JP2017092699A - Image processing apparatus and image processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent uniform brightness correction from being performed on an image to be displayed in an image processing apparatus.SOLUTION: An image processing apparatus of this invention comprises: a luminance value calculating unit that, on the basis of a data signal related to an externally transmitted image, calculates luminance values of respective pixels represented by the data signal; a positional information generating unit that generates positional information in a predetermined frame on a display device for the pixels; a filling ratio calculating unit that calculates a predetermined filling ratio based on the luminance values for plural divided regions in the predetermined frame; a coefficient determining unit that determines a predetermined pixel coefficient of the pixels on the basis of the predetermined filling ratios and the luminance values of the pixels; a correction amount determining unit that determines a correction amount on the basis of a reference correction amount and the predetermined pixel coefficient based on the data signal; and an arithmetic unit that generates and outputs a corrected data signal by correcting the luminance values of the pixels according to the correction amount.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image processing apparatus and an image processing method, and more particularly to an image processing apparatus and an image processing method for correcting luminance unevenness and color unevenness of an image to be displayed on a display panel.

  A display device including a display panel such as a liquid crystal panel or an organic electroluminescence panel receives an image signal or a video signal supplied from the outside, and displays an image or video based on the image signal on the display panel. Such a display panel is typically composed of millions of pixels and is manufactured by a very fine manufacturing technique. However, as a practical problem, a so-called manufacturing variation (for example, non-uniformity in the thickness of a liquid crystal material) It is inevitable that uneven brightness or color occurs in the manufactured display panel due to variations in operating characteristics during voltage application.

  For this reason, the luminance unevenness characteristic of the display device is evaluated in advance, correction data is created, stored in a lookup table, and the luminance value of each pixel indicated by the image signal to be output to the display panel. In general, luminance unevenness and color unevenness of a displayed image are corrected by applying the correction data.

  For example, in the method for adjusting the luminance value of the display device disclosed in Patent Document 1 below, the luminance value of the display image of the display device is measured, and the measurement is performed corresponding to each image region obtained by dividing the display image into a plurality of regions. The luminance value is recorded in the first recording means, the luminance value correction amount for correcting the luminance value to the target luminance value set based on the measured luminance value, and the gradation value corresponding to the luminance value correction amount The relationship of the correction coefficient is recorded in the second recording means, and the gradation value of the display image is corrected for each image area based on the luminance value correction amount and the gradation value correction coefficient.

  Further, in relation to the brightness value adjustment method described above, by evaluating the brightness distribution in a predetermined area of the image based on the information on the brightness value of the image signal and correcting the brightness value of the image, the image There is known a technique for performing contour correction.

  For example, an image display device disclosed in Patent Document 2 below includes an image signal processing unit that performs scaling processing on an input image signal, an image contour correction unit that performs contour enhancement processing on the scaled image signal, and contour enhancement processing. And a display unit for displaying an image based on the image signal. In the image display device, the image contour correction unit indicates the degree of enhancement based on luminance value information in a predetermined area having a certain spread in both the horizontal and vertical directions centered on one pixel constituting the display unit. Edge enhancement processing is performed by selecting a coefficient.

JP 2007-114427 A JP 2008-197437 A

  Since the method for adjusting the luminance value of the display device disclosed in Patent Document 1 described above corrects the luminance value without considering whether or not the luminance unevenness is conspicuous, the correction of the luminance value is originally not desirable. The luminance value is uniformly corrected for the image signal indicating the image. As a result, there is a problem that the expression range related to the brightness of the display panel is unnecessarily lowered.

  Further, the image display device as disclosed in Patent Document 2 described above performs image edge enhancement processing by correcting the luminance value of the image based on the luminance value information of the image signal. No consideration was given to the luminance unevenness of the display device.

  Therefore, an object of the present invention is to provide an image processing apparatus and an image processing method capable of correcting the luminance value of each pixel while considering whether or not the luminance unevenness of the image to be displayed is conspicuous. .

  More specifically, the present invention determines a correction amount for the chromaticity of each color component of each pixel based on the characteristics of the image to be displayed (for example, a filled image), and based on the determined correction amount An object of the present invention is to provide an image processing apparatus and an image processing method capable of correcting the luminance value of each pixel by correcting the chromaticity of each color component of the pixel.

  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 processing device that processes a data signal related to an image transmitted from a transmission device and outputs the data signal to a display device. The image processing apparatus includes: a luminance value calculation unit that calculates a luminance value of each pixel indicated by the data signal based on the data signal; and the display of each pixel indicated by the data signal based on the data signal A position information generation unit that generates position information in a predetermined frame in the apparatus, and a predetermined fill rate for each of a plurality of divided regions in the predetermined frame based on the position information and the luminance value A fill rate calculation unit; a coefficient determination unit that determines a predetermined pixel coefficient of the pixel based on at least one of the plurality of predetermined fill rates and the luminance value of the pixel; and each color of the pixel indicated by the data signal A correction amount determination unit that determines a correction amount based on the chromaticity of the component and the position information reference correction amount and the predetermined pixel coefficient; The chromaticity of each color component of the data signal indicating the pixel to generate the correction data signal by correcting according to said correction amount, a calculation unit for outputting may comprise.

  Thus, the image processing apparatus determines a correction amount for the luminance value of each pixel to be displayed based on the image characteristics (for example, a filled image and / or its state), and based on the determined correction amount, The luminance value of the pixel can be corrected.

  Here, the filling rate calculation unit calculates a histogram for each divided region based on the luminance value of the pixel group in each divided region, and based on the calculated histogram, the pixel in each divided region. A ratio of pixels indicating the luminance value equal to or higher than a predetermined threshold in the group may be determined, and the ratio may be determined as the predetermined fill rate for each of the divided regions.

  As a result, the image processing apparatus corrects the chromaticity of each color component of each pixel to be displayed based on a predetermined fill rate, which is a ratio of pixels exhibiting a luminance value equal to or higher than a predetermined threshold in the pixel group. The luminance value of the pixel can be corrected by determining the amount and correcting the chromaticity of each color component of the pixel based on the determined correction amount.

  Further, the filling rate calculation unit determines a filling rate for each subdivision area based on a histogram for each subdivision area based on a luminance value of a pixel group in each subdivision area obtained by dividing each subdivision area. Then, the maximum value of the fill ratios for the determined subdivision areas can be determined as the predetermined fill ratio of the corresponding subareas.

  As a result, the image processing apparatus determines the fill rate for each subdivision area obtained by dividing each subarea, and determines a predetermined fill ratio for each subarea based on the determined fill ratio for each subdivision area. Therefore, by determining a correction amount for the chromaticity of each color component of each pixel to be displayed with higher accuracy, and correcting the chromaticity of each color component of the pixel based on the determined correction amount, The luminance value of can be corrected.

  Further, the coefficient determination unit determines a frame coefficient for each of the divided areas according to the size of a predetermined fill rate for each of the divided areas, and determines the predetermined coefficient according to the magnitude of the frame coefficient and the luminance value of the pixel. Pixel coefficients can be determined.

  Thereby, the image processing apparatus can determine a predetermined pixel coefficient according to the frame coefficient according to the magnitude of the filling rate and the magnitude of the luminance value of the pixel.

  Furthermore, the coefficient determination unit includes a boundary definition unit that defines a range of each divided region in the frame and a range in the vicinity of a boundary forming each divided region, and the coefficient determination unit belongs to the pixel The predetermined pixel coefficient is determined based on a smoothing coefficient determined based on the predetermined fill coefficient for the specific divided area when the pixel is not located in the vicinity of a boundary forming the specific divided area. Can do.

  Accordingly, the image processing apparatus determines a correction amount for the chromaticity of each color component of each pixel according to a pixel coefficient based on whether or not the pixel is located in the vicinity of a boundary forming a specific divided region, and the determination Based on the corrected amount, the luminance value of the pixel can be corrected by correcting the chromaticity of each color component of the pixel.

  In addition, when the pixel is located in the vicinity of the boundary that forms the specific divided region, the coefficient determination unit is configured to apply the predetermined fill to each of the specific divided region and the other divided regions that form the boundary. The predetermined pixel coefficient may be determined based on a smoothing coefficient based on the coefficient.

  Thereby, the image processing apparatus determines the predetermined pixel coefficient based on the smoothing coefficient based on the predetermined fill coefficient for each of the specific divided area and the other divided areas forming the boundary. Thus, it is possible to prevent a problem that the boundary between the divided areas becomes conspicuous due to different correction amounts.

