. .

  In addition, the present invention is based on the determination whether the image data is a still image or a moving image while maintaining the image quality of the output image data even when the image data used for the overdrive processing is deteriorated. An object of the present invention is to provide an image output system capable of performing drive processing.

  The present invention for solving the above problems includes the following technical features or invention specific matters.

  That is, the present invention according to a certain aspect is an image output device that outputs image data, and is based on an input signal including the image data transmitted from the outside, and a delay delayed with respect to the deteriorated signal Based on the result of determination by the determination unit, a signal conversion unit that generates a deterioration signal, a determination unit that determines whether a difference between the input signal and the delayed deterioration signal is smaller than a predetermined threshold, A selection circuit that selects one of the input signal and the deteriorated signal as a selection input signal, and the input signal is corrected based on the selection input signal and the delayed deteriorated signal, and the result of the correction is obtained. An image output apparatus comprising: a correction unit that outputs an output signal.

  Thus, the image output apparatus selects either the deteriorated signal or the delayed deteriorated signal as the selection input signal according to the magnitude of the difference between the input signal and the delayed deteriorated signal, and inputs based on the selected input signal and the delayed deteriorated signal. Since the signal is corrected, the overdrive process can be performed by appropriately correcting the input signal so that the image data is not deteriorated.

  Here, the signal conversion unit decodes at least one encoding unit that encodes the input signal, the input signal encoded by the at least one encoding unit, and converts the decoded input signal into A first decoding unit that outputs the degraded signal; a delay unit that delays an input signal encoded by the at least one encoding unit; and the encoded input signal delayed by the delay unit. A second decoding unit that decodes and outputs the decoded input signal as the delayed deterioration signal.

  As a result, the image output apparatus can generate a deteriorated signal by encoding and decoding the input signal, encode the input signal, delay the encoded input signal, and perform the delayed encoding. A delayed deterioration signal can be generated by decoding the input signal.

  The correction unit determines a correction amount for the input signal based on the selection input signal and the delay deterioration signal, and corrects the input signal based on the determined correction amount. Also good.

  As a result, the image output apparatus determines the correction amount for the input signal based on the selected input signal and the delay deterioration signal, and therefore can appropriately determine the correction amount for the input signal and appropriately correct the input signal. it can.

  The selection circuit selects the deterioration signal as the selection input signal when the difference between the input signal and the delay deterioration signal is smaller than the predetermined threshold, and the difference between the input signal and the delay deterioration signal. May not be smaller than the predetermined threshold, the input signal may be selected as the selection input signal.

  Thus, the image output apparatus can appropriately select the selected input signal from either the input signal or the deteriorated signal based on the difference between the input signal and the delayed deteriorated signal.

  The image output device further includes a still image determination unit that determines whether image data included in the input signal is a still image based on a difference between the deterioration signal and the delay deterioration signal, and the correction The unit may correct the input signal based on the input signal, the selection input signal, the delay deterioration signal, and a result of determination by the still image determination unit.

  Thus, the image output apparatus determines whether the image data is a still image based on the difference between the deteriorated signal and the delayed deteriorated signal, and corrects the input signal based on the determination result. Unintentional correction to the input signal can be prevented.

  Here, the correction unit may output the input signal as the output signal when there is no difference between the deterioration signal and the delay deterioration signal.

  Thereby, when there is no difference between the deteriorated signal and the delayed deteriorated signal (that is, when the image data is a still image), the image output device outputs the input signal as an output signal to the input signal. It is possible to prevent correction.

  Furthermore, the present invention according to another aspect is an image data output method in an image output apparatus, which is delayed with respect to a deterioration signal and the deterioration signal based on an input signal including the image data transmitted from the outside. Generating a delayed deterioration signal, and when a difference between the input signal and the delay deterioration signal is smaller than a predetermined threshold, determining a correction amount based on the deterioration signal and the delay deterioration signal; When the difference between the input signal and the delay deterioration signal is not smaller than a predetermined threshold, the correction amount is determined based on the input signal and the delay deterioration signal, and the input based on the determined correction amount A method for outputting image data, including correcting and outputting a signal.

  As a result, the image output apparatus generates a deteriorated signal and a delayed deteriorated signal, selects either the deteriorated signal or the delayed deteriorated signal as the selected input signal according to the difference between the input signal and the delayed deteriorated signal, and selects the selected signal. Since the correction amount for the input signal is determined based on the input signal and the delay deterioration signal, and the input signal is corrected based on the determined correction amount, the input signal is appropriately corrected so that the image data is not deteriorated. Overdrive processing can be performed.

  Furthermore, the present invention according to another aspect is an image data output method in an image output apparatus, which is delayed with respect to a deterioration signal and the deterioration signal based on an input signal including the image data transmitted from the outside. Generating a delayed deterioration signal, and when a difference between the input signal and the delay deterioration signal is smaller than a predetermined threshold, determining a correction amount based on the deterioration signal and the delay deterioration signal; When the difference between the input signal and the delay deteriorated signal is not smaller than a predetermined threshold, determining the correction amount based on the input signal and the delay deteriorated signal; and between the deteriorated signal and the delay deteriorated signal When there is a difference between them, an image data output method includes: correcting and outputting an input signal based on the determined correction amount.

