WO2011135855A1 - Image conversion device and image conversion method - Google Patents

Image conversion device and image conversion method Download PDF

Info

Publication number
WO2011135855A1
WO2011135855A1 PCT/JP2011/002469 JP2011002469W WO2011135855A1 WO 2011135855 A1 WO2011135855 A1 WO 2011135855A1 JP 2011002469 W JP2011002469 W JP 2011002469W WO 2011135855 A1 WO2011135855 A1 WO 2011135855A1
Authority
WO
WIPO (PCT)
Prior art keywords
conversion
image signal
white balance
image
unit
Prior art date
Application number
PCT/JP2011/002469
Other languages
French (fr)
Japanese (ja)
Inventor
宏吏 沖
健司 土橋
明広 桑原
Original Assignee
パナソニック株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by パナソニック株式会社 filed Critical パナソニック株式会社
Publication of WO2011135855A1 publication Critical patent/WO2011135855A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/80—Camera processing pipelines; Components thereof
    • H04N23/84—Camera processing pipelines; Components thereof for processing colour signals
    • H04N23/88—Camera processing pipelines; Components thereof for processing colour signals for colour balance, e.g. white-balance circuits or colour temperature control

Definitions

  • the present invention relates to an image conversion apparatus that converts an input image signal into an output image signal, and more particularly to an image conversion apparatus that performs white balance adjustment processing and color gamut conversion processing on an image signal.
  • G green
  • R red
  • B blue
  • FIG. 7 is a flowchart showing the flow of white balance adjustment processing and color gamut conversion processing in a conventional image conversion apparatus.
  • step S1002 First, with the signal level of the G signal fixed, the signal level of the R signal and the B signal are adjusted and the signal level of the black level is adjusted (step S1001). Thereafter, a color gamut conversion process is performed (step S1002).
  • ⁇ , ⁇ , and ⁇ are white balance coefficients.
  • (r, g, b) indicates the signal levels of RGB in the image signal before white balance processing.
  • (r in , g in , b in ) indicates the respective RGB signal levels in the image signal after white balance processing.
  • Color gamut conversion processing is expressed by (Expression 2) and (Expression 3).
  • RGB out , g out , b out indicates the RGB signal level in the image signal after the color gamut conversion processing.
  • R in , g in , b in indicate signal levels of RGB in the image signal after white balance adjustment processing (image signal before color gamut conversion processing).
  • the basic conversion matrix is a matrix for adjusting the image signal so that an image having a target chromaticity point color is displayed on the display unit when a specific image signal is input. Therefore, a desired color gamut conversion process is performed by changing the basic conversion matrix P.
  • the color gamut conversion process is performed after the white balance adjustment process.
  • the white balance of the image signal subjected to the color gamut conversion process deviates from the desired white balance.
  • the user has to repeat the fine adjustment of the white balance coefficient and the basic conversion matrix to realize desired white balance and color gamut conversion.
  • the chromaticity of the image displayed on the display unit can be changed by changing the white balance coefficient. Also had the problem of changing.
  • the present invention has been made in view of the above problems.
  • white balance adjustment processing and color gamut conversion processing are performed on an image signal, an image displayed on the display unit even when the white balance coefficient is changed.
  • An object of the present invention is to provide an image conversion apparatus capable of converting an image signal so that chromaticity does not change.
  • An image conversion apparatus is an image conversion apparatus that performs white balance adjustment processing and color gamut conversion processing on an image signal, and an acquisition unit that acquires a first image signal A conversion unit that generates a second image signal by performing white balance adjustment processing and color gamut conversion processing on the first image signal by one integrated conversion processing;
  • the white balance adjustment process and the color gamut conversion process for the first image signal can be performed by one integrated conversion process. Therefore, it is possible to prevent the white balance of the image signal from deviating from the desired white balance after the color gamut conversion processing. Furthermore, it is possible to suppress a change in chromaticity of an image displayed on the display unit when the white balance coefficient is changed.
  • the conversion unit based on the basic conversion matrix for converting the color gamut of the first image signal to the target color gamut, and the first white balance coefficient indicating the target white balance, Preferably, one integrated conversion process is performed.
  • the conversion unit includes a coefficient calculation unit that calculates a second white balance coefficient by multiplying the first white balance coefficient and an inverse matrix of the basic conversion matrix, and the calculated second white balance coefficient. It is preferable to include a conversion processing unit that converts the first image signal into the second image signal based on a balance coefficient and the basic conversion matrix.
  • the second white balance coefficient obtained by multiplying the first white balance coefficient and the inverse matrix of the basic conversion matrix and the integrated conversion matrix obtained from the basic conversion matrix are used.
  • One image signal can be converted into a second image signal. That is, since the white balance adjustment process and the color gamut conversion process can be performed by one integrated conversion process, the white balance of the image signal is prevented from deviating from a desired white balance after the color gamut conversion process. It becomes possible. Furthermore, by performing the conversion process using the second white balance coefficient, it is also possible to suppress a change in chromaticity of the image displayed on the display unit when the first white balance coefficient is changed. .
  • the acquisition unit includes an RGB conversion unit that converts a color space of an input image signal from a YUV color space to an RGB color space, and an RGB color space by the RGB conversion unit based on a predetermined first gamma curve. It is preferable to include a first inverse gamma correction unit that obtains the first image signal by performing inverse gamma correction on the input image signal converted to.
  • a gamma correction unit that performs gamma correction of the second image signal based on a predetermined second gamma curve, and the gamma correction unit based on a predetermined third gamma curve.
  • a second reverse gamma correction unit that performs reverse gamma correction on the second image signal that has been gamma corrected by the above-described method.
  • a gamma curve selection unit that selects a comma curve from a plurality of gamma curves held in advance, and a gamma curve adjustment unit that adjusts a part of the selected gamma curve.
  • At least one of an inverse gamma correction unit, the gamma correction unit, and the second reverse gamma correction unit is configured to perform the gamma correction or the reverse gamma correction based on the gamma curve adjusted by the gamma curve adjustment unit. It is preferable to carry out.
  • the gamma curve can be adjusted, so that it is possible to deal with dealer calibration.
  • the image conversion device may be configured as an integrated circuit.
  • the present invention can be realized not only as such an image conversion apparatus, but also as an image conversion method in which the operation of the characteristic components included in such an image conversion apparatus is used as a step.
  • the present invention can also be realized as a program for causing a computer to execute each step included in the image conversion method.
  • Such a program can be distributed via a non-temporary recording medium such as a CD-ROM (Compact Disc Only Memory) or a transmission medium such as the Internet.
  • the chromaticity of the image displayed on the display unit does not change even if the white balance coefficient is changed.
  • the signal can be converted.
  • FIG. 1 is an external view of an image conversion system according to Embodiment 1 of the present invention.
  • FIG. 2 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 1 of the present invention.
  • FIG. 3 is a flowchart showing the operation of the image conversion apparatus according to Embodiment 1 of the present invention.
  • FIG. 4 is a diagram for explaining the effect of the image conversion apparatus according to the first embodiment of the present invention.
  • FIG. 5 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 2 of the present invention.
  • FIG. 6 is a diagram for explaining an example of gamma curve adjustment in the image conversion apparatus according to the second embodiment of the present invention.
  • FIG. 7 is a flowchart showing the flow of conventional white balance adjustment processing and color gamut conversion processing.
  • FIG. 1 is an external view of an image conversion system according to Embodiment 1 of the present invention.
  • FIG. 2 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 1 of the present invention.
  • the image conversion system includes a display device 10 and an imaging device 20.
  • the imaging device 20 will be described.
  • the imaging device 20 is, for example, a digital video camera.
  • the imaging device 20 captures an image or a moving image and outputs an image signal.
  • the imaging device 20 includes an imaging unit 201, a gamma correction unit 202, and a YUV conversion unit 203.
  • the imaging unit 201 includes an optical system and an imaging element, and captures an image.