  The image processing apparatus further includes a luminance unevenness information storage unit that stores information on the presence / absence of luminance unevenness in each of the divided regions, and the coefficient determination unit is configured to store luminance unevenness stored in the luminance unevenness information storage unit. The predetermined pixel coefficient may be determined based on information on presence / absence.

  As a result, the image processing apparatus can determine whether or not to correct the image based on the characteristics of the image (for example, whether the image is a filled image) and the luminance unevenness characteristic of the image processing apparatus. It becomes like this.

  Further, the coefficient determination unit may set the predetermined pixel coefficient to the same signal as the correction data signal and the data signal when a filling rate corresponding to a specific divided region to which the pixel belongs is less than a predetermined value. Can be determined to any value.

  As a result, the image processing apparatus can perform control so as not to perform correction on the divided areas whose fill rate is less than a predetermined value.

  Further, the coefficient determination unit is a divided region where the specific pixel to which the pixel belongs is a non-uniform luminance region, is adjacent to the specific divided region, has a non-uniform luminance, and a corresponding fill rate is a predetermined value. When there is no divided region that is equal to or greater than the value, the predetermined pixel coefficient may be determined to a value that makes the correction data signal and the data signal the same signal.

  As a result, the image processing apparatus can perform control so as not to perform correction on a divided region where the divided region with uneven brightness is not adjacent or a divided region where the filled divided region is not adjacent. .

  Furthermore, the present invention according to another aspect is an image processing method for processing a data signal related to an image transmitted from a transmission device. The image processing method calculates the luminance value of each pixel indicated by the data signal based on the data signal, and the luminance for each of a plurality of divided regions in a predetermined frame in the display device. Calculating a predetermined fill rate based on the value; determining a predetermined pixel coefficient of the pixel based on at least one of the plurality of the predetermined fill rates and a luminance value of the pixel; A correction data signal is determined by determining a correction amount based on a reference correction amount based on the data signal and the predetermined pixel coefficient, and correcting the chromaticity of each color component of the pixel indicated by the data signal according to the correction amount. Generating and outputting to the display device.

  Accordingly, the image processing apparatus determines a correction amount for the chromaticity of each color component of each pixel to be displayed based on the characteristics of the image (for example, a filled image and / or its state), and sets the determined correction amount to the determined correction amount. Based on this, the luminance value of the pixel can be corrected by correcting the chromaticity of each color component of the pixel.

  Here, the predetermined pixel coefficient is determined when the pixel is not located in the vicinity of a boundary that forms the specific divided region to which the pixel belongs, in the predetermined filling rate for the specific divided region. The method may include determining the predetermined pixel coefficient based on a smoothing coefficient determined based on the smoothing coefficient.

  As a result, the image processing apparatus determines the pixel coefficient by the smoothing coefficient based on the predetermined fill rate corresponding to the specific divided region to which the pixel belongs, and therefore the correction amount for the chromaticity of each color component of each pixel to be displayed Is determined with higher accuracy, and the luminance value of the pixel can be corrected by correcting the chromaticity of each color component of the pixel based on the determined correction amount.

  The predetermined pixel coefficient may be determined when the pixel is positioned in the vicinity of a boundary that forms the specific divided region to which the pixel belongs. Determining the predetermined pixel coefficient based on a smoothing coefficient based on the predetermined fill rate for each of the divided regions.

  Thereby, the image processing apparatus determines the predetermined pixel coefficient based on the smoothing coefficient based on the predetermined fill coefficient for each of the specific divided area and the other divided areas forming the boundary. Thus, it is possible to prevent a problem that the boundary between the divided areas becomes conspicuous due to different correction amounts.

  Further, determining the predetermined pixel coefficient includes determining whether the specific divided region to which the pixel belongs is the divided region having uneven luminance, and determining whether the specific divided region has uneven luminance. When determining that it is not a certain divided area, it is determined whether or not there is the divided area adjacent to the specific divided area, having uneven brightness, and having the predetermined filling rate equal to or higher than a predetermined value, When it is determined that there is no divided area that is adjacent to the specific divided area, has uneven brightness, and the corresponding predetermined fill ratio is equal to or greater than a predetermined value, the predetermined pixel coefficient is determined as the correction data signal. And determining a value such that the data signals are the same signal.

  As a result, the image processing apparatus can perform control so as not to perform correction on a divided region where the divided region with uneven brightness is not adjacent or a divided region where the filled divided region is not adjacent. .

  Still further, determining the predetermined pixel coefficient determines whether or not the predetermined fill rate corresponding to the specific divided area is less than a predetermined value, and corresponds to the specific divided area. If it is determined that the predetermined fill rate is less than a predetermined value, it may further include determining the predetermined pixel coefficient to a value such that the correction data signal and the data signal are the same signal.

  As a result, the image processing apparatus can perform control so as not to perform correction on the divided areas whose fill rate is less than a predetermined value.

  According to the present invention, the image processing apparatus can correct the luminance value of each pixel while considering whether or not the luminance unevenness of the image to be displayed is noticeable.

  More specifically, according to the present invention, the image processing apparatus determines the correction amount of the chromaticity of each color component of each pixel color based on the feature of the image (for example, a filled image), and the determination Based on the correction amount, the luminance value of the pixel can be corrected.

  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.

1 is a diagram illustrating a schematic configuration of an image transmission system according to an embodiment of the present invention. It is a figure for demonstrating the filling rate of the image determined in the image processing apparatus which concerns on one Embodiment of this invention. It is a figure for demonstrating the calculation method of each coefficient in the image processing apparatus which concerns on one Embodiment of this invention. 4 is a flowchart illustrating an operation of the image processing apparatus according to the embodiment of the present invention. It is a figure which shows schematic structure of the image transmission system which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the vicinity of the boundary of the division area of the flame | frame processed in the image processing apparatus which concerns on the 2nd Embodiment of this invention. It is a figure for demonstrating the calculation method of the smoothing coefficient in the image processing apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows operation | movement of the image processing apparatus in the 2nd Embodiment of this invention. It is a figure which shows schematic structure of the image transmission system which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating the relationship between the image of the flame | frame in the image processing apparatus which concerns on the 3rd Embodiment of this invention, and correction amount. It is a flowchart which shows operation | movement of the image processing apparatus which concerns on the 3rd Embodiment of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. In the description of the following drawings, the same or similar parts are denoted by the same or similar reference numerals. The figures are schematic and do not necessarily match actual dimensions and ratios. In some cases, the dimensional relationships and ratios are different between the drawings.

[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of an image transmission system according to an embodiment of the present invention. As shown in the figure, the image transmission system 100 according to the present embodiment includes a transmission device 110 and a reception device 120.

  The transmission device 110 is typically a source device (for example, a personal computer or a set top box) conforming to the eDP (embedded display port) standard, but is not limited to this, and other standards such as DVI (Digital It can be a source device that complies with the Visual Interface standard. The transmission device 110 generates a data signal D including information on luminance and chromaticity of an image to be displayed, information on horizontal synchronization and vertical synchronization, and a pixel clock according to various formats such as a YUV format and an RGB format. The data signal D is transmitted to the receiving device 120. In the following, it is assumed that the data signal D is a signal according to the RGB format.

  The reception device 120 is a sink device (for example, a computer display or a projector) corresponding to the transmission device 110. The reception device 120 generates a correction data signal D ′ based on the data signal D transmitted from the transmission device 110 and displays an image according to the correction data signal D ′. The receiving device 120 includes, for example, an image processing device 130 and a display device 140. The image processing apparatus 130 includes, for example, a position information generation unit 131, a luminance value calculation unit 132, a fill rate calculation unit 133, a coefficient determination unit 134, a reference correction amount determination unit 135, and a correction unit 136. Further, the image processing apparatus 130 may include a buffer (not shown) for adjusting the signal processing timing. For example, the buffer delays the signal to be processed by one frame and outputs the delayed signal. The display device 140 includes a display panel made of, for example, a liquid crystal element or an organic electroluminescence element, and is a component for displaying an image based on an image signal.

  The position information generation unit 131 generates a position signal p (x, y) based on the data signal D transmitted from the transmission device 110. Specifically, the position information generation unit 131 determines the position (horizontal position x and vertical position y) of the pixel to be displayed based on the information about the horizontal synchronization and vertical synchronization included in the data signal D and the pixel clock. The position signal p (x, y) is generated based on the specified position. The position information generation unit 131 outputs the generated position signal p (x, y) to the fill rate calculation unit 133, and also outputs the position signal p (x, y) via a buffer (not shown) to a reference correction amount determination unit. It outputs to 135.