  As a result, the image output apparatus generates a deteriorated signal and a delayed deteriorated signal, selects either the deteriorated signal or the delayed deteriorated signal as the selected input signal according to the difference between the input signal and the delayed deteriorated signal, and selects the selected signal. A correction amount for the input signal is determined based on the input signal and the delay deterioration signal, and the correction amount determined when there is a difference between the deterioration signal and the delay deterioration signal (that is, the image data is a moving image). Since the input signal is corrected based on this, when the image data is a moving image, the input signal is appropriately corrected so that the image data does not deteriorate, and the overdrive process can be performed.

  According to the present invention, the image output system can perform the overdrive process while maintaining the image quality of the output image data even when the image data used for the overdrive process is deteriorated.

  According to the present invention, the image output system is either a still image or a moving image while maintaining the image quality of the output image data even when the image data used for the overdrive process is deteriorated. Based on this determination, the overdrive process can be performed.

  Other technical features, objects, effects, and advantages of the present invention will become apparent from the following embodiments described with reference to the accompanying drawings.

It is a figure which shows an example of schematic structure of the image output system which concerns on one Embodiment of this invention. It is a conceptual diagram which shows the detail of the encoding in the encoding part of the image output device which concerns on one Embodiment of this invention. 6 is a flowchart showing an operation of overdrive processing in the image output apparatus according to the embodiment of the present invention. It is a figure which shows the correction amount of the gradation with respect to the image display element in the image output device which concerns on one Embodiment of this invention. It is a figure which shows the correction amount of the gradation with respect to the image display element in the image output device which concerns on one Embodiment of this invention. It is a figure which shows the correction amount of the gradation with respect to the image display element in the image output device which concerns on one Embodiment of this invention. It is a figure which shows the correction amount of the gradation with respect to the image display element in the image output device which concerns on one Embodiment of this invention. It is a figure which shows the other example of a structure of the signal conversion part in the image output system which concerns on one Embodiment of this invention. It is a figure which shows the other example of a structure of the signal conversion part in the image output system which concerns on one Embodiment of this invention. It is a figure which shows the other example of a structure of the signal conversion part in the image output system which concerns on one Embodiment of this invention. It is a figure which shows the other example of a structure of the signal conversion part in the image output system which concerns on one Embodiment of this invention. It is a figure which shows the other example of schematic structure of the image output system which concerns on one Embodiment of this invention. 6 is a flowchart showing an operation of overdrive processing in the image output apparatus according to the embodiment of the present invention.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating an example of a schematic configuration of an image output system according to an embodiment of the present invention. As shown in the figure, the image output system 1 according to the present embodiment includes, for example, a transmission device 10 and an image output device 20.

  The transmission device 10 is, for example, an eDP (embedded Display Port) source device (for example, a personal computer, a set-top box, or a control board), but is not limited thereto. The transmission device 10 generates an input signal IN including image data to be displayed in accordance with a standard such as the NTSC method or the sRGB method, and transmits the signal to the image output device 20. In the following, it is assumed that the input signal IN is an RGB signal and includes information on a red color component, a blue color component, and a green color component.

  The image output device 20 is, for example, an eDP sink device (for example, a display or a projector), but is not limited thereto. The image output device 20 includes, for example, a signal conversion unit 21, a determination unit 22, a selection circuit 23, a correction unit 24, and a display unit 25.

  The signal conversion unit 21 performs signal conversion on the input signal IN output from the transmission apparatus 10, and generates a deterioration signal D_IN and a delay deterioration signal DD_IN. In this example, the signal conversion unit 21 includes a deterioration signal generation unit 21A that generates a deterioration signal D_IN and a delay deterioration signal generation unit 21B that generates a delay deterioration signal DD_IN.

  Specifically, the deterioration signal generation unit 21A generates the deterioration signal D_IN by performing decoding immediately after encoding the input signal IN, and outputs the deterioration signal D_IN to the selection circuit 23. The degraded signal generation unit 21A includes, for example, an encoding unit 211A and a decoding unit 212A. On the other hand, the delay deterioration signal generation unit 21B encodes the input signal IN, delays the encoded signal, and then decodes the delayed signal to decode the delay deterioration signal DD_IN. And outputs the signal to the determination unit 22 and the correction unit 24. The delay degradation signal generation unit 21B includes, for example, an encoding unit 211B, a decoding unit 212B, and a delay unit 213.

  The encoding units 211A and 211B perform encoding on the input signal IN transmitted from the transmission device 10. Specifically, the encoding units 211A and 211B encode the input signal IN, for example, by performing a process of thinning out color component information in the spatial direction on the input signal IN transmitted from the transmission device 10. . Alternatively, the encoding units 211A and 211B may encode the input signal IN by performing processing (that is, quantization) for thinning out information on color components by an arbitrary lower bit with respect to the input signal IN. Alternatively, the encoding units 211A and 211B encode the input signal IN by collectively expressing data that appears continuously, assigning a short code to data having a high appearance probability (ie, entropy compression), and the like. May be. The signal encoded by the encoding unit 211A is output to the decoding unit 212A, and the signal encoded by the encoding unit 211B is output to the delay unit 213. Encoding sections 211A and 211B may typically have the same circuit configuration.

  The decoding units 212A and 212B perform decoding on the encoded input signal. Specifically, the decoding unit 212A generates a degraded signal D_IN by decoding the encoded input signal output from the encoding unit 211A, and inputs this signal to the selection circuit 23. Output to terminal A1. Also, the decoding unit 212B generates a delayed deterioration signal DD_IN by decoding the encoded input signal output from the delay unit 213, and sends the signal to the determination unit 22 and the correction unit 24. Output. Decoding sections 212A and 212B may typically have the same circuit configuration.