  • the captured image is output to the gamma correction unit 202 as an RGB signal.
  • the gamma correction unit 202 performs gamma correction on the RGB signal output from the imaging unit 201 based on a predetermined gamma curve.
  • a predetermined gamma curve for example, a gamma curve for CRT (Cathode Ray Tube) is used.
  • the YUV conversion unit 203 converts the color space of the RGB signal subjected to gamma correction from the RGB color space to the YUV (YPbPr) color space. That is, the YUV conversion unit 203 converts the RGB signal into a YUV signal.
  • the YUV conversion unit 203 is, for example, ITU-R BT.
  • the RGB signal is converted into a YUV signal so as to conform to the 709 standard.
  • the YUV signal thus converted is transmitted from the imaging device 20 to the display device 10 as an input image signal.
  • the input image signal transmission medium is not particularly limited, and for example, wired communication, wireless communication, broadcasting, or a recording medium can be used.
  • the display device 10 is, for example, a liquid crystal display or a plasma display.
  • the display device 10 includes an image conversion device 100, a display unit 106, a white balance coefficient input unit 107, and a basic conversion matrix input unit 108.
  • the image conversion apparatus 100 performs at least white balance adjustment processing and color gamut conversion processing on the input image signal. As illustrated in FIG. 2, the image conversion apparatus 100 includes an acquisition unit 110, a conversion unit 103, a gamma correction unit 104, and a second inverse gamma correction unit 105.
  • the acquisition unit 110 acquires the first image signal.
  • This first image signal is an RGB signal.
  • acquisition unit 110 acquires the first image signal based on the input image signal.
  • the acquisition unit 110 includes an RGB conversion unit 101 and a first inverse gamma correction unit 102.
  • the RGB conversion unit 101 converts the color space of the input image signal from the YUV color space to the RGB color space. That is, the RGB conversion unit 101 converts the YUV signal into an RGB signal.
  • the first inverse gamma correction unit 102 performs inverse gamma correction on the input image signal converted into the RGB color space by the RGB conversion unit 101 based on a predetermined first gamma curve.
  • inverse gamma correction refers to correcting an image signal so as to cancel the effect of gamma correction.
  • the first inverse gamma correction unit 102 removes the gamma curve applied to the image signal by the imaging device 20, and makes the signal characteristics of the image signal linear.
  • the RGB signal subjected to inverse gamma correction in this way is output to the conversion unit 103 as the first image signal.
  • the white balance coefficient input unit 107 receives an input of the first white balance coefficient. Specifically, the white balance coefficient input unit 107, for example, from among a plurality of first white balance coefficients ( ⁇ , ⁇ , ⁇ ) held in one-to-one correspondence with a plurality of color temperatures by the user. The first white balance coefficient ( ⁇ , ⁇ , ⁇ ) corresponding to the selected color temperature is accepted as an input. Further, for example, the white balance coefficient input unit 107 may accept an input of the value of the first white balance coefficient ( ⁇ , ⁇ , ⁇ ) from the user.
  • the first white balance coefficient is a conversion coefficient for adjusting white to a specific color temperature.
  • the first white balance coefficient is a combination of coefficients of each color indicating the relationship between the image signal before white balance adjustment and the image signal after white balance adjustment.
  • the first white balance coefficient is ( ⁇ , ⁇ , ⁇ )
  • an image signal having a RGB signal level ratio of 1: 1: 1 has an RGB signal level ratio of ⁇ : ⁇ : ⁇ . It should be adjusted so as to be an image signal.
  • the white balance coefficient input unit 107 does not necessarily receive an input from the user.
  • the white balance coefficient input unit 107 may receive, as an input, the first white balance coefficient that is automatically determined according to the color temperature of the illumination detected by a sensor installed in the vicinity of the display unit 106. Good.
  • the basic conversion matrix input unit 108 receives an input of a basic conversion matrix.
  • the basic transformation matrix input unit 108 uses, for example, a transformation matrix adjusted by the user so that the chromaticity when the monochrome image signal is displayed on the display unit 106 becomes the target chromaticity. Accept as input of transformation matrix.
  • the basic conversion matrix is a matrix for converting the color gamut of the image signal to the target color gamut.
  • the basic transformation matrix is ITU-R BT. This is a matrix for converting an image signal generated according to the 709 standard into an image signal having a color gamut suitable for the characteristics of the display unit 106.
  • the basic transformation matrix input unit 108 does not necessarily receive an input from the user.
  • the basic conversion matrix input unit 108 may accept as input the basic conversion matrix that is automatically set according to the chromaticity of the color that is detected by the sensor and displayed on the display unit 106. .
  • the conversion unit 103 generates a second image signal by performing a white balance adjustment process and a color gamut conversion process on the first image signal by one integrated conversion process using a calculation formula described later. To do. That is, the conversion unit 103 performs the white balance adjustment process and the color gamut conversion process on the first image signal simultaneously in one conversion process. Specifically, the conversion unit 103 performs the white balance adjustment process and the color gamut conversion process for the first image signal based on the basic conversion matrix and the first white balance coefficient as one integrated conversion process. Do.
  • the conversion unit 103 includes a coefficient calculation unit 103a and a conversion processing unit 103b.
  • the coefficient calculation unit 103a calculates the second white balance coefficient by multiplying the inverse matrix of the basic conversion matrix by the first white balance coefficient. Specifically, the coefficient calculation unit 103a includes the inverse matrix P ⁇ 1 of the basic conversion matrix P received by the basic conversion matrix input unit 108 and the first white balance coefficient ( ⁇ , The second white balance coefficient ( ⁇ ′, ⁇ ′, ⁇ ′) is calculated by multiplying by ⁇ , ⁇ ). Details of the processing of the coefficient calculation unit 103a will be described in detail with reference to FIG.
  • the conversion processing unit 103b converts the first image signal into the second image signal using an integrated conversion matrix obtained from the calculated second white balance coefficient and the basic conversion matrix. That is, the conversion processing unit 103b converts the first image signal into the second image signal using one integrated conversion matrix generated based on the second white balance coefficient and the basic conversion matrix. Details of the processing of the conversion processing unit 103b will be described in detail with reference to FIG.
  • the second image signal generated in this way is output to the gamma correction unit 104.
  • the gamma correction unit 104 performs gamma correction on the second image signal based on a predetermined second gamma curve. That is, the gamma correction unit 104 applies the second gamma curve to the second image signal.
  • the gamma-corrected image signal is output to the second inverse gamma correction unit 105.
  • the second gamma curve is preferably the same as the gamma curve used in the gamma correction in the imaging device 20.
  • the second inverse gamma correction unit 105 performs inverse gamma correction on the image signal that has been gamma corrected by the gamma correction unit 104 based on a predetermined third gamma curve.
  • the second inverse gamma correction unit 105 removes the gamma curve from the image signal output from the gamma correction unit 104 and makes the signal characteristics linear.
  • the image signal subjected to inverse gamma correction in this way is output to the display unit 106.
  • the display unit 106 displays the image signal on a screen such as a display.
  • FIG. 3 is a flowchart showing the operation of the image conversion apparatus 100 according to Embodiment 1 of the present invention.
  • the acquisition unit 110 acquires a first image signal (S101). Specifically, in step S101, the RGB conversion unit 101 converts the color space of the input image signal from the YUV color space to the RGB color space (S101a). Subsequently, the first inverse gamma correction unit 102 performs inverse gamma correction on the image signal converted into the RGB signal by the RGB conversion unit 101 based on a predetermined first gamma curve (S101b).
  • the conversion unit 103 generates a second image signal by performing white balance adjustment processing and color gamut conversion processing on the first image signal by one integrated conversion processing (S102).
  • step S102 the coefficient calculation unit 103a multiplies the inverse matrix P ⁇ 1 of the basic transformation matrix and the first white balance coefficient ( ⁇ , ⁇ , ⁇ ) as shown in (Equation 4).