  The luminance value calculation unit 132 calculates the luminance value Br of each pixel based on the data signal D. Specifically, the luminance value calculation unit 132 calculates information regarding luminance as the luminance value Br based on the chromaticity of each color component indicated by the data signal D. When the data signal D is a signal conforming to a format other than the RGB format, the luminance value calculation unit 132 converts the format of the signal to the RGB format, and then, based on the chromaticity of each color component obtained from the conversion result, A luminance value Br is calculated. The luminance value calculation unit 132 outputs the luminance value Br to the paint rate calculation unit 133 and outputs the luminance value Br to the coefficient determination unit 134 via a buffer (not shown). The luminance value Br is typically a value indicating the degree of brightness of the pixel displayed on the display device 140. Alternatively, the luminance value Br may be a value obtained by multiplying the chromaticity of each color component (for example, red component, green component, and blue component) of a certain pixel by a predetermined weight coefficient, for example. As another example, the luminance value calculation unit 132 may be configured to calculate the luminance value Br in units of blocks including, for example, 8 × 8 pixels, instead of calculating the luminance value Br in units of pixels.

  The fill rate calculation unit 133 calculates and determines the fill rate F of the image using, for example, a histogram. The image filling rate F is a ratio of a predetermined image to a predetermined area. For example, the fill rate F of the image is calculated by the ratio of the pixel region having the luminance value Br higher than the predetermined threshold value TH to the entire frame to be displayed. The fill rate calculation unit 133 according to the present embodiment divides one frame including an image to be displayed into a plurality of divided regions, obtains a histogram of the luminance value Br of the image portion in each divided region, and based on each histogram, An image fill rate F for one frame is determined. The fill rate calculation unit 133 includes, for example, a histogram creation unit 1331 and a fill rate determination unit 1332.

  The histogram creation unit 1331 divides an image in one frame to be displayed into several divided areas, and creates a histogram of luminance values Br for each divided area. The histogram of the luminance value Br has n1 pixels at the first luminance level (for example, the luminance value Br is 150 or more and less than 160) and the second luminance level (for example, the luminance value Br is 160 or more and less than 170). The total number of pixels having the corresponding luminance value for each predetermined luminance level, such as n2 pixels, is shown. Each time the luminance value Br calculated by the luminance value calculating unit 132 is updated, the histogram creating unit 1331 counts how many luminance values Br exist for each of the plurality of luminance ranges, thereby obtaining the position signal p. A histogram of the luminance value Br in the divided area to which the pixel position indicated by (x, y) belongs is created.

  The fill rate determining unit 1332 calculates a fill rate F (i) for each divided region corresponding to each divided region based on the histogram of each divided region created by the histogram creating unit 1331 (i is a value for each divided region). A value indicating the associated index.) Furthermore, the fill rate determination unit 1332 determines, for example, a fill rate F as a representative value based on the calculated fill rate F (i) for each divided region corresponding to each divided region. The fill rate determination unit 1332 typically determines the maximum value of the fill rate F (i) for each divided region corresponding to each divided region as the fill rate F, but is not limited thereto. The minimum value, median value, average value, etc. can be determined as the fill rate F.

  The coefficient determination unit 134 displays the frame coefficient f obtained based on the fill rate F determined by the fill rate calculation unit 133 and the delay value output from the luminance value calculation unit 132 by a buffer (not shown). Based on the luminance value Br of the power pixel, a pixel coefficient g for correcting a reference correction amount α determined by a reference correction amount determination unit 135 described later is determined. That is, the frame coefficient f is a coefficient depending on the magnitude of the image fill rate F in the frame, and the pixel coefficient g is a coefficient depending on the magnitude of the luminance value Br of the pixel. The coefficient determination unit 134 includes, for example, a frame coefficient determination unit 1341 and a pixel coefficient determination unit 1342.

  The frame coefficient determination unit 1341 determines the frame coefficient f based on the fill rate F determined by the fill rate calculation unit 133. The frame coefficient determination unit 1341 typically determines the value of the frame coefficient f so that it increases as the fill rate F value increases and decreases as the fill rate F value decreases. A specific method for determining the frame coefficient f will be described later.

  The pixel coefficient determination unit 1342 determines the pixel coefficient g based on the frame coefficient f determined by the frame coefficient determination unit 1341 and the luminance value Br of the pixel to be displayed. The pixel coefficient determination unit 1342 typically determines the value of the pixel coefficient g so that it decreases as the luminance value Br increases and increases as the luminance value Br decreases. A specific method for determining the pixel coefficient g will be described later.

  The reference correction amount determination unit 135 includes, for example, a lookup table. The look-up table is a table that associates the positional information of the pixels of the image to be displayed, the chromaticity of each color component of the pixels of the image to be displayed, and the reference correction amount α corresponding to the positional information. . The reference correction amount determination unit 135 determines the reference correction amount α corresponding to the pixel indicated by the position signal p (x, y) output after being delayed by a buffer (not shown) by referring to the lookup table. The reference correction amount α is a correction amount of the luminance value of the pixel that is measured and evaluated in advance by a known method, for example.

  The correction unit 136 determines the correction amount Δα based on the reference correction amount α and the pixel coefficient g, and corrects the chromaticity of each color component indicated by the data signal D in accordance with the determined correction amount Δα, whereby the data signal The luminance unevenness of the image indicated by D is corrected. The correction unit 136 includes a correction amount determination unit 1361 that determines the correction amount Δα, and a calculation unit 1362 that corrects the chromaticity of each color component indicated by the data signal D by the correction amount Δα.

  The correction amount determination unit 1361 determines the correction amount Δα based on the reference correction amount α and the pixel coefficient g. Specifically, the correction amount determination unit 1361 multiplies the reference correction amount α determined by the reference correction amount determination unit 135 by the pixel coefficient g determined by the coefficient determination unit 134, for example, to thereby obtain the correction amount Δα. calculate.

  The calculation unit 1362 adds, for example, the correction amount Δα determined by the correction amount determination unit 1361 to the chromaticity of each color component indicated by the data signal D output after being delayed by a buffer (not shown). The chromaticity of each color component is corrected. The calculation unit 1362 outputs the correction result to the display device 140 as a correction data signal D ′. When the data signal D is a signal conforming to a format other than the RGB format, the arithmetic unit 1362 converts the format of the signal into the RGB format, and corrects the correction amount Δα with respect to the chromaticity of each color component indicated by the conversion result. Is corrected, and the format of the result of the correction is converted back to the original format and output to the display device 140 as a corrected data signal D ′.

  Note that the image processing apparatus 130 may include, for example, a gamma correction unit that performs gamma correction at the subsequent stage of the correction unit 136. Further, when the display device 140 is a liquid crystal panel, the image processing device 130 may include an overdrive processing unit that performs overdrive processing for increasing the response speed of the liquid crystal element.

  As described above, the display device 140 includes, for example, a liquid crystal element and an organic electroluminescence element. The display device 140 displays an image on a display panel, for example, according to the correction data signal D ′ output from the correction unit 136 of the image processing device 130. In this example, the display device 140 is provided in the reception device 120, but the display device 140 is not limited to this, and may be provided separately from the reception device 120.

  The image processing apparatus 130 configured as described above calculates a luminance value Br for each pixel to be displayed based on the data signal D supplied from the transmission apparatus 110, and based on the calculated luminance value Br. The fill rate F of the image to be displayed is determined. Subsequently, the image processing apparatus 130 subsequently corrects the chromaticity correction amount of each color component of each pixel indicated by the data signal D based on the luminance value Br of the pixel, the fill rate F of the image, and the position information of the pixel. Δα is determined, and the chromaticity of each color component of the pixel is corrected. As described above, the image processing apparatus 130 corrects the chromaticity of each color component of each pixel to be displayed indicated by the data signal D based on the feature of the image (for example, a filled image and / or its state). The luminance value of the pixel can be corrected.

  FIG. 2 is a diagram for explaining the fill ratio of the image determined in the image processing apparatus according to the embodiment of the present invention. Specifically, FIG. 10A shows the relationship between the distribution of the luminance value Br of the image in one frame to be displayed and each divided area obtained by dividing the frame, and FIG. The histogram of the luminance value Br of the pixels in the region, the fill rates F (1) to F (4) for each divided region, and the fill rate F of the entire frame are shown.