  The delay unit 213 delays the encoded input signal output from the encoding unit 211B, for example, by one frame. The delay unit 213 is, for example, a storage device such as a DRAM or a frame memory or a buffer, but is not limited thereto. The delay unit 213 outputs the delayed input signal to the decoding unit 212B.

The determination unit 22 determines whether or not the difference between the input signal IN output from the transmission device 10 and the delay deterioration signal DD_IN output from the signal conversion unit 21 is smaller than a predetermined threshold value. Specifically, the determination unit 22 calculates a difference between the input signal IN and the delay deterioration signal DD_IN as shown in the following Equation 1, and determines whether the difference is smaller than a predetermined threshold.
| Input signal-delayed degradation signal | <Threshold value <Equation 1>
When the determination unit 22 determines that the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than a predetermined threshold, the state of the selection signal SEL is set to “1” and the signal is selected by the selection terminal SL of the selection circuit 23. On the other hand, when it is determined that the difference between the input signal IN and the delay degradation signal DD_IN is not smaller than a predetermined threshold, the state of the selection signal SEL is set to “0” and the signal is selected by the selection terminal SL of the selection circuit 23. Output to. The predetermined threshold is, for example, a value such as 30, 32, 34, 36, 38, or 40, but is not limited thereto, and a predetermined value corresponding to the characteristics of the image output apparatus 20 can be selected.

  The selection circuit 23 is a multiplexer, for example, but is not limited thereto. Based on the selection signal SEL output from the determination unit 22, the selection circuit 23 uses either the input signal IN transmitted from the transmission device 10 or the deterioration signal D_IN output from the signal conversion unit 21 as the selection input signal SEL_IN. The selected signal is output to the correction unit 24. Specifically, when the state of the selection signal SEL is “0”, the selection circuit 23 outputs the input signal IN to the correction unit 24 as the selection input signal SEL_IN. On the other hand, when the state of the selection signal SEL is “1”, the selection circuit 23 outputs the deterioration signal D_IN to the correction unit 24 as the selection input signal SEL_IN.

The correcting unit 24 includes, for example, an LUT 241. In the LUT 241, a correction amount determined based on the selection input signal SEL_IN and the delay deterioration signal DD_IN is stored in advance. Based on the selection input signal SEL_IN output from the selection circuit 23 and the delay deterioration signal DD_IN output from the signal conversion unit 21, the correction unit 24 uses the correction amount stored in advance in the LUT 241 for overdrive processing. A correction amount is determined, the input signal IN transmitted from the transmission device 10 is corrected based on the determined correction amount, and output to the display unit 25 as an output signal OUT. Table 1 below is a table showing an example of a correspondence relationship between the selection input signal SEL_IN and the delay deterioration signal DD_IN and the correction amount for the input signal IN.

Note that the correction unit 24 may be configured using an LUT that stores the result of performing correction based on the correction amount on the input signal IN. Table 2 below is a table showing an example of a correspondence relationship between the selection input signal SEL_IN, the delay deterioration signal DD_IN, and the correction result for the input signal IN. When the LUT 241 stores the correction result, the correction unit 24 outputs the correction result to the display unit 25 as the output signal OUT.

  The display unit 25 is, for example, a liquid crystal display panel or an organic electroluminescence display panel, but is not limited thereto. The display unit 25 includes image display elements arranged in a matrix, and displays an image according to the output signal OUT by applying the output signal OUT output from the correction unit 24 to the corresponding image display element. In this example, the display unit 25 is provided in the image output device 20, but is not limited thereto, and the display unit 25 may be provided separately from the image output device 20. .

  The image output apparatus 20 configured as described above generates a deteriorated signal D_IN by encoding and decoding the input signal IN, and encodes and delays the input signal IN and then decodes it. As a result, the delay deterioration signal DD_IN is generated. The image output device 20 determines whether or not the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than a predetermined threshold, and based on the determination result, either the input signal IN or the deterioration signal D_IN is determined. Select and output as selection signal SEL_IN. The image output device 20 determines a correction amount based on the selection input signal SEL_IN and the delay deterioration signal DD_IN, corrects the input signal IN based on the determined correction amount, and outputs the correction signal as an output signal OUT.

  As a result, the image output device 20 selects the signal to be used for determining the correction amount according to the difference between the input signal IN and the delay deterioration signal DD_IN, so that the image data used for the overdrive process is deteriorated. Even in such a case, it is possible to appropriately determine the correction amount for the input signal IN and perform the overdrive process without degrading the image quality of the image data.

  FIG. 2 is a conceptual diagram showing details of encoding in the encoding unit of the image output apparatus according to the embodiment of the present invention. Specifically, FIG. 2 shows the correspondence between the display unit 25 and each signal of the encoding unit 211 for showing details of encoding in the encoding unit 211 of the image output apparatus 20 according to the embodiment of the present invention. It is a figure which shows a relationship. In the figure, the display unit 25 includes four image display elements P (x, y) to P (x + 1, y + 1). In the figure, an input signal IN includes information on red color components R0 to R3 corresponding to the image display elements P (x, y) to P (x + 1, y + 1), and the image display element P (x, y ) To P (x + 1, y + 1) information corresponding to green color components G0 to G3, and blue color components B0 to B3 corresponding to image display elements P (x, y) to P (x + 1, y + 1), respectively. Information.