  • the second white balance coefficient ( ⁇ ′, ⁇ ′, ⁇ ′) is calculated (S102a).
  • the conversion processing unit 103b uses the integrated conversion matrix P ′ to convert the first image signal (r in , g in , b in ) into the second image signal (r out , g out , b out ) (S102b).
  • the integrated transformation matrix P ′ is a matrix generated based on the second white balance coefficients ( ⁇ ′, ⁇ ′, ⁇ ′) and the basic transformation matrix P as shown in (Equation 6). . That is, by using the integrated conversion matrix P ′, the white balance adjustment process and the color gamut conversion process can be performed by one conversion process.
  • the conversion processing unit 103b converts the first image signal into the second image signal based on the second white balance coefficient and the basic conversion matrix.
  • the gamma correction unit 104 performs gamma correction on the second image signal based on a predetermined second gamma curve (S103).
  • the second inverse gamma correction unit 105 performs reverse gamma correction on the image signal that has been gamma corrected by the gamma correction unit 104 based on a predetermined third gamma curve (S104).
  • the image conversion apparatus 100 generates the second image signal by performing the white balance adjustment process and the color gamut conversion process on the first image signal by one integrated conversion process.
  • Equation 4 By transforming (Equation 7), (Equation 4) is derived. That is, the target white balance is realized by performing the conversion process based on the second white balance coefficient calculated by (Equation 4). This point will be described in detail.
  • the component of the second white balance coefficient ( ⁇ ′, ⁇ ′, ⁇ ′) includes an inverse matrix of the basic transformation matrix P. Accordingly, multiplication of P and P ⁇ 1 is performed in the calculation process in (Equation 7). As a result, the multiplication of P and P ⁇ 1 is a unit matrix.
  • the integrated transformation matrix P ′ becomes equal to the first white balance coefficient ( ⁇ , ⁇ , ⁇ ).
  • the second image signal is a function of the first white balance coefficient ( ⁇ , ⁇ , ⁇ ) and does not depend on the basic transformation matrix P. In conclusion, adjusting the basic transformation matrix does not change the target white balance.
  • the chromaticity of the second image signal (r out , g out , b out ) does not depend on the second white balance coefficient ( ⁇ ′, ⁇ ′, ⁇ ′).
  • the second white balance coefficient ( ⁇ ′, ⁇ ′, ⁇ ′) is determined based on the first white balance coefficient ( ⁇ , ⁇ , ⁇ ) (Formula 4). Therefore, the chromaticity of the second image signal (r out , g out , b out ) does not depend on the first white balance coefficient ( ⁇ , ⁇ , ⁇ ). In other words, even if the first white balance coefficient is adjusted, the second image signal does not change.
  • FIG. 4 is a diagram for explaining the effect of the image conversion apparatus 100 according to Embodiment 1 of the present invention.
  • FIG. 4A shows the measurement result of the chromaticity of the image displayed on the display unit when the first white balance coefficient is changed in the conventional image conversion apparatus.
  • FIG. 4B shows the measurement result of the chromaticity of the image displayed on the display unit when the first white balance coefficient is changed in the image conversion apparatus 100 according to the present embodiment. Note that the basic transformation matrix is not changed for all measurement results.
  • “High”, “Mid”, and “Low” correspond to the first white balance coefficient. Specifically, “High”, “Mid”, and “Low” are first white balance coefficients set so that the color temperatures are “11500K”, “9500K”, and “6500K”.
  • FIG. 4 shows the chromaticity measured when the white balance adjustment process and the color gamut conversion process are performed on the RGB single-color image signals.
  • the conventional image conversion apparatus uses chromaticity (x, y). Is (0.642, 0.330).
  • the color difference ⁇ E is a value for representing the difference between the target chromaticity and the chromaticity of the measurement result.
  • FIG. 4 shows the color difference ⁇ E having the largest value among the chromaticities corresponding to the three first white balance coefficients.
  • the change in chromaticity when the first white balance coefficient is changed is suppressed more than in the past.
  • this embodiment is “0.304” compared to the conventional “2.696”, and in this embodiment, the chromaticity is about nine times that of the conventional one. Is stable.
  • the image conversion apparatus 100 when the white balance adjustment process and the color gamut conversion process are performed on the image signal, the image conversion apparatus 100 according to the present embodiment changes the white balance coefficient more than before. However, the image signal can be converted so that the chromaticity of the image displayed on the display unit 106 does not change.
  • the white balance adjustment process and the color gamut conversion process for the first image signal can be performed by one integrated conversion process. Therefore, it is possible to prevent the white balance of the image signal from deviating from the desired white balance after the color gamut conversion processing. Furthermore, it is possible to suppress a change in chromaticity of an image displayed on the display unit when the white balance coefficient is changed.
  • the second white balance coefficient obtained by multiplying the first white balance coefficient and the inverse matrix of the basic conversion matrix, and the basic conversion matrix are used.
  • the first image signal can be converted into the second image signal by using the obtained integrated conversion matrix. That is, since the white balance adjustment process and the color gamut conversion process can be performed by one integrated conversion process, the white balance of the image signal is prevented from deviating from a desired white balance after the color gamut conversion process. It becomes possible. Furthermore, by performing the conversion process using the second white balance coefficient, it is also possible to suppress a change in chromaticity of the image displayed on the display unit when the first white balance coefficient is changed. .
  • the image conversion apparatus 100 since the image conversion apparatus 100 according to the present embodiment includes the RGB conversion unit 101, white balance adjustment processing and color gamut conversion processing can be performed even when the input image signal is a YUV signal. Further, the image conversion apparatus 100 performs inverse gamma correction before the white balance adjustment process and the color gamut conversion process. Therefore, white balance adjustment processing and color gamut conversion processing can be performed with high accuracy on an image signal having linear signal characteristics, and a change in chromaticity of an image displayed on the display unit can be suppressed. Become.
  • the input image signal is a gamma-corrected YUV signal, but it is not necessarily such a signal.
  • the input image signal may be an RGB signal that has not been gamma corrected.
  • the acquisition unit 110 does not need to include the RGB conversion unit 101 and the first inverse gamma correction unit 102. That is, the acquisition unit 110 may acquire the input image signal as the first image signal.
  • the image conversion apparatus 100 does not need to include the gamma correction unit 104 and the second inverse gamma correction unit 105. That is, the image conversion apparatus 100 may output the second image signal to the display unit 106 as an output image signal.
  • FIG. 5 is a block diagram showing a functional configuration of the image conversion system according to the second embodiment of the present invention.
  • the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
  • the image conversion apparatus 150 includes a gamma curve selection unit 151 and a gamma curve adjustment unit 152 in addition to the components shown in FIG.
  • the gamma curve selection unit 151 selects a gamma curve from a plurality of gamma curves held in advance. Specifically, the gamma curve selection unit 151 selects a gamma curve based on an input from a user received by an input unit (not shown), for example. Further, for example, the gamma curve selection unit 151 may analyze the input image signal and select a gamma curve adapted to the input image signal.
  • the gamma curve adjustment unit 152 adjusts a part of the selected gamma curve. Specifically, the gamma curve adjustment unit 152 finely adjusts a part of the gamma curve based on the input from the user received by the input unit, for example. For example, the gamma curve adjustment unit 152 may analyze the input image signal and adjust a part of the gamma curve so as to adapt to the input image signal.
  • At least one of the first inverse gamma correction unit 102, the gamma correction unit 104, and the second reverse gamma correction unit 105 performs gamma correction or reverse gamma correction based on the gamma curve adjusted by the gamma curve adjustment unit 152. I do.
  • FIG. 6 is a diagram for explaining an example of gamma curve adjustment in the image conversion apparatus 150 according to Embodiment 2 of the present invention.
  • the horizontal axis represents the input level
  • the vertical axis represents the output level.
  • the gamma curve 301 is divided into 16 with respect to the input level. Then, the user can adjust the dividing point 302 representing each divided portion up and down within the adjustable range 303.