  As shown in FIG. 4A, for example, four divided areas 201 to 204 are defined for one frame to be displayed. FIG. 4A shows that the image area 205 in one frame to be displayed covers the divided areas 201 to 204. Here, the image area 205 is an area configured by pixels having a luminance value Br higher than a predetermined threshold value TH, and can be recognized as an image having some kind of outline by the user.

  In the upper part of FIG. 5B, an example of a histogram created by the fill rate calculation unit 133 for each of the divided areas 201 to 204 is shown. The fill rate calculation unit 133 determines the fill rate F (i) for each divided region of the divided regions 201 to 204 based on each created histogram, and further determines the fill rate F for the entire frame. Further, in the lower part of FIG. 5B, the fill rates F (1) to F (4) for each of the divided areas 201 to 204 are 0.7, 0.1, 0.4, and 0, respectively. .2 and the fill rate F of the entire frame is 0.7. The fill rate F is, for example, the maximum value among the fill rates F (i) for each divided region determined for each divided region.

  FIG. 3 is a diagram for explaining a method for calculating each coefficient in the image processing apparatus according to the embodiment of the present invention.

First, the frame coefficient determination unit 1341 determines the frame coefficient f according to <Equation 1> below based on the fill rate F determined by the fill rate calculation unit 133.
f = 0 (where F ≦ Fmin), 2 × (F−Fmin) (where Fmin <F <Fmax), 1 (where Fmax ≦ F) (Formula 1)
Here, Fmin is the minimum reference value of the fill rate F, and Fmax is the maximum reference value of the fill rate F.

  That is, the frame coefficient determination unit 1341 determines the frame coefficient f to be 0 if the fill rate F is equal to or less than the minimum reference value Fmin according to <Expression 1>. On the other hand, the frame coefficient determination unit 1341 determines the frame coefficient f to be 1 if the fill rate F is equal to or greater than the maximum reference value Fmax. Further, the frame coefficient determination unit 1341 determines the frame coefficient f to be a predetermined value corresponding to the fill ratio F within a range larger than 0 and smaller than 1 if the fill ratio F is larger than the minimum reference value Fmin and smaller than the maximum reference value Fmax. Decide on a value. In this example, the frame coefficient determination unit 1341 determines the frame coefficient f so as to perform linear interpolation between 0 and 1. Alternatively, the frame coefficient f may be determined using a polynomial, an exponential function, a trigonometric function, or a combination thereof.

Next, the pixel coefficient determination unit 1342 determines the pixel coefficient g according to the following <Equation 2>, based on the luminance value Br of the pixel and the frame coefficient f determined by the frame coefficient determination unit 1341.
g = 1 (where 0 ≦ Br ≦ Brmin), (1−f) × (Brmax−Brmin) / (Brmax−Brmin) + f (where Brmin <Br ≦ Brmax), f (where Brmax <Br ≦ 255) ) <Formula 2>
Here, Brmin is a minimum reference value for luminance, and Brmax is a maximum reference value for luminance.

  That is, the pixel coefficient determination unit 1342 determines the pixel coefficient g to be 1 when the luminance value Br is equal to or less than the minimum reference value Brmin. On the other hand, the pixel coefficient determination unit 1342 determines the pixel coefficient g as the value of the frame coefficient f if the luminance value Br is greater than the maximum reference value Brmax. In addition, the pixel coefficient determination unit 1342 responds to the luminance value Br within a range in which the value of the pixel coefficient g is greater than the frame coefficient f and smaller than 1 if the luminance value Br is greater than the minimum reference value Brmin and less than or equal to the maximum reference value Brmax. Determined to a predetermined value. In this example, the pixel coefficient determination unit 1342 determines the pixel coefficient g so as to perform linear interpolation between the frame coefficient f and 1. Alternatively, the pixel coefficient g may be determined using a polynomial, an exponential function, a trigonometric function, or a combination thereof.

Next, the correction amount determination unit 1361 performs correction according to the following <Expression 3> based on the reference correction amount α output from the reference correction amount determination unit 135 and the pixel coefficient g output from the pixel coefficient determination unit 1342. The quantity Δα is determined.
Δα = α × g (Formula 3)
Here, g is f-1 and f is 0-1.

Then, the arithmetic unit 1362 generates and outputs a correction data signal D ′ according to the following <Equation 4> based on the data signal D and the correction amount Δα output from the correction amount determination unit 1361.
D ′ = D + Δα (Formula 4)
Here, Δα is 0 to α.

  As described above, the image processing apparatus 130 determines the correction amount Δα based on the image fill rate F and the pixel luminance value Br in the frame to be displayed. Therefore, the correction amount Δα has a large fill rate F. The smaller the fill rate F, the smaller the luminance value Br. The smaller the luminance value Br, the smaller the luminance value Br, and the smaller the luminance value Br. In particular, when the fill rate F is smaller than the minimum reference value Fmin and the luminance value Br is larger than the maximum reference value Brmax, the image processing apparatus 130 does not correct the chromaticity of each color component of the pixel of the data signal D. The correction data signal D ′ is output as it is. Therefore, depending on the characteristics of the image, the luminance unevenness of the pixel may not be noticeable. In this case, the chromaticity of each color component is not corrected (that is, the correction amount Δα = 0), and thus the luminance does not change. Thus, an excessive decrease in the luminance of the image can be suppressed, and a good image can be displayed.

  FIG. 4 is a flowchart showing the operation of the image processing apparatus according to the embodiment of the present invention. With reference to the figure, the image processing apparatus 130 first calculates a luminance value Br for each pixel of an image to be displayed transmitted from the transmission apparatus 110 (S401).

  Next, the image processing apparatus 130 determines a fill rate F based on the calculated luminance value Br of each pixel (S402). Specifically, based on the calculated luminance value Br of each pixel, the image processing apparatus 130 generates a histogram of the luminance value Br for each divided region of the frame including the image to be displayed, and based on the histogram Then, the filling rate F (i) for each divided region in each divided region is determined, and further, the filling rate F of the image for the entire frame is determined based on the filling rate F (i) for each divided region.

  Next, the image processing apparatus 130 determines the frame coefficient f based on the determined fill rate F (S403), and further determines the pixel coefficient g based on the determined frame coefficient f and the luminance value Br of the pixel. (S404). Further, the image processing apparatus 130 determines the correction amount Δα based on the determined pixel coefficient g and the reference correction amount α determined based on the position signal p (x, y) (S405).

  Then, the image processing apparatus 130 corrects the data signal D based on the determined correction amount Δα, and generates and outputs a corrected data signal D ′ (S406).

  As described above, the image processing apparatus 130 determines the fill rate F of the frame based on the brightness value Br of each pixel of the frame to be displayed, and the pixel coefficient based on the fill rate F and the brightness value Br of the pixel. g is determined. Subsequently, the image processing apparatus 130 determines the chromaticity of each color component of the pixel indicated by the data signal D based on the pixel coefficient g and the reference correction amount α according to the chromaticity and position information of each color component of the pixel. The correction amount Δα is determined, and the chromaticity of each color component of the pixel is corrected. In other words, the image processing apparatus 130 determines the correction amount Δα for the chromaticity of each color component of each pixel based on the feature of the image (for example, a filled image). Therefore, depending on the feature of the image, the chromaticity of each color component is determined. Control can be performed so that correction is not performed (correction amount Δα = 0).

[Second Embodiment]
In the first embodiment described above, one fill rate F is calculated for the entire frame to be displayed, and the correction amount for the chromaticity of each color component of the pixel in the entire frame is calculated according to the calculated fill rate F. However, the present embodiment divides the entire frame to be displayed into a plurality of divided regions, calculates the fill rate F for each of the divided regions, and calculates the calculated fill rate. According to F, the correction amount for the chromaticity of each color component of the pixel is determined in each divided region. For example, as described in the first embodiment, the filling rate Fd for each of the divided regions may be determined based on the filling rate Fd (i) for each divided region obtained by further dividing the divided region.

FIG. 5 is a diagram showing a schematic configuration of an image transmission system according to the second embodiment of the present invention.
As shown in the figure, the receiving device 120 ′ of the present embodiment includes a fill rate calculation unit 133 ′ that calculates the fill rates F1 to Fn for each divided region of the frame, and a frame coefficient according to the plurality of fill rates F1 to Fn. and a coefficient determination unit 134 ′ that determines the pixel coefficient g with respect to the reference correction amount α after smoothing f1 to fn. In the figure, the same components as those in the first embodiment are denoted by the same reference numerals, and therefore the description thereof is omitted as appropriate.