  Referring to FIG. 5A, the encoding unit 211 converts the input signal IN from the RGB system to the YUV system to generate the input signal IN ′. Here, the YUV method expresses the color component of a signal by luminance (that is, luminance information Y), a difference between luminance and a blue component (that is, color difference information U), and a difference between luminance and a red component (that is, color difference information V). It is a method to do. The input signal IN ′ converted into the YUV format by the encoding unit 211 includes information on luminance information Y0 to Y3 corresponding to the image display elements P (x, y) to P (x + 1, y + 1), and the image display element P. Color difference information U0 to U3 corresponding to (x, y) to P (x + 1, y + 1), respectively, and color difference information V0 to V3 corresponding to image display elements P (x, y) to P (x + 1, y + 1), respectively. Information.

  The encoding unit 211 performs a process of thinning out the color difference information U and V in the horizontal direction on the display unit 25 with respect to the input signal IN ′. Specifically, the encoding unit 211 calculates, for example, an average value of the color difference information U0 and U1 of the image display elements P (x, y) and P (x + 1, y), and displays the result U0 ′ of the calculation as an image. New color difference information of the elements P (x, y) and P (x + 1, y) is used. Also, the encoding unit 211 calculates, for example, an average value of the color difference information U2 and U3 of the image display elements P (x, y + 1) and P (x + 1, y + 1), and the calculation result U2 ′ is calculated as the image display element P ( x, y + 1) and new color difference information of P (x + 1, y + 1).

  Similarly, the encoding unit 211 calculates, for example, an average value of the color difference information V0 and V1 of the image display elements P (x, y) and P (x + 1, y), and uses the calculation result V0 ′ as the image display element P. The new color difference information is (x, y) and P (x + 1, y). Also, the encoding unit 211 calculates, for example, an average value of the color difference information V2 and V3 of the image display elements P (x, y + 1) and P (x + 1, y + 1), and the calculation result V2 ′ is calculated as the image display element P ( x, y + 1) and new color difference information of P (x + 1, y + 1). Then, the encoding unit 211 outputs the input signal IN ′ obtained by thinning out the color difference information U and V as the input signal IN ″.

  FIG. 4B is a conceptual diagram showing details of encoding when the color difference information U and V are thinned out not only in the horizontal direction but also in the vertical direction. Referring to FIG. 5B, the encoding unit 211 converts the input signal IN from the RGB system to the YUV system, and generates the input signal IN ′.

  The encoding unit 211 performs a process of thinning out the color difference information U and V in the horizontal direction and the vertical direction in the display unit 25 with respect to the input signal IN ′. Specifically, the encoding unit 211 calculates, for example, an average value of the color difference information U0 to U3 of the image display elements P (x, y) to P (x + 1, y + 1), and uses the calculation result U0 ″ as an image. New color difference information of the display elements (x, y) to P (x + 1, y + 1) is used.

  Similarly, the encoding unit 211 calculates, for example, an average value of the color difference information V0 to V3 of the image display elements P (x, y) to P (x + 1, y + 1), and displays the calculation result V0 ″ as an image. New color difference information of the elements P (x, y) to P (x + 1, y + 1) is used. Then, the encoding unit 211 outputs the input signal IN ′ obtained by thinning out the color difference information U and V as the input signal IN ″.

  FIG. 3 is a flowchart showing an operation of overdrive processing in the image output apparatus according to the embodiment of the present invention. As shown in the figure, the image output apparatus 20 first encodes the input signal IN transmitted from the transmission apparatus 10, stores the encoded input signal, and stores the stored input. By performing decoding on the signal, a delayed deterioration signal DD_IN is generated, and by performing encoding and decoding on the input signal IN, a deterioration signal D_IN is generated (S301).

  The image output apparatus 20 determines whether or not the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than a predetermined threshold according to Equation 1 (S302). When the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than the predetermined threshold (Yes in S302), the image output device 20 determines the correction amount based on the deterioration signal D_IN and the delay deterioration signal DD_IN (S303). On the other hand, when the difference between the input signal IN and the delay deterioration signal DD_IN is not smaller than the predetermined threshold (No in S302), the image output device 20 determines the correction amount based on the input signal IN and the delay deterioration signal DD_IN ( S304).

  Subsequently, the image output apparatus 20 performs correction on the input signal IN based on the determined correction amount, and generates an output signal OUT (S305). The image output apparatus 20 displays an image based on the generated output signal OUT (S306), and ends the overdrive processing operation.

  As described above, the image output device 20 determines the selection input signal SEL_IN used to determine the correction amount based on the magnitude of the difference between the input signal IN and the delay deterioration signal DD_IN. Even when the image data used for the processing is deteriorated, it is possible to appropriately determine the correction amount for the input signal IN and perform the overdrive processing without deteriorating the image quality of the image data.

[Operation when the difference between the input signal IN and the delay degradation signal DD_IN is not smaller than a predetermined threshold value]
4 and 5 are diagrams showing the correction amount of the gradation for the image display element in the image output apparatus according to the embodiment of the present invention. In the figure, for comparison, the amount of correction by a conventional image output apparatus (hereinafter referred to as “first conventional apparatus”) configured to always perform correction using the deterioration signal D_IN and the delay deterioration signal DD_IN is indicated by a broken line arrow. In addition, the predetermined threshold value is 36. Further, an example of the gradation value of each signal corresponding to each image display element (see FIG. 2) in FIGS. It is shown in Table 3.

  Referring to FIG. 4 and Table 3, the gradation values of the delayed deterioration signal DD_IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 90, 90, 98, and 98, respectively. The gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 8, 12, 16 and 20, respectively. That is, the gradation value of the input signal IN is greatly reduced with respect to the gradation value of the delay deterioration signal DD_IN. According to Table 2, when the gradation value of the delay deterioration signal DD_IN is sufficiently large and the gradation value of the selection input signal SEL_IN is sufficiently small, the gradation value of the output signal OUT is preferably 0. In such a case, the correction amount is not easily affected by the difference in gradation between the delay deterioration signal DD_IN and the selection input signal SEL_IN.