  • the adjustable range 303 is a range of ⁇ 128 around the position of the division point 302 before adjustment when the upper limit value of the input level and output level is 1024. However, the adjustable range 303 has 0 as a lower limit and 1024 as an upper limit.
  • the user can adjust the gamma curve used for gamma correction or inverse gamma correction, and it is possible to deal with dealer calibration.
  • the image conversion apparatus 100 has been described based on the embodiments.
  • the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which carried out various deformation
  • the image conversion apparatuses 100 and 150 are included in the display apparatus 10, but are not necessarily included in the display apparatus 10.
  • a BD player or a set top box that does not include a display unit may include the image conversion apparatuses 100 and 150.
  • the input image signal is an image signal generated by the imaging device 20, but the input image signal does not necessarily have to be generated by the imaging device 20.
  • the input image signal may be an image signal generated by a computer (so-called CG (Computer Graphics)).
  • the constituent elements included in the image conversion apparatus 100 according to the first or second embodiment may be configured by one system LSI (Large Scale Integration).
  • the image conversion apparatus 100 may be configured by a system LSI having an acquisition unit 110 and a conversion unit 103.
  • the system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip. Specifically, a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), etc. It is a computer system comprised including. A computer program is stored in the ROM. The system LSI achieves its functions by the microprocessor operating according to the computer program.
  • system LSI may be called IC, LSI, super LSI, or ultra LSI depending on the degree of integration.
  • method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible.
  • An FPGA Field Programmable Gate Array
  • reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
  • the present invention can be realized not only as an image conversion apparatus including such a characteristic processing unit, but also as an image conversion method using the characteristic processing unit included in the image conversion apparatus as a step. You can also. It can also be realized as a computer program that causes a computer to execute the characteristic steps included in the image conversion method. Needless to say, such a computer program can be distributed via a computer-readable non-transitory recording medium such as a CD-ROM or a communication network such as the Internet.
  • the image conversion apparatus can easily realize white balance adjustment and color gamut conversion, and can be used for any AV device that can output an image.

Abstract

In order that when white balance adjustment processing and color gamut conversion processing are performed, the change of the chromaticity of an image displayed by a display unit when the white balance coefficient is changed can be suppressed, disclosed is an image conversion device (100) for performing white balance adjustment processing and color gamut conversion processing on an image signal, said image conversion device being provided with an acquisition unit (110) which acquires a first image signal, and a conversion unit (103) which generates a second image signal by performing the white balance adjustment processing and the color gamut conversion processing for the acquired first image signal by one integrated conversion processing.

Description

画像変換装置及び画像変換方法Image conversion apparatus and image conversion method
　本発明は、入力画像信号を出力画像信号に変換する画像変換装置に関し、特に、画像信号に対してホワイトバランス調整処理及び色域変換処理を行う画像変換装置に関する。 The present invention relates to an image conversion apparatus that converts an input image signal into an output image signal, and more particularly to an image conversion apparatus that performs white balance adjustment processing and color gamut conversion processing on an image signal.
　一般的に、映像信号の色を再現する際に重要となるのは、ホワイトバランス及び色域である。従来の画像変換装置は、Ｇｒｅｅｎ（以下、単に「Ｇ」と記載する）アンプゲインを固定した状態で、Ｒｅｄ（以下、単に「Ｒ」と記載する）アンプゲインと、Ｂｌｕｅ（以下、単に「Ｂ」と記載する）アンプゲインと、黒レベルとを変化させることにより、ホワイトバランス調整処理を行う。 Generally, white balance and color gamut are important when reproducing the color of a video signal. In a conventional image conversion apparatus, a green (hereinafter simply referred to as “G”) amplifier gain is fixed, a red (hereinafter simply referred to as “R”) amplifier gain, and a blue (hereinafter simply referred to as “B”). The white balance adjustment process is performed by changing the amplifier gain and the black level.
　また、他の従来の画像変換装置は、Ｇアンプゲインを固定した状態で、Ｒアンプゲイン及びＢアンプゲインのみを変化させることにより、ホワイトバランス調整処理を行う（例えば、特許文献１参照）。 Other conventional image conversion apparatuses perform white balance adjustment processing by changing only the R amplifier gain and the B amplifier gain while the G amplifier gain is fixed (see, for example, Patent Document 1).
　図７は、従来の画像変換装置におけるホワイトバランス調整処理及び色域変換処理の流れを示すフローチャートである。 FIG. 7 is a flowchart showing the flow of white balance adjustment processing and color gamut conversion processing in a conventional image conversion apparatus.
　まず、Ｇ信号の信号レベルを固定とした状態で、Ｒ信号及びＢ信号の信号レベルの調整と、黒レベルの信号レベルの調整とが行われる（ステップＳ１００１）。その後、色域変換処理が行われる（ステップＳ１００２）。 First, with the signal level of the G signal fixed, the signal level of the R signal and the B signal are adjusted and the signal level of the black level is adjusted (step S1001). Thereafter, a color gamut conversion process is performed (step S1002).
　ここで、ホワイトバランス調整処理は、（式１）で表わされる。 Here, the white balance adjustment processing is expressed by (Equation 1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　α、β、γは、ホワイトバランス係数である。また、（ｒ，ｇ，ｂ）は、ホワイトバランス処理前の画像信号におけるＲＧＢそれぞれの信号レベルを示す。また、（ｒｉｎ，ｇｉｎ，ｂｉｎ）は、ホワイトバランス処理後の画像信号におけるＲＧＢそれぞれの信号レベルを示す。 α, β, and γ are white balance coefficients. Further, (r, g, b) indicates the signal levels of RGB in the image signal before white balance processing. Further, (r in , g in , b in ) indicates the respective RGB signal levels in the image signal after white balance processing.
　色域変換処理は、（式２）及び（式３）で表わされる。 Color gamut conversion processing is expressed by (Expression 2) and (Expression 3).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
　（ｒｏｕｔ，ｇｏｕｔ，ｂｏｕｔ）は、色域変換処理後の画像信号におけるＲＧＢの信号レベルを示す。（ｒｉｎ，ｇｉｎ，ｂｉｎ）は、ホワイトバランス調整処理後の画像信号（色域変換処理前の画像信号）におけるＲＧＢそれぞれの信号レベルを示す。 (R out , g out , b out ) indicates the RGB signal level in the image signal after the color gamut conversion processing. (R in , g in , b in ) indicate signal levels of RGB in the image signal after white balance adjustment processing (image signal before color gamut conversion processing).
　また、Ｐは、基本変換行列を示す。基本変換行列とは、特定の画像信号が入力されたときに目的の色度点の色を有する画像が表示部に表示されるように画像信号を調整するための行列である。したがって、この基本変換行列Ｐを変化させることにより、所望の色域変換処理が行われる。 P represents a basic transformation matrix. The basic conversion matrix is a matrix for adjusting the image signal so that an image having a target chromaticity point color is displayed on the display unit when a specific image signal is input. Therefore, a desired color gamut conversion process is performed by changing the basic conversion matrix P.
特開２００８－１６６９６４号公報JP 2008-166964 A
　しかしながら、上記従来の画像変換装置では、ホワイトバランス調整処理が行われた後に色域変換処理が行われる。その結果、色域変換処理が行われた画像信号のホワイトバランスが所望のホワイトバランスからずれてしまうという課題があった。このような場合、ユーザは、ホワイトバランス係数及び基本変換行列の微調整を繰り返して、所望のホワイトバランス及び色域変換を実現しなければならなかった。さらに、このようなホワイトバランス係数及び基本変換行列の微調整が完了した後に、再びホワイトバランス係数の変更が必要となった場合、ホワイトバランス係数を変更すれば表示部に表示される画像の色度も変化してしまうという課題も有していた。 However, in the conventional image conversion apparatus, the color gamut conversion process is performed after the white balance adjustment process. As a result, there has been a problem that the white balance of the image signal subjected to the color gamut conversion process deviates from the desired white balance. In such a case, the user has to repeat the fine adjustment of the white balance coefficient and the basic conversion matrix to realize desired white balance and color gamut conversion. Furthermore, if it is necessary to change the white balance coefficient again after completing the fine adjustment of the white balance coefficient and the basic conversion matrix, the chromaticity of the image displayed on the display unit can be changed by changing the white balance coefficient. Also had the problem of changing.