  As described above, the position information generation unit 131 generates the position signal p (x, y) based on the data signal D transmitted from the transmission device 110, and in the present embodiment, the generated position signal p (x , Y) is output to the fill rate calculation unit 133 ′ and is also output to the coefficient determination unit 134 ′. The position signal p (x, y) for the coefficient determination unit 134 ′ is delayed by a buffer (not shown) so as to be synchronized with the processing timing of the paint rate calculation unit 133 ′, and is input to the coefficient determination unit 134 ′. obtain.

  The fill rate calculation unit 133 ′ includes a plurality of histogram creation units 1331 (1) ′ to 1331 (n) ′ and a plurality of fill rate determination units 1332 (1) to 1332 provided so as to correspond to the plurality of divided regions, respectively. 1332 (n) is included. Therefore, the fill rate calculation unit 133 ′ includes a divided region specifying unit 1333 that specifies which divided region the pixel indicated by the position signal p (x, y) belongs to.

  Specifically, the divided area specifying unit 1333 has, for example, a table that defines the range of divided areas in the frame, and the position signal p (x, y received from the position information generating unit 131 with reference to the table. ) To specify the divided region to which the pixel indicated by the position signal p (x, y) belongs, and output the position signal p (x, y) to the histogram creation unit 1331 ′ corresponding to the specified divided region. To do.

  Upon receiving the position signal p (x, y), each of the plurality of histogram creation units 1331 ′ creates a histogram of luminance values for each area obtained by further dividing the divided area (hereinafter referred to as “fine divided area”). . That is, the histogram creation unit 1331 ′ according to the present embodiment creates a histogram of the luminance value Br for each subdivided area of the divided area, instead of creating a histogram of the brightness value Br for each divided area obtained by dividing the frame. Each of the plurality of histogram creation units 1331 ′ outputs the created histogram of the brightness value Br to the corresponding fill rate determination unit 1332.

  Each of the plurality of fill rate determination units 1332 determines the fill rate F (i) of the corresponding subdivision area based on the histogram of the luminance values for each subdivision area in the corresponding subarea.

  The coefficient determination unit 134 'includes, for example, a plurality of frame coefficient determination units 1341 (1) to 1341 (n) and a pixel coefficient determination unit 1342. Further, in the present embodiment, the coefficient determination unit 134 ′ includes a smoothing coefficient determination unit 1343 and a boundary definition unit 1344 in order to consider the fill rate F in the vicinity of the boundary between adjacent divided regions.

  The plurality of frame coefficient determination units 1341 are provided so as to correspond to the respective histogram creation units 1331 (1) ′ to 1331 (n) ′ of the fill rate calculation unit 133 ′ (that is, to correspond to each divided region). ing. As described above, each of the plurality of frame coefficient determination units 1341 (1) to 1341 (n) determines the frame coefficients f1 to fn based on the fill rates F1 to Fn of the corresponding divided regions.

  The smoothing coefficient determination unit 1343 determines a smoothing coefficient j according to whether or not the pixel to be displayed is located in the vicinity of the boundary of the divided area. Specifically, the smoothing coefficient determination unit 1343 specifies which divided region the pixel indicated by the input position signal p (x, y) belongs to, for example, the boundary definition unit 1344. Then, it is determined whether or not it is located within a predetermined distance range from the boundary of the specified divided region, that is, whether or not it is located in the vicinity of the boundary. When the smoothing coefficient determining unit 1343 determines that the pixel is not located in the vicinity of the boundary, the smoothing coefficient is determined by using the value of the frame coefficient f output by the frame coefficient determining unit 1341 corresponding to the divided region to which the pixel belongs. Determine as j. On the other hand, when the smoothing coefficient determination unit 1343 determines that the pixel is located in the vicinity of the boundary, the smoothing coefficient determination unit 1343 sets each frame coefficient f output by each frame coefficient determination unit 1341 corresponding to each divided region forming the boundary. Based on this, the smoothing coefficient j is determined. Details of the method for determining the smoothing coefficient j will be described later.

  The boundary definition unit 1344 is a table that defines, for example, a range of divided areas in a frame and a range in the vicinity of the boundary of each divided area.

  The pixel coefficient determination unit 1342 determines the pixel coefficient g based on the luminance value Br of the pixel and the smoothing coefficient j determined by the smoothing coefficient determination unit 1343. The method for determining the pixel coefficient g is the same as described above except that the smoothing coefficient j is used instead of the frame coefficient f, and the description thereof will be omitted.

  The image processing apparatus 130 ′ configured as described above determines the fill rate F for each divided region of the frame based on the luminance value Br of each pixel of the image to be displayed, and the pixel is positioned in the vicinity of the boundary. The smoothing coefficient j determined according to the above is determined, and the pixel coefficient g is determined based on the luminance value Br of the pixel and the smoothing coefficient j. Subsequently, the image processing device 130 ′ determines the chromaticity of each color component of the pixel indicated by the data signal D based on the pixel coefficient g and the chromaticity of each color component of the pixel and the reference correction amount α according to the position information. A correction amount Δα for the pixel is determined, and the luminance value of the pixel is corrected by correcting the chromaticity of each color component of the pixel. That is, when the pixel to be displayed is not located in the vicinity of the boundary of the divided region, the image processing apparatus 130 ′ determines the frame coefficient f of the divided region to which the pixel belongs as the smoothing coefficient j, while being displayed. When the pixel is located in the vicinity of the boundary of the divided area, the smoothing coefficient j is determined based on each frame coefficient f of each divided area forming the boundary.

  Therefore, the image processing apparatus 130 ′ determines the correction amount Δα for the chromaticity of each color component of each pixel based on the image characteristics for each divided region obtained by dividing the frame. Therefore, depending on the image characteristics, the color of each color component In addition to controlling the degree of correction (correction amount Δα = 0) and correcting the chromaticity of each color component with higher accuracy, the luminance can be corrected with higher accuracy. In addition, since the image processing apparatus 130 ′ uses the smoothing coefficient j, it is possible to prevent a problem that the boundary between the divided areas becomes conspicuous when the correction amount Δα is different between the adjacent divided areas.

  FIG. 6 is a view for explaining the vicinity of the boundary of the divided area of the frame processed in the image processing apparatus according to the second embodiment of the present invention. Specifically, FIG. 5A shows a region of interest including the boundary of the divided region of the frame, and FIG. 5B shows an enlarged view of the region of interest.

  As shown in FIG. 5A, the frame 600 is divided into four divided areas 601 to 604, and each of the divided areas 601 to 604 is divided into a plurality of subdivided areas 201, 202,. In addition, the boundaries between adjacent divided regions are indicated as boundaries b12, b13, b24, and b34, respectively. The code b1234 is referred to as a boundary between the divided areas 601 to 604. In this example, it is assumed that frame coefficients f1 to f4 are determined for each of the divided regions 601 to 604.

  Consider the pixels Q1 and Q2 in the frame with reference to FIG. 5B which shows an enlarged view of the region of interest 605 in FIG. In the present example, the vicinity of the boundary means that the pixel to be displayed is within the distance r from the boundaries b12, b13, b24, and b34 of the divided regions 601 to 604. In the drawing, a broken line is drawn at a distance r from the boundary between the divided regions 601 to 604.

  As shown in FIG. 5B, the pixel Q1 in the divided area 601 is located at a distance y (y <r) in the vertical direction from the boundary b13 with the divided area 603. Therefore, the divided area 601 And 603 are pixels located in the vicinity of the boundary b13. Further, the pixel Q2 in the divided area 601 is located at a distance x (x <y) in the horizontal direction from the boundary with the divided area 602 and at a distance y from the boundary with the divided area 603. Therefore, the pixel Q2 is a pixel located in the vicinity of the boundary b12 and in the vicinity of the boundary b13. In this case, since the pixel Q2 is located away from the boundary b 1234 by the distance x in the horizontal direction and the distance y in the vertical direction, the pixel Q2 is regarded as being near the boundary with the divided region 604.

  FIG. 7 is a diagram for explaining a smoothing coefficient calculation method in the image processing apparatus according to the embodiment of the present invention.

  First, each of the frame coefficient determination units 1341 (1) to 1341 (n) is described based on the fill rates F1 to Fn output from the corresponding fill rate determination units 1332 (1) to 1332 (n) < Corresponding frame coefficients f1 to fn are determined according to Equation 1>.