  Since the first conventional apparatus always uses the deterioration signal D_IN and the delay deterioration signal DD_IN for determining the correction amount, the level of the deterioration signal D_IN corresponding to the image display elements P (x, y) to P (x + 3, y). The correction amount is determined so that the adjustment values 10, 10, 18 and 18 are all zero. Therefore, the first conventional apparatus determines the correction amount to be −10, −10, −18, and −18.

  On the other hand, the image output apparatus 20 determines the selection input signal SEL_IN used for determining the correction amount based on whether or not the difference between the delay degradation signal DD_IN and the input signal IN is smaller than a predetermined threshold. The gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 8, 12, 16, and 20, respectively, and the image display elements P (x, y) to P ( Since the gradation values of the delay deterioration signal DD_IN corresponding to x + 3, y) are 90, 90, 98, and 98, respectively, the image output device 20 uses the image display elements P (x, y) to P (x + 3, y). ) And the delay deterioration signal DD_IN are all determined not to be smaller than a predetermined threshold, and the input signal IN is selected as the selection input signal SEL_IN. The image output device 20 determines the correction amount so that the gradation values 8, 12, 16, and 20 of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) are all 0. To do. Therefore, the image output apparatus 20 determines the correction amount to be -8, -12, -16, and -20.

  Next, referring to FIG. 5 and Table 3, the first conventional apparatus uses the determined correction amounts −10, −10, −18, and −18 to the image display elements P (x, y) to P (x + 3, y) is corrected by subtracting from the gradation values 8, 12, 16 and 20 of the input signal IN corresponding to y) (note that the value which is 0 or less as a result of the calculation is 0), and generates the output signal of the conventional device To do. The first conventional apparatus determines the gradation value of the output signal of the conventional apparatus corresponding to the image elements P (x, y) to P (x + 3, y) as 0, 2, 0, and 2. Therefore, when there is a large difference in the gradation value between the input signal IN and the delayed deterioration signal DD_IN, the first conventional device includes an error due to the difference between the deterioration signal D_IN and the input signal IN. The tone value of the signal deviates from the originally intended tone value. As a result, in the first conventional apparatus, when the color component is thinned out in the horizontal direction, the influence of the error due to the difference between the deterioration signal D_IN and the input signal IN appears on the display unit 25 in a vertical stripe shape. This results in an undesirable visual effect for the user of one conventional device.

  On the other hand, the image output apparatus 20 uses the determined correction amounts −8, −12, −16, and −20 as the gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y). Correction is performed by subtracting from 8, 12, 16 and 20, and an output signal OUT is generated. The image output device 20 determines the gradation values of the output signal OUT corresponding to the image display elements P (x, y) to P (x + 3, y) as 0, 0, 0, and 0. Therefore, the image output apparatus 20 is caused by the difference between the deterioration signal D_IN and the input signal IN in the gradation value of the output signal OUT even when there is a large difference in the gradation value between the input signal IN and the delay deterioration signal DD_IN. An error signal is not included, and the output signal OUT having the originally intended gradation value can be generated.

[Operation when the difference between the input signal IN and the delay degradation signal DD_IN is smaller than a predetermined threshold value]
6 and 7 are diagrams showing the correction amount of the gradation of the image display element in the image output apparatus according to the embodiment of the present invention. For comparison, the amount of correction by a conventional image output apparatus (hereinafter referred to as “second conventional apparatus”) configured to always perform correction using the input signal IN and the delayed deterioration signal DD_IN in the drawing. Is indicated by a dashed arrow. Further, it is assumed that the predetermined threshold is 36. In addition, an example of the gradation value of each signal corresponding to each image display element (see FIG. 2) in FIGS. 6 and 7 is shown in Table 4 below.

  Referring to FIG. 6 and Table 4, the gradation values of the delayed deterioration signal DD_IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 90, 90, 98, and 98, respectively. The gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 78, 82, 86, and 90, respectively. The gradation value of the input signal IN is slightly lower than the gradation value of the delay deterioration signal DD_IN. According to Table 2, when the gradation value of the delay deterioration signal DD_IN is close to the gradation value of the selection input signal SEL_IN, the gradation value of the output signal OUT is the level of the delay deterioration signal DD_IN and the selection input signal SEL_IN. Susceptible to key differences.

  Since the second conventional apparatus always uses the input signal IN and the delay deterioration signal DD_IN for determining the correction amount, the scale of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) is used. Correction is performed based on the gradation values 78, 82, 86, and 90 and the gradation values 90, 90, 98, and 98 of the delay deterioration signal DD_IN corresponding to the image display elements P (x, y + 1) to P (x + 3, y). Determine the amount. Therefore, the second conventional apparatus determines the correction amount to be −15, −6, −14, and −5 from Table 1. As described above, the second conventional apparatus determines the correction amount based on the delay deterioration signal DD_IN including the compression error and the input signal IN not including the compression error, thereby including the compression error in the determined correction amount. I understand that.