　本発明は、上記課題に鑑みてなされたもので、画像信号に対してホワイトバランス調整処理及び色域変換処理が行われる際に、ホワイトバランス係数を変化させても表示部に表示される画像の色度が変化しないように画像信号を変換することができる画像変換装置を提供することを目的とする。 The present invention has been made in view of the above problems. When white balance adjustment processing and color gamut conversion processing are performed on an image signal, an image displayed on the display unit even when the white balance coefficient is changed. An object of the present invention is to provide an image conversion apparatus capable of converting an image signal so that chromaticity does not change.
　本発明の一態様に係る画像変換装置は、画像信号に対してホワイトバランス調整処理及び色域変換処理を行う画像変換装置であって、第１の画像信号を取得する取得部と、取得された前記第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行うことにより、第２の画像信号を生成する変換部とを備える。 An image conversion apparatus according to an aspect of the present invention is an image conversion apparatus that performs white balance adjustment processing and color gamut conversion processing on an image signal, and an acquisition unit that acquires a first image signal A conversion unit that generates a second image signal by performing white balance adjustment processing and color gamut conversion processing on the first image signal by one integrated conversion processing;
　本構成によれば、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とが１つの統合された変換処理で行うことができる。したがって、色域変換処理後に、画像信号のホワイトバランスが所望のホワイトバランスからずれてしまうことを防ぐことが可能となる。さらに、ホワイトバランス係数を変化させたときに表示部に表示される画像の色度の変化を抑制することも可能となる。 According to this configuration, the white balance adjustment process and the color gamut conversion process for the first image signal can be performed by one integrated conversion process. Therefore, it is possible to prevent the white balance of the image signal from deviating from the desired white balance after the color gamut conversion processing. Furthermore, it is possible to suppress a change in chromaticity of an image displayed on the display unit when the white balance coefficient is changed.
　また、前記変換部は、前記第１の画像信号の色域を目的の色域に変換するための基本変換行列と、目的となるホワイトバランスを示す第１のホワイトバランス係数とに基づいて、前記１つの統合された変換処理を行うことが好ましい。 Further, the conversion unit, based on the basic conversion matrix for converting the color gamut of the first image signal to the target color gamut, and the first white balance coefficient indicating the target white balance, Preferably, one integrated conversion process is performed.
　本構成によれば、ホワイトバランス調整処理前の画像信号である第１の画像信号の色域を目的の色域に変換するための基本変換行列と第１のホワイトバランス係数とに基づいて、１つの統合された変換処理を行うことができる。 According to this configuration, based on the basic conversion matrix for converting the color gamut of the first image signal, which is the image signal before the white balance adjustment processing, to the target color gamut and the first white balance coefficient, 1 One integrated conversion process can be performed.
　また、前記変換部は、前記第１のホワイトバランス係数と前記基本変換行列の逆行列とを乗算することにより第２のホワイトバランス係数を算出する係数算出部と、算出された前記第２のホワイトバランス係数と前記基本変換行列とに基づいて、前記第１の画像信号を前記第２の画像信号に変換する変換処理部とを備えることが好ましい。 The conversion unit includes a coefficient calculation unit that calculates a second white balance coefficient by multiplying the first white balance coefficient and an inverse matrix of the basic conversion matrix, and the calculated second white balance coefficient. It is preferable to include a conversion processing unit that converts the first image signal into the second image signal based on a balance coefficient and the basic conversion matrix.
　本構成によれば、第１のホワイトバランス係数と基本変換行列の逆行列とを乗算することにより得られる第２のホワイトバランス係数と、基本変換行列とから得られる統合変換行列を用いて、第１の画像信号を第２の画像信号に変換することができる。つまり、ホワイトバランス調整処理と色域変換処理とが１つの統合された変換処理で行うことができるので、色域変換処理後に、画像信号のホワイトバランスが所望のホワイトバランスからずれてしまうことを防ぐことが可能となる。さらに、第２のホワイトバランス係数を用いて変換処理を行うことにより、第１のホワイトバランス係数を変化させたときに表示部に表示される画像の色度の変化を抑制することも可能となる。 According to this configuration, the second white balance coefficient obtained by multiplying the first white balance coefficient and the inverse matrix of the basic conversion matrix and the integrated conversion matrix obtained from the basic conversion matrix are used. One image signal can be converted into a second image signal. That is, since the white balance adjustment process and the color gamut conversion process can be performed by one integrated conversion process, the white balance of the image signal is prevented from deviating from a desired white balance after the color gamut conversion process. It becomes possible. Furthermore, by performing the conversion process using the second white balance coefficient, it is also possible to suppress a change in chromaticity of the image displayed on the display unit when the first white balance coefficient is changed. .
　また、前記取得部は、入力画像信号の色空間をＹＵＶ色空間からＲＧＢ色空間に変換するＲＧＢ変換部と、予め定められた第１のガンマカーブに基づいて、前記ＲＧＢ変換部によってＲＧＢ色空間に変換された入力画像信号の逆ガンマ補正を行うことにより、前記第１の画像信号を取得する第１の逆ガンマ補正部とを備えることが好ましい。 The acquisition unit includes an RGB conversion unit that converts a color space of an input image signal from a YUV color space to an RGB color space, and an RGB color space by the RGB conversion unit based on a predetermined first gamma curve. It is preferable to include a first inverse gamma correction unit that obtains the first image signal by performing inverse gamma correction on the input image signal converted to.
　本構成によれば、入力画像信号がＹＵＶ信号である場合にも、ホワイトバランス調整処理及び色域変換処理を行うことができる。さらに、ホワイトバランス調整処理及び色域変換処理が行われる前に逆ガンマ補正が行われる。したがって、リニアな信号特性を有する画像信号に対してホワイトバランス調整処理及び色域変換処理を高精度に行うことができ、表示部に表示される画像の色度の変化を抑制することも可能となる。 According to this configuration, even when the input image signal is a YUV signal, white balance adjustment processing and color gamut conversion processing can be performed. Further, inverse gamma correction is performed before the white balance adjustment process and the color gamut conversion process are performed. Therefore, white balance adjustment processing and color gamut conversion processing can be performed with high accuracy on an image signal having linear signal characteristics, and a change in chromaticity of an image displayed on the display unit can be suppressed. Become.
　また、さらに、予め定められた第２のガンマカーブに基づいて、前記第２の画像信号のガンマ補正を行うガンマ補正部と、予め定められた第３のガンマカーブに基づいて、前記ガンマ補正部によってガンマ補正された第２の画像信号の逆ガンマ補正を行う第２の逆ガンマ補正部とを備える。 Further, a gamma correction unit that performs gamma correction of the second image signal based on a predetermined second gamma curve, and the gamma correction unit based on a predetermined third gamma curve. And a second reverse gamma correction unit that performs reverse gamma correction on the second image signal that has been gamma corrected by the above-described method.
　また、さらに、予め保持された複数のガンマカーブの中からカンマカーブを選択するガンマカーブ選択部と、選択された前記ガンマカーブの一部を調整するガンマカーブ調整部とを備え、前記第１の逆ガンマ補正部、前記ガンマ補正部、及び前記第２の逆ガンマ補正部のうちの少なくとも１つは、前記ガンマカーブ調整部によって調整されたガンマカーブに基づいて、前記ガンマ補正又は前記逆ガンマ補正を行うことが好ましい。 And a gamma curve selection unit that selects a comma curve from a plurality of gamma curves held in advance, and a gamma curve adjustment unit that adjusts a part of the selected gamma curve. At least one of an inverse gamma correction unit, the gamma correction unit, and the second reverse gamma correction unit is configured to perform the gamma correction or the reverse gamma correction based on the gamma curve adjusted by the gamma curve adjustment unit. It is preferable to carry out.