  As described above, the smoothing coefficient determination unit 1343 determines the smoothing coefficient j according to whether or not the pixel to be displayed is located in the vicinity of the boundary of the divided region. That is, when the smoothing coefficient determining unit 1343 determines that the pixel indicated by the input position signal p (x, y) is not located near the boundary, the frame coefficient determining unit corresponding to the divided region to which the pixel belongs. The value of the frame coefficient f output from 1341 is determined as the smoothing coefficient j. On the other hand, when the smoothing coefficient determining unit 1343 determines that the pixel is located in the vicinity of the boundary of any divided region, each frame coefficient determining unit 1341 corresponding to each divided region forming the boundary outputs A smoothing coefficient j is determined based on each frame coefficient f. For example, in the case of the pixel Q2 as shown in FIG. 4B, the smoothing coefficient j is determined based on the frame coefficients f1 to f4 output from the frame coefficient determination unit 1341 corresponding to each of the divided regions 601 to 604. The

More specifically, the smoothing coefficient determination unit 1343 determines that the pixel to be displayed is within a predetermined distance in either the vertical direction or the horizontal direction from the boundary of each divided region (FIG. 6 ( In the case of Q1 in b), the smoothing coefficient j is determined according to the following <Equation 5>.
j = (f1−f3) × y / (2 × r) + (f1 + f3) / 2 (Formula 5)

On the other hand, when the smoothing coefficient determination unit 1343 determines that the pixel is within a predetermined distance in both the vertical direction and the horizontal direction from the boundary of each divided region (in the case of Q2 in FIG. 6B), The smoothing coefficient j is determined according to the following <Equation 6>.
j = (2 × r−y) × (2 × r−x) × f1 + (r + x) × (r−y) × f2 + (r−x) × (r + y) × f3 + (r−x) × (r− y) × f4 (Formula 6)

  The smoothing coefficient j may be determined by linearly interpolating the values of the frame coefficients f1 to f4. Alternatively, it may be determined by a polynomial, an exponential function, a trigonometric function, or a combination thereof.

  Next, the pixel coefficient determination unit 1342 determines the pixel coefficient g according to the above-described <Expression 2> based on the pixel luminance value Br and the smoothing coefficient j determined by the smoothing coefficient determination unit 1343. However, with respect to <Expression 2>, in this embodiment, the smoothing coefficient j is used instead of the frame coefficient f. The image coefficient determination unit 1342 outputs the determined image coefficient g to the correction amount determination unit 1361 described above.

  FIG. 8 is a flowchart showing the operation of the image processing apparatus according to the second embodiment of the present invention.

  With reference to the figure, the image processing apparatus 130 ′ first calculates a luminance value Br for each pixel of the image to be displayed transmitted from the transmission apparatus 110 (S 801).

  Next, the image processing apparatus 130 'determines the fill rates F1 to Fn for each divided region based on the luminance value Br of each pixel calculated in the process of step S801 (S802). The image processing apparatus 130 'determines frame coefficients f1 to fn for each divided area based on the corresponding fill rates F1 to Fn (S803).

  Subsequently, the image processing apparatus 130 ′ determines whether or not the pixel to be displayed is located in the vicinity of the boundary of the divided area (S 804). When determining that the pixel is located in the vicinity of the boundary of the divided region (Yes in S804), the image processing apparatus 130 ′ determines the smoothing coefficient j based on the frame coefficient f of the divided region that forms the boundary (S804). S805). On the other hand, when the image processing apparatus 130 ′ determines that the pixel is not located near the boundary (No in S804), the frame coefficient f of the divided region to which the pixel belongs is determined as the smoothing coefficient j (S806). ).

  After determining the smoothing coefficient j, the image processing apparatus 130 ′ next determines the pixel coefficient g based on the smoothing coefficient j and the pixel luminance value Br (S807), and further determines the determined pixel coefficient g. Then, the correction amount Δα is determined based on the reference correction amount α determined based on the position signal p (x, y) (S808).

  Then, the image processing apparatus 130 ′ generates a correction data signal D ′ by correcting the data signal D based on the determined correction amount Δα (S 809).

  As described above, the image processing apparatus 130 ′ determines the correction amount Δα for the chromaticity of each color component of each pixel based on the image characteristics for each divided region obtained by further dividing the frame. The control can be performed so that the chromaticity of each color component is not corrected (correction amount Δα = 0), and the chromaticity of each color component is corrected with higher accuracy, so that the luminance is corrected with higher accuracy. be able to. In addition, since the image processing apparatus 130 ′ uses the smoothing coefficient j, it is possible to prevent a problem that the boundary between the divided areas becomes conspicuous when the correction amount Δα is different between the adjacent divided areas.

[Third Embodiment]
The present embodiment is characterized in that the pixel coefficient g is determined based on whether or not each divided region of the frame is a region having luminance unevenness. In addition, the present embodiment is characterized in that the pixel coefficient g is determined based on the divided area to which the displayed pixel belongs and the fill coefficient F of the divided area adjacent thereto.

  FIG. 9 is a diagram showing a schematic configuration of an image transmission system according to the third embodiment of the present invention. As shown in the figure, the receiving device 120 ″ of the present embodiment has a luminance unevenness information storage unit that stores information (hereinafter “brightness unevenness information”) regarding whether or not each divided region is a region having uneven luminance. 137. In the figure, the same components as those in the above embodiment are denoted by the same reference numerals, and therefore the description thereof is omitted as appropriate.

  The luminance unevenness information storage unit 137 is a table that stores, for example, luminance unevenness information UE created based on the luminance unevenness of the display panel (frame) measured and evaluated in advance. The luminance unevenness information storage unit 137 is referred to by the pixel coefficient determination unit 1342 ″ as described later.

  The coefficient determination unit 134 ″ includes, for example, n frame coefficient determination units 1341 (1) to 1341 (n), a pixel coefficient determination unit 1342 ″, a smoothing coefficient determination unit 1343, and a boundary definition unit 1344. Consists of including.

  The pixel coefficient determination unit 1342 ″ further determines the pixel coefficient g using the luminance unevenness information UE of the divided region related to the pixel to be displayed. Specifically, the pixel coefficient determining unit 1342 ″ first refers to the boundary defining unit 1344 according to the input position signal p (x, y), and identifies the divided region to which the pixel to be displayed belongs. Next, the pixel coefficient determination unit 1342 ″ determines whether or not the filling rate F corresponding to the specified divided area is equal to or greater than the minimum reference value Fmin. When the pixel coefficient determination unit 1342 ″ determines that the filling rate F corresponding to the specified divided area is less than the minimum reference value Fmin, the value of the pixel coefficient g is the same as the data signal D and the correction data signal D ′. The value is determined to be a signal (for example, 0). On the other hand, when the pixel coefficient determination unit 1342 ″ determines that the fill rate F corresponding to the specified divided region is equal to or greater than the minimum reference value Fmin, the pixel coefficient determination unit 1342 ″ refers to the luminance unevenness information storage unit 137 and It is determined whether or not the specified divided region to which the pixel belongs is a region having uneven luminance. Then, the pixel coefficient determination unit 1342 ″ determines the pixel coefficient g as described below according to whether or not the specified divided area is an area having luminance unevenness.

  That is, when the pixel coefficient determination unit 1342 ″ determines that the specified divided region has uneven luminance, the pixel coefficient is determined based on the smoothing coefficient j output from the smoothing coefficient determination unit 1343 and the luminance value Br of the pixel. The coefficient g is determined.

  On the other hand, when the pixel coefficient determination unit 1342 '' determines that the specified divided region does not have luminance unevenness, the divided region adjacent to the specified divided region further has luminance unevenness, In addition, it is determined whether or not the filling rate F corresponding to the adjacent divided region is equal to or greater than the minimum reference value Fmin. When the pixel coefficient determining unit 1342 ″ determines that the adjacent divided area has uneven luminance and the fill rate F corresponding to the adjacent divided area is equal to or greater than the minimum reference value Fmin, the smoothing coefficient j And the value of the pixel coefficient g based on the luminance value Br, while the adjacent divided area has no luminance unevenness, or the fill rate F corresponding to the adjacent divided area is less than the minimum reference value Fmin When it is determined that there is, the value of the pixel coefficient g is determined to a value (for example, 0) such that the data signal D and the corrected data signal D ′ are the same signal.