  On the other hand, the image output apparatus 20 determines the selection input signal SEL_IN used for determining the correction amount based on whether or not the difference between the delay deterioration signal DD_IN and the input signal IN is smaller than a predetermined threshold value. The gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y) are 78, 82, 86 and 90, respectively, and the image display elements P (x, y) to P ( Since the gradation values of the delay deterioration signal DD_IN corresponding to x + 3, y) are 90, 90, 98, and 98, respectively, the image output device 20 uses the image display elements P (x, y) to P (x + 3, y). ) And the delayed deterioration signal DD_IN are all determined to be smaller than a predetermined threshold, and the deterioration signal D_IN is selected as the selection input signal SEL_IN. The image output apparatus 20 includes gradation values 80, 80, 88, and 88 of the deterioration signal D_IN corresponding to the image display elements P (x, y) to P (x + 3, y), and a gradation value 90 of the delay deterioration signal DD_IN. , 90, 98, and 98, the correction amount is determined. Therefore, the image output apparatus 20 determines the correction amounts to -11, -11, -10, and -10. Since the image output apparatus 20 uses the delay deterioration signal DD_IN and the deterioration signal D_IN including a compression error in determining the correction amount, it is not necessary to include the compression error in the correction amount to be determined by canceling the compression error. .

  Referring to FIG. 7 and Table 4, the second conventional apparatus applies the determined correction amounts −15, −6, −14 and −5 to the image display elements P (x, y) to P (x + 3, y). Correction is performed by subtracting from the corresponding gradation values 78, 82, 86 and 90 of the input signal IN to generate the output signal of the second conventional device. The second conventional apparatus determines the gradation values of the output signals of the conventional apparatus corresponding to the image elements P (x, y) to P (x + 3, y) to 63, 76, 72, and 85. Therefore, in the second conventional device, when the gradation values of the input signal IN and the delayed deterioration signal DD_IN are close, the gradation value of the generated output signal includes the compression error of the delayed deterioration signal DD_IN, so that the output signal Therefore, the tone value is different from the originally intended tone value. As a result, in the second conventional apparatus, when the color component is thinned out in the horizontal direction, the influence of the compression error of the delay deterioration signal DD_IN appears on the display unit 25 in a vertical stripe shape, and the user of the second conventional apparatus This results in an unfavorable visual effect.

  On the other hand, the image output apparatus 20 uses the determined correction amounts -11, -11, -10 and -10 as the gradation values of the input signal IN corresponding to the image display elements P (x, y) to P (x + 3, y). Correction is performed by subtracting from 78, 82, 86, and 90, and an output signal OUT is generated. The image output device 20 determines the gradation values of the output signal OUT corresponding to the image display elements P (x, y) to P (x + 3, y) as 67, 71, 76, and 80. Therefore, the image output apparatus 20 does not include the compression error of the delayed deterioration signal DD_IN in the gradation value of the output signal OUT, even when the gradation values of the input signal IN and the delay deterioration signal DD_IN are close to each other. A tone output signal OUT can be generated.

  As described above, the image output apparatus 20 has a large difference between the input signal IN and the delay deterioration signal DD_IN, and the difference in gradation between the selection input signal SEL_IN and the delay deterioration signal DD_IN does not significantly affect the correction amount. Prevents the error due to the difference between the degradation signal D_IN and the input signal IN from being included by selecting the input signal IN as the selection input signal SEL_IN. On the other hand, when the difference between the input signal IN and the delay deterioration signal DD_IN is small and the difference in gradation between the selection input signal SEL_IN and the delay deterioration signal DD_IN greatly affects the correction amount, the image output device 20 has a deterioration signal. By selecting D_IN as the selection input signal SEL_IN, the output signal OUT is prevented from including a compression error. Thereby, even when the image data used for the overdrive process is deteriorated, the image output apparatus 20 appropriately determines the correction amount for the input signal IN, and performs the overdrive process without degrading the image quality of the image data. It can be carried out.

  FIG. 8 is a diagram illustrating another example of the configuration of the signal conversion unit in the image output system according to the embodiment of the present invention. As shown in the figure, the signal conversion unit 821 has a configuration in which one encoding unit 211 is shared. That is, in the signal conversion unit 821, the encoding unit 211 encodes the input signal IN output from the transmission apparatus 10, outputs the encoded signal to the decoding unit 212A, and outputs it to the delay unit 213. The other components in the signal conversion unit 821 are the same as those in the signal conversion unit 21 shown in FIG.

  FIG. 9 is a diagram illustrating another example of the configuration of the signal conversion unit in the image output system according to the embodiment of the present invention. As shown in the figure, the signal converter 921 includes a deteriorated signal generator 21A and a delayed deteriorated signal generator 921B.

  Delay degradation signal generation section 921B is configured by replacing encoding section 211A and delay section 213 with respect to delay degradation signal generation section 21B. The delay deterioration signal generation unit 921B delays the input signal IN output from the transmission apparatus 10 by the delay unit 213, and encodes the delayed signal by the encoding unit 211B. The delay deterioration signal generation unit 921B generates a delay deterioration signal DD_IN by decoding the encoded signal by the decoding unit 212B. The other components in the signal conversion unit 921 are the same as those in the signal conversion unit 21 shown in FIG.

  FIG. 10 is a diagram illustrating another example of the configuration of the signal conversion unit in the image output system according to the embodiment of the present invention. As shown in the figure, the signal conversion unit 1021 is configured to delay the branch signal of the degraded signal D_IN output from the decoding unit 212. That is, the signal conversion unit 1021 encodes the input signal IN output from the transmission apparatus 10 by the encoding unit 211, and generates the deteriorated signal D_IN by decoding the encoded signal by the decoding unit 212. In addition, the signal conversion unit 1021 generates the delayed deterioration signal DD_IN by delaying the branch signal of the deterioration signal D_IN by the delay unit 213.