　本構成によれば、ガンマカーブを調整することが可能となるので、ディーラーキャリブレーションに対応することが可能となる。 According to this configuration, the gamma curve can be adjusted, so that it is possible to deal with dealer calibration.
　また、前記画像変換装置は、集積回路として構成されてもよい。 Further, the image conversion device may be configured as an integrated circuit.
　なお、本発明は、このような画像変換装置として実現することができるだけでなく、このような画像変換装置が備える特徴的な構成部の動作をステップとする画像変換方法として実現することができる。また、本発明は、画像変換方法に含まれる各ステップをコンピュータに実行させるプログラムとして実現することもできる。そして、そのようなプログラムは、ＣＤ－ＲＯＭ（Ｃｏｍｐａｃｔ　Ｄｉｓｃ　Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）等の非一時的な記録媒体あるいはインターネット等の伝送媒体を介して配信することができるのは言うまでもない。 It should be noted that the present invention can be realized not only as such an image conversion apparatus, but also as an image conversion method in which the operation of the characteristic components included in such an image conversion apparatus is used as a step. The present invention can also be realized as a program for causing a computer to execute each step included in the image conversion method. Such a program can be distributed via a non-temporary recording medium such as a CD-ROM (Compact Disc Only Memory) or a transmission medium such as the Internet.
　本発明によれば、画像信号に対してホワイトバランス調整処理及び色域変換処理が行われる際に、ホワイトバランス係数を変化させても表示部に表示される画像の色度が変化しないように画像信号を変換することができる。 According to the present invention, when the white balance adjustment process and the color gamut conversion process are performed on the image signal, the chromaticity of the image displayed on the display unit does not change even if the white balance coefficient is changed. The signal can be converted.
図１は、本発明の実施の形態１に係る画像変換システムの外観図である。FIG. 1 is an external view of an image conversion system according to Embodiment 1 of the present invention. 図２は、本発明の実施の形態１に係る画像変換システムの機能構成を示すブロック図である。FIG. 2 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 1 of the present invention. 図３は、本発明の実施の形態１に係る画像変換装置の動作を示すフローチャートである。FIG. 3 is a flowchart showing the operation of the image conversion apparatus according to Embodiment 1 of the present invention. 図４は、本発明の実施の形態１に係る画像変換装置の効果を説明するための図である。FIG. 4 is a diagram for explaining the effect of the image conversion apparatus according to the first embodiment of the present invention. 図５は、本発明の実施の形態２に係る画像変換システムの機能構成を示すブロック図である。FIG. 5 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 2 of the present invention. 図６は、本発明の実施の形態２に係る画像変換装置におけるガンマカーブ調整の一例を説明するための図である。FIG. 6 is a diagram for explaining an example of gamma curve adjustment in the image conversion apparatus according to the second embodiment of the present invention. 図７は、従来のホワイトバランス調整処理及び色域変換処理の流れを示すフローチャートである。FIG. 7 is a flowchart showing the flow of conventional white balance adjustment processing and color gamut conversion processing.
　以下本発明の実施の形態について、図面を参照しながら説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　（実施の形態１）
　図１は、本発明の実施の形態１に係る画像変換システムの外観図である。また、図２は、本発明の実施の形態１に係る画像変換システムの機能構成を示すブロック図である。図１及び図２に示すように、画像変換システムは、表示装置１０と撮像装置２０とを備える。 (Embodiment 1)
FIG. 1 is an external view of an image conversion system according to Embodiment 1 of the present invention. FIG. 2 is a block diagram showing a functional configuration of the image conversion system according to Embodiment 1 of the present invention. As shown in FIGS. 1 and 2, the image conversion system includes a display device 10 and an imaging device 20.
　まず、撮像装置２０について説明する。 First, the imaging device 20 will be described.
　撮像装置２０は、例えばデジタルビデオカメラなどである。撮像装置２０は、画像あるいは動画像を撮影して、画像信号を出力する。図２に示すように、撮像装置２０は、撮像部２０１と、ガンマ補正部２０２と、ＹＵＶ変換部２０３とを備える。 The imaging device 20 is, for example, a digital video camera. The imaging device 20 captures an image or a moving image and outputs an image signal. As illustrated in FIG. 2, the imaging device 20 includes an imaging unit 201, a gamma correction unit 202, and a YUV conversion unit 203.
　撮像部２０１は、光学系及び撮像素子などを備え、画像を撮影する。撮影された画像は、ＲＧＢ信号としてガンマ補正部２０２に出力される。 The imaging unit 201 includes an optical system and an imaging element, and captures an image. The captured image is output to the gamma correction unit 202 as an RGB signal.
　ガンマ補正部２０２は、予め定められたガンマカーブに基づいて、撮像部２０１から出力されたＲＧＢ信号をガンマ補正する。予め定められた第１のガンマカーブとしては、例えば、ＣＲＴ（Ｃａｔｈｏｄｅ　Ｒａｙ　Ｔｕｂｅ）用のガンマカーブが用いられる。 The gamma correction unit 202 performs gamma correction on the RGB signal output from the imaging unit 201 based on a predetermined gamma curve. As the predetermined first gamma curve, for example, a gamma curve for CRT (Cathode Ray Tube) is used.
　ＹＵＶ変換部２０３は、ガンマ補正されたＲＧＢ信号の色空間をＲＧＢ色空間からＹＵＶ（ＹＰｂＰｒ）色空間に変換する。つまり、ＹＵＶ変換部２０３は、ＲＧＢ信号をＹＵＶ信号に変換する。具体的には、ＹＵＶ変換部２０３は、例えばＩＴＵ－Ｒ　ＢＴ．７０９規格に適合するように、ＲＧＢ信号をＹＵＶ信号に変換する。 The YUV conversion unit 203 converts the color space of the RGB signal subjected to gamma correction from the RGB color space to the YUV (YPbPr) color space. That is, the YUV conversion unit 203 converts the RGB signal into a YUV signal. Specifically, the YUV conversion unit 203 is, for example, ITU-R BT. The RGB signal is converted into a YUV signal so as to conform to the 709 standard.
　このように変換されたＹＵＶ信号は、入力画像信号として撮像装置２０から表示装置１０に伝達される。なお、入力画像信号の伝達媒体としては、特に限定される必要はなく、例えば有線通信、無線通信、放送、又は記録媒体などを用いることができる。 The YUV signal thus converted is transmitted from the imaging device 20 to the display device 10 as an input image signal. The input image signal transmission medium is not particularly limited, and for example, wired communication, wireless communication, broadcasting, or a recording medium can be used.
　次に、表示装置１０について説明する。 Next, the display device 10 will be described.
　表示装置１０は、例えば液晶ディスプレイあるいはプラズマディスプレイなどである。表示装置１０は、画像変換装置１００と、表示部１０６と、ホワイトバランス係数入力部１０７と、基本変換行列入力部１０８とを備える。 The display device 10 is, for example, a liquid crystal display or a plasma display. The display device 10 includes an image conversion device 100, a display unit 106, a white balance coefficient input unit 107, and a basic conversion matrix input unit 108.
　画像変換装置１００は、入力画像信号に対して、少なくともホワイトバランス調整処理及び色域変換処理を行う。図２に示すように、画像変換装置１００は、取得部１１０と、変換部１０３と、ガンマ補正部１０４と、第２の逆ガンマ補正部１０５とを備える。 The image conversion apparatus 100 performs at least white balance adjustment processing and color gamut conversion processing on the input image signal. As illustrated in FIG. 2, the image conversion apparatus 100 includes an acquisition unit 110, a conversion unit 103, a gamma correction unit 104, and a second inverse gamma correction unit 105.