  The image processing apparatus 130 '' configured as described above determines whether or not the divided area to which the pixel to be displayed belongs is filled, and at least one of the divided areas adjacent to the divided area to which the pixel belongs has uneven luminance. Whether or not to correct the image is determined based on whether or not the divided area adjacent to the divided area to which the pixel belongs is filled. Thereby, the image processing device 130 ″ determines whether or not to correct the image based on the feature of the image (for example, whether the image is a filled image) and the luminance unevenness characteristic of the display device 140. be able to. Therefore, the image processing apparatus 130 ″ corrects, for example, a non-filled divided region, a divided region where a nonuniform luminance divided region is not adjacent, or a divided region where a filled divided region is not adjacent. It can be controlled so that there is no.

  FIG. 10 is a diagram for explaining the relationship between the image of the frame and the correction amount in the image processing apparatus according to the third embodiment of the present invention. It is a figure for demonstrating the relationship between the presence or absence of the filling of the input image in a flame | frame, the presence or absence of the brightness unevenness of a division area, and a correction amount.

  FIG. 6A shows that the frame is composed of divided areas 1001 and 1002, and the divided area 1001 has luminance unevenness surrounded by a broken line 1003. In this example, for the sake of simplicity of explanation, the number of frame division regions is two. The uneven brightness information storage unit 137 described above stores that the divided area 1001 is an area having uneven brightness and the divided area 1002 is an area having no uneven brightness.

  FIG. 4B shows the relationship between the fill state of the divided area to which the pixel to be displayed belongs and the correction amount. In this example, if the value of the filling rate F corresponding to the divided area is less than the minimum reference value Fmin, the filling state of the divided area is not filled, and the value of the filling rate F is equal to or greater than the minimum reference value Fmin. If it is, it is said that it is filled.

[When a pixel to be displayed belongs to the divided area 1001]
Referring to FIG. 7B, when the image processing apparatus 130 ″ determines that the pixel to be displayed belongs to the divided area 1001 (that is, the divided area having uneven luminance), the divided area 1002 is filled. Whether or not correction is required for the pixel is determined regardless of whether or not the pixel is present. The image processing apparatus 130 ″ determines the value of the pixel coefficient g based on the smoothing coefficient j, the luminance value Br, and the fill rate F of the divided area 1001, and is determined based on the pixel coefficient g and the reference correction amount α. The luminance of the pixel is corrected by correcting the chromaticity of each color component of the pixel based on the correction amount Δα to be corrected. In this case, if the divided area 1001 is filled, the correction amount Δα depends on the fill rates F1 to F2 of the divided areas 1001 and 1002 and the luminance value Br of the pixel, while the divided area 1001 is filled. Otherwise, the value is such that the data signal D and the correction data signal D ′ are the same signal (for example, 0).

[When the pixel to be displayed belongs to the divided area 1002]
When the image processing apparatus 130 ″ determines that the pixel to be displayed belongs to the divided area 1002 (that is, the divided area having no luminance unevenness), is the divided area 1001 adjacent to the divided area 1002 filled? Based on whether or not, the necessity of correction for the pixel is determined. When the image processing apparatus 130 ″ determines that the image of the divided region 1001 is not filled, it determines the pixel coefficient g to be 0. On the other hand, when the image processing apparatus 130 ″ determines that the divided area 1001 is filled, the pixel coefficient g is based on the smoothing coefficient j, the luminance value Br, and the filling ratio F of the divided area 1002. And the luminance of the pixel is corrected by correcting the chromaticity of each color component of the pixel based on the correction amount Δα determined based on the pixel coefficient g and the reference correction amount α. In this case, if the divided area 1002 is filled, the correction amount Δα depends on the filling rates F1 to F2 of the divided areas 1001 and 1002 and the luminance value Br of the pixel, while the divided area 1002 is not filled. For example, the data signal D and the correction data signal D ′ have values (for example, 0) such that they are the same signal.

  FIG. 11 is a flowchart showing the operation of the image processing apparatus according to the third embodiment of the present invention. The image processing apparatus 130 ″ determines the fill rates F1 to Fn for each divided region (S1101).

  The image processing apparatus 130 ″ determines frame coefficients f1 to fn for each divided area based on the fill rates F1 to Fn corresponding to each divided area (S1102). The image processing apparatus 130 ″ determines whether or not the divided area to which the pixel to be displayed belongs is filled (S1103). When the image processing device 130 ″ determines that the divided region to which the pixel belongs is not filled (No in S <b> 1103), the process proceeds to step S <b> 1106. On the other hand, when the image processing device 130 ″ determines that the divided region to which the pixel belongs is filled (Yes in S1103), the image processing device 130 ″ determines that the division to which the pixel to be displayed belongs. It is determined whether the area has uneven brightness (S1104). When the image processing device 130 ″ determines that the divided region to which the pixel to be displayed belongs has uneven luminance (No in S 1104), the process proceeds to step S 1107. On the other hand, when the image processing apparatus 130 ″ determines that the divided region to which the pixel to be displayed belongs does not have luminance unevenness (Yes in S1104), the image processing device 130 ″ is painted and has luminance unevenness. It is determined whether the divided area is adjacent to any of the divided areas to which the pixel belongs (S1105). When the image processing device 130 ″ determines that the divided region having unevenness in brightness is not adjacent to any of the divided regions to which the pixel belongs (Yes in S1105), the pixel coefficient g is used as data. A value (for example, 0) is determined such that the signal D and the correction data signal D ′ are the same signal (S1106), and the process proceeds to step S1109. On the other hand, when the image processing apparatus 130 ″ determines that at least one or more divided areas that are filled and have uneven luminance are adjacent to the divided area to which the pixel belongs (No in S1105). The process proceeds to step S1107.

  The image processing apparatus 130 ″ determines the smoothing coefficient j based on the position of the pixel to be displayed in the frame and the frame coefficients f1 to fn (S1107). The image processing apparatus 130 ″ determines the pixel coefficient g based on the determined smoothing coefficient j and the luminance value Br of the pixel (S 1108), and proceeds to the process of step S 1109.

  The image processing apparatus 130 ″ determines the correction amount Δα based on the determined pixel coefficient g and the reference correction amount α determined based on the data signal D and the position signal p (x, y) (S1109). . The image processing apparatus 130 ″ corrects the data signal D based on the determined correction amount Δα, and generates a corrected data signal D ′ (S1110).

  As described above, the image processing apparatus 130 ″ determines whether or not the divided region to which the pixel to be displayed belongs is filled, and at least one of the divided regions adjacent to the divided region to which the pixel belongs has uneven luminance. And whether or not to correct the image is determined depending on whether or not the divided area adjacent to the divided area to which the pixel belongs is filled. Thereby, the image processing device 130 ″ determines whether or not to correct the image based on the feature of the image (for example, whether the image is a filled image) and the luminance unevenness characteristic of the display device 140. be able to. Therefore, the image processing apparatus 130 ″ corrects, for example, a filled divided area, a divided area where luminance unevenness is not adjacent, or a divided area where the filled divided area is not adjacent. It can be controlled so that there is no.

  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 above embodiment, the luminance of the pixel of the image to be displayed is corrected. However, the present invention may be configured to correct the hue. Further, the present invention may be configured to correct the luminance and hue not only for one gradation but also for each different gradation (for example, the light output is 30%, 70%, and 100%).

  In the method disclosed in this specification, steps, operations, or functions may be performed in parallel or in a different order as long as the results do not contradict each other. 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.

  Furthermore, the following forms are also included in the gist of the present invention.

(Appendix 1)
An image processing apparatus that processes a data signal related to an image transmitted from a transmission apparatus and outputs the data signal to a display apparatus, and calculates a luminance value of each pixel indicated by the data signal based on the data signal A luminance value calculation unit that performs position information generation unit that generates position information of each pixel indicated by the data signal in a predetermined frame in the display device based on the data signal, and a plurality of divided regions in the predetermined frame For each of the above, based on the position information and the luminance value, a filling rate calculation unit that calculates a predetermined filling rate, based on at least one of the plurality of the predetermined filling rates and the luminance value of the pixel A coefficient determination unit for determining a predetermined pixel coefficient of the pixel; A correction amount determining unit that determines a correction amount based on the reference correction amount based on the position information and the predetermined pixel coefficient; and correcting the chromaticity of each color component of the pixel indicated by the data signal according to the correction amount. And an arithmetic unit that generates and outputs a correction data signal.