  FIG. 11 is a diagram illustrating another example of the configuration of the signal conversion unit in the image output system according to the embodiment of the present invention. As shown in the figure, the signal converter 1121 includes a deteriorated signal generator 1121A and a delayed deteriorated signal generator 1121B.

  The delay deterioration signal generation unit 1121B is configured by including a decoding unit 214 instead of the decoding unit 212B with respect to the delay deterioration signal generation unit 21B. The delay deterioration signal generation unit 1121B generates the delay deterioration signal DD_IN by performing the same operation as that of the delay deterioration signal generation unit 21B described above. In addition, the delay degradation signal generation unit 1121B degrades information regarding the compression error for the input signal IN generated by the decoding unit 214 by encoding and decoding the input signal IN by the encoding unit 211B and the decoding unit 214. Information signal D_INFO is generated and output to degradation signal generator 1121A. Here, the decoding unit 214 is information used when decoding the encoded signal (for example, information on the number of bits thinned out by the coding unit 211B or thinned out by the coding unit 211B). Information on the compression error with respect to the input signal IN is generated on the basis of the amount in the spatial direction.

  The signal conversion unit 1121 configured as described above uses the encoding unit 211A and the decoding unit 212A in the deterioration signal generation unit 1121A by using the deterioration information signal D_INFO generated in the delay deterioration signal generation unit 1121B. The degradation signal D_IN can be generated without doing so. Thereby, the signal conversion unit 1121 can generate the degradation signal D_IN with a smaller area than the signal conversion unit 21.

  FIG. 12 is a diagram illustrating another example of a schematic configuration of an image output system according to an embodiment of the present invention. As shown in the figure, the image output system 1A includes a correction unit 24A instead of the correction unit 24 in the image output system 1, and further includes a still image determination unit 26.

  The still image determination unit 26 determines whether the image data included in the input signal IN transmitted from the transmission device 10 is a still image, and outputs the determination result to the correction unit 24A as a still signal STATIC. Specifically, the still image determination unit 26 compares the deterioration signal D_IN output from the signal conversion unit 21 and the delay deterioration signal DD_IN, and determines whether there is a difference between the two signals. When there is a difference between the deterioration signal D_IN and the delay deterioration signal DD_IN, the still image determination unit 26 determines that the image data included in the input signal IN is not a still image, and sets the state of the still signal STATIC as “1”. The signal is output to the correction unit 24A. On the other hand, when there is no difference between the deterioration signal D_IN and the delay deterioration signal DD_IN, the still image determination unit 26 determines that the image data included in the input signal IN is a still image, and sets the state of the still signal STATIC to “0”. The signal is output to the correction unit 24A.

  The correction unit 24A determines whether or not to correct the input signal IN based on the still signal STATIC output from the still image determination unit 26. Specifically, the correction unit 24A determines the state of the still signal STATIC output from the still image determination unit 26. When the state of the static signal STATIC is “0”, the correction unit 24A outputs the input signal IN as the output signal OUT to the display unit 25. On the other hand, when the state of the static signal STATIC is “1”, the correction unit 24A corrects the input signal IN according to the selection input signal SEL_IN and the delay deterioration signal DD_IN, and outputs the output signal OUT to the display unit 25. . The constituent elements other than the correction unit 24A and the still image determination unit 26 are the same as those in the image output system 1, and thus the description thereof is omitted. In this example, the image output device 20A is configured to include the signal conversion unit 21; however, the image output device 20A is not limited to this, and the image output device 20A is not limited to the signal conversion unit 21 but the signal conversion unit 821. , 921, 1021 and 1121 may be included.

  In the image output apparatus 20A configured as described above, the still image determination unit 26 determines whether the image data included in the input signal IN is a still image, and the input signal IN is determined based on the determination result. Decide whether to perform overdrive processing. As a result, the image output device 20A prevents unintended correction when the state of the input signal IN is a still image, and the state of the input signal IN is a moving image, which is used for the overdrive process. Even when the image quality of the data is degraded, the overdrive process can be performed without appropriately degrading the image quality of the image data by appropriately determining the correction amount for the input signal IN.

  FIG. 13 is a flowchart showing the operation of overdrive processing in the image output apparatus according to the embodiment of the present invention. As shown in the figure, the image output device 20A first encodes the input signal IN transmitted from the transmission device 10, stores the encoded input signal, and stores the stored input signal. In addition to generating a delayed deterioration signal DD_IN by decoding the input signal IN, a deterioration signal D_IN is generated by encoding and decoding the input signal IN (S1301).

  The image output apparatus 20A determines whether or not the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than a predetermined threshold according to Equation 1 (S1302). When the difference between the input signal IN and the delay deterioration signal DD_IN is smaller than the predetermined threshold (Yes in S1302), the image output apparatus 20A determines the correction amount based on the deterioration signal D_IN and the delay deterioration signal DD_IN (S1303). On the other hand, when the difference between the input signal IN and the delay deterioration signal DD_IN is not smaller than the predetermined threshold (No in S1302), the image output device 20A determines the correction amount based on the input signal IN and the delay deterioration signal DD_IN ( S1304).

  The image output apparatus 20A determines whether there is a difference between the deterioration signal D_IN and the delay deterioration signal DD_IN (S1305). When the image output apparatus 20A determines that there is a difference between the deterioration signal D_IN and the delay deterioration signal DD_IN (Yes in S1305), the image output apparatus 20A performs correction on the input signal IN based on the determined correction amount, and outputs it. A signal OUT is generated (S1306). On the other hand, when the image output apparatus 20A determines that there is no difference between the deterioration signal D_IN and the delay deterioration signal DD_IN (No in S1305), the image output apparatus 20A outputs the input signal IN as the output signal OUT (S1307). The image output apparatus 20A displays an image based on the output signal OUT (S1308), and ends the overdrive processing operation.