　取得部１１０は、第１の画像信号を取得する。この第１の画像信号は、ＲＧＢ信号である。本実施の形態では、取得部１１０は、入力画像信号に基づいて第１の画像信号を取得する。取得部１１０は、ＲＧＢ変換部１０１と第１の逆ガンマ補正部１０２とを備える。 The acquisition unit 110 acquires the first image signal. This first image signal is an RGB signal. In the present embodiment, acquisition unit 110 acquires the first image signal based on the input image signal. The acquisition unit 110 includes an RGB conversion unit 101 and a first inverse gamma correction unit 102.
　ＲＧＢ変換部１０１は、入力画像信号の色空間をＹＵＶ色空間からＲＧＢ色空間に変換する。つまり、ＲＧＢ変換部１０１は、ＹＵＶ信号をＲＧＢ信号に変換する。 The RGB conversion unit 101 converts the color space of the input image signal from the YUV color space to the RGB color space. That is, the RGB conversion unit 101 converts the YUV signal into an RGB signal.
　第１の逆ガンマ補正部１０２は、予め定められた第１のガンマカーブに基づいて、ＲＧＢ変換部１０１によってＲＧＢ色空間に変換された入力画像信号を逆ガンマ補正する。ここで、逆ガンマ補正とは、ガンマ補正による効果を相殺するように画像信号を補正することをいう。 The first inverse gamma correction unit 102 performs inverse gamma correction on the input image signal converted into the RGB color space by the RGB conversion unit 101 based on a predetermined first gamma curve. Here, inverse gamma correction refers to correcting an image signal so as to cancel the effect of gamma correction.
　つまり、第１の逆ガンマ補正部１０２は、撮像装置２０によって画像信号にかけられたガンマカーブを取り除き、画像信号の信号特性をリニアな状態にする。このように逆ガンマ補正されたＲＧＢ信号は、第１の画像信号として変換部１０３へ出力される。 That is, the first inverse gamma correction unit 102 removes the gamma curve applied to the image signal by the imaging device 20, and makes the signal characteristics of the image signal linear. The RGB signal subjected to inverse gamma correction in this way is output to the conversion unit 103 as the first image signal.
　ホワイトバランス係数入力部１０７は、第１のホワイトバランス係数の入力を受け付ける。具体的には、ホワイトバランス係数入力部１０７は、例えば、複数の色温度に一対一で対応づけて保持された複数の第１のホワイトバランス係数（α，β，γ）の中から、ユーザによって選択された色温度に対応する第１のホワイトバランス係数（α，β，γ）を入力として受け付ける。また例えば、ホワイトバランス係数入力部１０７は、第１のホワイトバランス係数（α，β，γ）の値の入力をユーザから受け付けてもよい。 The white balance coefficient input unit 107 receives an input of the first white balance coefficient. Specifically, the white balance coefficient input unit 107, for example, from among a plurality of first white balance coefficients (α, β, γ) held in one-to-one correspondence with a plurality of color temperatures by the user. The first white balance coefficient (α, β, γ) corresponding to the selected color temperature is accepted as an input. Further, for example, the white balance coefficient input unit 107 may accept an input of the value of the first white balance coefficient (α, β, γ) from the user.
　ここで、第１のホワイトバランス係数とは、白色を特定の色温度に調整するための変換係数である。言い換えれば、第１のホワイトバランス係数とは、ホワイトバランス調整前の画像信号とホワイトバランス調整後の画像信号との関係を示す各色の係数の組合せである。例えば、第１のホワイトバランス係数が（α，β，γ）である場合、ＲＧＢの信号レベルの比が１：１：１である画像信号は、ＲＧＢの信号レベルの比がα：β：γの画像信号となるように調整されるべきであることを示す。 Here, the first white balance coefficient is a conversion coefficient for adjusting white to a specific color temperature. In other words, the first white balance coefficient is a combination of coefficients of each color indicating the relationship between the image signal before white balance adjustment and the image signal after white balance adjustment. For example, when the first white balance coefficient is (α, β, γ), an image signal having a RGB signal level ratio of 1: 1: 1 has an RGB signal level ratio of α: β: γ. It should be adjusted so as to be an image signal.
　なお、ホワイトバランス係数入力部１０７は、必ずしもユーザから入力を受け付ける必要はない。例えば、ホワイトバランス係数入力部１０７は、表示部１０６の近傍に設置されたセンサによって検知された照明の色温度などに応じて自動的に決定された第１のホワイトバランス係数を入力として受け付けてもよい。 Note that the white balance coefficient input unit 107 does not necessarily receive an input from the user. For example, the white balance coefficient input unit 107 may receive, as an input, the first white balance coefficient that is automatically determined according to the color temperature of the illumination detected by a sensor installed in the vicinity of the display unit 106. Good.
　基本変換行列入力部１０８は、基本変換行列の入力を受け付ける。具体的には、基本変換行列入力部１０８は、例えば、単色の画像信号が表示部１０６に表示されたときの色度が目的の色度となるようにユーザによって調整された変換行列を、基本変換行列の入力として受け付ける。 The basic conversion matrix input unit 108 receives an input of a basic conversion matrix. Specifically, the basic transformation matrix input unit 108 uses, for example, a transformation matrix adjusted by the user so that the chromaticity when the monochrome image signal is displayed on the display unit 106 becomes the target chromaticity. Accept as input of transformation matrix.
　ここで、基本変換行列とは、画像信号の色域を目的の色域に変換するための行列である。例えば、基本変換行列は、ＩＴＵ－Ｒ　ＢＴ．７０９規格に従って生成された画像信号を、表示部１０６の特性に適した色域の画像信号に変換するための行列である。 Here, the basic conversion matrix is a matrix for converting the color gamut of the image signal to the target color gamut. For example, the basic transformation matrix is ITU-R BT. This is a matrix for converting an image signal generated according to the 709 standard into an image signal having a color gamut suitable for the characteristics of the display unit 106.
　なお、基本変換行列入力部１０８は、必ずしもユーザから入力を受け付ける必要はない。例えば、基本変換行列入力部１０８は、センサによって検知された色度であって表示部１０６に表示された色の色度に応じて自動的に設定された基本変換行列を入力として受け付けてもよい。 Note that the basic transformation matrix input unit 108 does not necessarily receive an input from the user. For example, the basic conversion matrix input unit 108 may accept as input the basic conversion matrix that is automatically set according to the chromaticity of the color that is detected by the sensor and displayed on the display unit 106. .
　変換部１０３は、後述する計算式を用いて、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを、１つの統合された変換処理で行うことにより、第２の画像信号を生成する。つまり、変換部１０３は、１回の変換処理で、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを同時に行う。具体的には、変換部１０３は、基本変換行列と第１のホワイトバランス係数とに基づいて、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行う。 The conversion unit 103 generates a second image signal by performing a white balance adjustment process and a color gamut conversion process on the first image signal by one integrated conversion process using a calculation formula described later. To do. That is, the conversion unit 103 performs the white balance adjustment process and the color gamut conversion process on the first image signal simultaneously in one conversion process. Specifically, the conversion unit 103 performs the white balance adjustment process and the color gamut conversion process for the first image signal based on the basic conversion matrix and the first white balance coefficient as one integrated conversion process. Do.
　本実施の形態では、変換部１０３は、係数算出部１０３ａと変換処理部１０３ｂとを備える。 In the present embodiment, the conversion unit 103 includes a coefficient calculation unit 103a and a conversion processing unit 103b.