(Appendix 2)
The fill rate calculation unit determines a fill rate for each subdivision area based on a histogram for each subdivision area based on a luminance value of a pixel group in each subdivision area obtained by dividing each subdivision area, and The image processing apparatus according to appendix 1, wherein the predetermined fill rate for each of the divided regions is determined based on the determined fill rate for each of the subdivided regions.

(Appendix 3)
The image processing apparatus according to appendix 1, wherein the coefficient determination unit determines the predetermined pixel coefficient based on the predetermined fill rate for a specific divided region to which the pixel of the divided regions belongs.

(Appendix 4)
A receiving device that processes a data signal related to an image transmitted from a transmitting device and outputs an image according to the data signal, and calculates a luminance value of each pixel indicated by the data signal based on the data signal Each of a value calculation unit, a position information generation unit that generates position information of each pixel indicated by the data signal in a predetermined frame in the display device based on the data signal, and a plurality of divided regions in the predetermined frame In contrast, based on the position information and the brightness value, a fill rate calculation unit that calculates a predetermined fill rate, based on at least one of the plurality of predetermined fill rates and the brightness value of the pixel, A coefficient determination unit for determining a predetermined pixel coefficient of the pixel, and the chromaticity of each color component indicated by the data signal and A correction amount determination unit that determines a correction amount based on a reference correction amount based on position information and the predetermined pixel coefficient; and correcting the chromaticity of each color component of the pixel indicated by the data signal according to the correction amount. A receiving device comprising: an arithmetic unit that generates and outputs a correction data signal; and the display device that displays an image to be displayed indicated by the correction data signal.

  The present invention can be widely used in the field of image transmission systems for transmitting images.

DESCRIPTION OF SYMBOLS 100 ... Image transmission system 110 ... Transmission apparatus 120 ... Reception apparatus 130 ... Image processing apparatus 131 ... Position information generation part 132 ... Luminance value calculation part 133 ... Fill ratio calculation part 1331 ... Histogram creation part 1332 ... Fill ratio determination part 1333 ... Division Area specifying unit 134 ... coefficient determining unit 1341 ... frame coefficient determining unit 1342 ... pixel coefficient determining unit 1343 ... smoothing coefficient determining unit 1344 ... boundary defining unit 135 ... reference correction amount determining unit 136 ... correcting unit 1361 ... correction amount determining unit 1362 ... Calculation unit 137 ... Luminance unevenness information storage unit 140 ... Display devices 201, 202, 203, 204 ... Division area 205 ... Image area 601, 602, 603, 604 ... Division area 605 ... Attention area 1001, 1002 ... Division area 1003 ... Broken line

Claims (14)

An image processing device that processes a data signal related to an image transmitted from a transmission device and outputs the data signal to a display device,
A luminance value calculation unit that calculates the luminance value of each pixel indicated by the data signal based on the data signal;
Based on the data signal, a position information generation unit that generates position information in a predetermined frame in the display device of each pixel indicated by the data signal;
A fill rate calculation unit that calculates a predetermined fill rate based on the position information and the luminance value for each of a plurality of divided regions in the predetermined frame;
A coefficient determination unit that determines a predetermined pixel coefficient of the pixel based on at least one of the plurality of predetermined fill rates and the luminance value of the pixel;
A correction amount determination unit that determines a correction amount based on a chromaticity of each color component of the pixel indicated by the data signal and a reference correction amount based on the position information, and the predetermined pixel coefficient;
A calculation unit that generates and outputs a correction data signal by correcting the chromaticity of each color component of the pixel indicated by the data signal according to the correction amount; and
An image processing apparatus comprising:   The fill rate calculation unit calculates a histogram for each divided region based on a luminance value of the pixel group in each divided region, and based on the calculated histogram, out of the pixel groups in each divided region The image processing apparatus according to claim 1, wherein a ratio of pixels indicating the luminance value equal to or greater than a predetermined threshold value is determined, and the ratio is determined as the predetermined fill rate for each of the divided regions.   The fill rate calculation unit determines a fill rate for each subdivision region based on a histogram for each subdivision region based on a luminance value of a pixel group in each subdivision region obtained by dividing each subregion. The image processing apparatus according to claim 2, wherein a maximum value among the determined fill ratios for each subdivided area is determined as the predetermined fill ratio of the corresponding divided area.   The coefficient determination unit determines a frame coefficient for each of the divided areas according to a size of a predetermined fill rate for each of the divided areas, and determines the predetermined pixel coefficient according to the size of the frame coefficient and the luminance value of the pixel. The image processing apparatus according to claim 1, wherein: The coefficient determination unit includes a boundary definition unit that defines a range of each divided region in the frame and a range in the vicinity of a boundary forming each divided region,
The coefficient determining unit determines a smoothing coefficient determined based on the predetermined fill coefficient for the specific divided region when the pixel is not located in the vicinity of a boundary forming the specific divided region to which the pixel belongs. The image processing apparatus according to claim 1, wherein the predetermined pixel coefficient is determined based on.   When the pixel is located in the vicinity of the boundary that forms the specific divided region, the coefficient determination unit sets the predetermined fill coefficient for each of the specific divided region and the other divided regions that form the boundary. The image processing apparatus according to claim 5, wherein the predetermined pixel coefficient is determined based on a smoothing coefficient based thereon. A brightness unevenness information storage unit for storing information on the presence or absence of brightness unevenness in each of the divided regions;
The coefficient determination unit determines the predetermined pixel coefficient based on information on the presence or absence of luminance unevenness stored in the luminance unevenness information storage unit.
The image processing apparatus according to claim 5.   The coefficient determination unit determines the predetermined pixel coefficient to be the same signal as the correction data signal and the data signal when a filling rate corresponding to a specific divided region to which the pixel belongs is less than a predetermined value. The image processing apparatus according to claim 7, which is determined as follows.   The coefficient determination unit is a divided region where the specific pixel to which the pixel belongs is a non-uniform luminance region, is adjacent to the specific divided region, has a non-uniform luminance, and a corresponding filling rate is equal to or greater than a predetermined value. The image processing apparatus according to claim 8, wherein when there is no certain divided region, the predetermined pixel coefficient is determined to be a value such that the correction data signal and the data signal are the same signal. An image processing method for processing a data signal related to an image transmitted from a transmission device,
Calculating a luminance value of each pixel indicated by the data signal based on the data signal;
Calculating a predetermined fill rate based on the luminance value for each of a plurality of divided regions in a predetermined frame in the display device;
Determining a predetermined pixel coefficient of the pixel based on at least one of a plurality of the predetermined fill rates and a luminance value of the pixel;
Determining a correction amount based on a reference correction amount based on the data signal and the predetermined pixel coefficient;
Generating a correction data signal by correcting the chromaticity of each color component of the pixel indicated by the data signal according to the correction amount, and outputting the correction data signal to the display device;
Including an image processing method.   The predetermined pixel coefficient is determined based on the predetermined fill rate for the specific divided area when the pixel is not located in the vicinity of a boundary forming the specific divided area to which the pixel belongs. The image processing method according to claim 10, further comprising: determining the predetermined pixel coefficient based on a smoothing coefficient to be processed.   The predetermined pixel coefficient is determined when the pixel is located in the vicinity of a boundary forming the specific divided region to which the pixel belongs, and the specific divided region and the other division that determines the boundary. The image processing method according to claim 10, further comprising: determining the predetermined pixel coefficient based on a smoothing coefficient based on the predetermined fill rate for each of the regions. Determining the predetermined pixel coefficient includes
Determining whether the particular segmented region to which the pixel belongs is the segmented region with uneven brightness;
When it is determined that the specific divided area is not the divided area having uneven brightness, the divided area is adjacent to the specific divided area, has uneven brightness, and the predetermined filling rate is equal to or greater than a predetermined value. If it is determined whether there is no divided area that is adjacent to the specific divided area, has uneven brightness, and the corresponding predetermined fill rate is equal to or greater than a predetermined value, Determining a predetermined pixel coefficient to a value such that the correction data signal and the data signal are the same signal,
The image processing method according to claim 10.   Determining the predetermined pixel coefficient determines whether or not the predetermined filling rate corresponding to the specific divided area is less than a predetermined value, and the predetermined pixel coefficient corresponding to the specific divided area is determined. 14. The method according to claim 13, further comprising: determining that the predetermined pixel coefficient is a value such that the correction data signal and the data signal are the same signal when it is determined that the fill rate of the pixel is less than a predetermined value. Image processing method.