  As described above, the image output device 20A determines whether or not the image data included in the input signal IN is a still image by the still image determination unit 26, and overdrives the input signal IN based on the determination result. Determine whether to perform processing. As a result, the image output device 20A prevents unintended correction when the state of the input signal IN is a still image, and the state of the input signal IN is a moving image, which is used for the overdrive process. Even when the image quality of the data is degraded, the overdrive process can be performed without appropriately degrading the image quality of the image data by appropriately determining the correction amount for the input signal IN.

  Each of the above embodiments is an example for explaining the present invention, and is not intended to limit the present invention only to these embodiments. The present invention can be implemented in various forms without departing from the gist thereof.

  For example, in the method disclosed herein, steps, operations, or functions may be performed in parallel or in a different order, as long as the results do not conflict. The steps, operations, and functions described are provided as examples only, and some of the steps, operations, and functions may be omitted and combined with each other without departing from the spirit of the invention. There may be one, and other steps, operations or functions may be added.

  Further, although various embodiments are disclosed in this specification, a specific feature (technical matter) in one embodiment is appropriately improved and added to another embodiment or the other implementation. Specific features in the form can be substituted, and such form is also included in the gist of the present invention.

  The present invention can be widely used in the field of equipment including an image output device and an image communication interface.

DESCRIPTION OF SYMBOLS 1 ... Image output system 10 ... Transmission apparatus 20 ... Image output apparatus 21, 821, 921, 1021, 1121 ... Signal conversion part 211 ... Encoding part 212, 214 ... Decoding part 213 ... Delay part 22 ... Determination part 23 ... Selection Circuit 24 ... Correction unit 241 ... LUT
25 ... Display unit 26 ... Still image determination unit

Claims (8)

An image output device that outputs image data,
Based on the input signal including the image data transmitted from the outside, the image display element position of the image data is delayed by one frame with respect to the deterioration signal corresponding to the input signal and including a compression error, and the deterioration signal. A signal conversion unit for generating a delayed deterioration signal including the compression error ;
A determination unit that determines whether or not a difference between the input signal and the delayed deterioration signal is smaller than a predetermined threshold;
A selection circuit that selects one of the input signal and the deteriorated signal as a selection input signal based on a result of the determination by the determination unit;
A correction unit that corrects the input signal based on the selection input signal and the delay deterioration signal, and outputs a result of the correction as an output signal;
An image output apparatus comprising: The signal converter is
At least one encoding unit for compressing and encoding the input signal;
A first decoding unit that decodes an input signal that has been compression- encoded by the at least one encoding unit and outputs the decoded input signal as the degraded signal;
A delay unit for delaying an input signal compression- encoded by the at least one encoding unit;
A second decoding unit that decodes the compression- encoded input signal delayed by the delay unit, and outputs the decoded input signal as the delayed degradation signal;
The image output apparatus according to claim 1, comprising:   The correction unit determines a correction amount for the input signal based on the selection input signal and the delay deterioration signal, and corrects the input signal based on the determined correction amount. The image output apparatus according to 1.   When the difference between the input signal and the delayed deterioration signal is smaller than the predetermined threshold, the selection circuit selects the deterioration signal as the selection input signal, and the difference between the input signal and the delay deterioration signal is The image output apparatus according to claim 1, wherein when the input signal is not smaller than a predetermined threshold, the input signal is selected as the selection input signal. A still image determination unit that determines whether image data included in the input signal is a still image based on a difference between the deterioration signal and the delay deterioration signal;
The correction unit corrects the input signal based on the input signal, the selection input signal, the delay deterioration signal, and a result of determination by the still image determination unit.
The image output apparatus according to claim 1.   The image output apparatus according to claim 5, wherein the correction unit outputs the input signal as the output signal when there is no difference between the deterioration signal and the delay deterioration signal. An image data output method in an image output apparatus,
Based on the input signal including the image data transmitted from the outside, the image display element position of the image data is delayed by one frame with respect to the deterioration signal corresponding to the input signal and including a compression error, and the deterioration signal. Generating a delayed deterioration signal including the compression error ;
When a difference between the input signal and the delay deterioration signal is smaller than a predetermined threshold, determining a correction amount based on the deterioration signal and the delay deterioration signal;
When the difference between the input signal and the delayed deterioration signal is not smaller than a predetermined threshold, determining the correction amount based on the input signal and the delayed deterioration signal;
Correcting and outputting the input signal based on the determined correction amount;
A method for outputting image data. An image data output method in an image output apparatus,
Based on the input signal including the image data transmitted from the outside, the image display element position of the image data is delayed by one frame with respect to the deterioration signal corresponding to the input signal and including a compression error, and the deterioration signal. Generating a delayed deterioration signal including the compression error ;
When a difference between the input signal and the delay deterioration signal is smaller than a predetermined threshold, determining a correction amount based on the deterioration signal and the delay deterioration signal;
When the difference between the input signal and the delayed deterioration signal is not smaller than a predetermined threshold, determining the correction amount based on the input signal and the delayed deterioration signal;
And outputting perform correction on the input signal based on the correction amount if there is a difference, determined between the deterioration signal and the delay degradation signal,
A method for outputting image data.