　係数算出部１０３ａは、基本変換行列の逆行列と第１のホワイトバランス係数とを乗算することにより第２のホワイトバランス係数を算出する。具体的には、係数算出部１０３ａは、基本変換行列入力部１０８が受け付けた基本変換行列Ｐの逆行列Ｐ－１と、ホワイトバランス係数入力部１０７が受け付けた第１のホワイトバランス係数（α，β，γ）とを乗算することにより、第２のホワイトバランス係数（α’，β’，γ’）を算出する。なお、この係数算出部１０３ａの処理の詳細については、図３において詳細に説明する。 The coefficient calculation unit 103a calculates the second white balance coefficient by multiplying the inverse matrix of the basic conversion matrix by the first white balance coefficient. Specifically, the coefficient calculation unit 103a includes the inverse matrix P −1 of the basic conversion matrix P received by the basic conversion matrix input unit 108 and the first white balance coefficient (α, The second white balance coefficient (α ′, β ′, γ ′) is calculated by multiplying by β, γ). Details of the processing of the coefficient calculation unit 103a will be described in detail with reference to FIG.
　変換処理部１０３ｂは、算出された第２のホワイトバランス係数と基本変換行列とから得られる統合変換行列を用いて、第１の画像信号を第２の画像信号に変換する。つまり、変換処理部１０３ｂは、第２のホワイトバランス係数と基本変換行列とに基づいて生成される１つの統合変換行列を用いて第１の画像信号を第２の画像信号に変換する。なお、この変換処理部１０３ｂの処理の詳細については、図３において詳細に説明する。 The conversion processing unit 103b converts the first image signal into the second image signal using an integrated conversion matrix obtained from the calculated second white balance coefficient and the basic conversion matrix. That is, the conversion processing unit 103b converts the first image signal into the second image signal using one integrated conversion matrix generated based on the second white balance coefficient and the basic conversion matrix. Details of the processing of the conversion processing unit 103b will be described in detail with reference to FIG.
　このように生成された第２の画像信号は、ガンマ補正部１０４に出力される。 The second image signal generated in this way is output to the gamma correction unit 104.
　ガンマ補正部１０４は、予め定められた第２のガンマカーブに基づいて、第２の画像信号をガンマ補正する。つまり、ガンマ補正部１０４は、第２の画像信号に第２のガンマカーブをかける。このようにガンマ補正された画像信号は、第２の逆ガンマ補正部１０５に出力される。なお、第２のガンマカーブは、撮像装置２０におけるガンマ補正において用いられたガンマカーブと同一であることが好ましい。 The gamma correction unit 104 performs gamma correction on the second image signal based on a predetermined second gamma curve. That is, the gamma correction unit 104 applies the second gamma curve to the second image signal. The gamma-corrected image signal is output to the second inverse gamma correction unit 105. Note that the second gamma curve is preferably the same as the gamma curve used in the gamma correction in the imaging device 20.
　第２の逆ガンマ補正部１０５は、予め定められた第３のガンマカーブに基づいて、ガンマ補正部１０４によってガンマ補正された画像信号を逆ガンマ補正する。つまり、第２の逆ガンマ補正部１０５は、ガンマ補正部１０４から出力された画像信号からガンマカーブを取り除き、信号特性をリニアな状態にする。このように逆ガンマ補正された画像信号は、表示部１０６に出力される。 The second inverse gamma correction unit 105 performs inverse gamma correction on the image signal that has been gamma corrected by the gamma correction unit 104 based on a predetermined third gamma curve. In other words, the second inverse gamma correction unit 105 removes the gamma curve from the image signal output from the gamma correction unit 104 and makes the signal characteristics linear. The image signal subjected to inverse gamma correction in this way is output to the display unit 106.
　表示部１０６は、画像信号をディスプレイ等の画面に表示する。 The display unit 106 displays the image signal on a screen such as a display.
　次に、以上のように構成された画像変換装置１００の動作について説明する。 Next, the operation of the image conversion apparatus 100 configured as described above will be described.
　図３は、本発明の実施の形態１に係る画像変換装置１００の動作を示すフローチャートである。 FIG. 3 is a flowchart showing the operation of the image conversion apparatus 100 according to Embodiment 1 of the present invention.
　まず、取得部１１０は、第１の画像信号を取得する（Ｓ１０１）。具体的には、ステップＳ１０１において、ＲＧＢ変換部１０１は、入力画像信号の色空間をＹＵＶ色空間からＲＧＢ色空間に変換する（Ｓ１０１ａ）。続いて、第１の逆ガンマ補正部１０２は、予め定められた第１のガンマカーブに基づいて、ＲＧＢ変換部１０１によってＲＧＢ信号に変換された画像信号を逆ガンマ補正する（Ｓ１０１ｂ）。 First, the acquisition unit 110 acquires a first image signal (S101). Specifically, in step S101, the RGB conversion unit 101 converts the color space of the input image signal from the YUV color space to the RGB color space (S101a). Subsequently, the first inverse gamma correction unit 102 performs inverse gamma correction on the image signal converted into the RGB signal by the RGB conversion unit 101 based on a predetermined first gamma curve (S101b).
　次に、変換部１０３は、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行うことにより、第２の画像信号を生成する（Ｓ１０２）。 Next, the conversion unit 103 generates a second image signal by performing white balance adjustment processing and color gamut conversion processing on the first image signal by one integrated conversion processing (S102).
　具体的には、ステップＳ１０２において、係数算出部１０３ａは、（式４）に示すように、基本変換行列の逆行列Ｐ－１と第１のホワイトバランス係数（α，β，γ）とを乗算することにより第２のホワイトバランス係数（α’，β’，γ’）を算出する（Ｓ１０２ａ）。 Specifically, in step S102, the coefficient calculation unit 103a multiplies the inverse matrix P −1 of the basic transformation matrix and the first white balance coefficient (α, β, γ) as shown in (Equation 4). Thus, the second white balance coefficient (α ′, β ′, γ ′) is calculated (S102a).
Figure JPOXMLDOC01-appb-M000004
Figure JPOXMLDOC01-appb-M000004
　続いて、変換処理部１０３ｂは、（式５）に示すように、統合変換行列Ｐ’を用いて、第１の画像信号（ｒｉｎ，ｇｉｎ，ｂｉｎ）を第２の画像信号（ｒｏｕｔ，ｇｏｕｔ，ｂｏｕｔ）に変換する（Ｓ１０２ｂ）。 Subsequently, as shown in (Equation 5), the conversion processing unit 103b uses the integrated conversion matrix P ′ to convert the first image signal (r in , g in , b in ) into the second image signal (r out , g out , b out ) (S102b).
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　ここで、統合変換行列Ｐ’は、（式６）に示すように、第２のホワイトバランス係数（α’，β’，γ’）と基本変換行列Ｐとに基づいて生成される行列である。つまり、統合変換行列Ｐ’を用いることにより、ホワイトバランス調整処理及び色域変換処理を１つの変換処理で行うことができる。 Here, the integrated transformation matrix P ′ is a matrix generated based on the second white balance coefficients (α ′, β ′, γ ′) and the basic transformation matrix P as shown in (Equation 6). . That is, by using the integrated conversion matrix P ′, the white balance adjustment process and the color gamut conversion process can be performed by one conversion process.
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　このように、変換処理部１０３ｂは、第２のホワイトバランス係数と基本変換行列とに基づいて、第１の画像信号を第２の画像信号に変換する。 As described above, the conversion processing unit 103b converts the first image signal into the second image signal based on the second white balance coefficient and the basic conversion matrix.
　次に、ガンマ補正部１０４は、予め定められた第２のガンマカーブに基づいて、第２の画像信号をガンマ補正する（Ｓ１０３）。最後に、第２の逆ガンマ補正部１０５は、予め定められた第３のガンマカーブに基づいて、ガンマ補正部１０４によってガンマ補正された画像信号を逆ガンマ補正する（Ｓ１０４）。 Next, the gamma correction unit 104 performs gamma correction on the second image signal based on a predetermined second gamma curve (S103). Finally, the second inverse gamma correction unit 105 performs reverse gamma correction on the image signal that has been gamma corrected by the gamma correction unit 104 based on a predetermined third gamma curve (S104).
　このように、画像変換装置１００は、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行うことにより、第２の画像信号を生成する。 As described above, the image conversion apparatus 100 generates the second image signal by performing the white balance adjustment process and the color gamut conversion process on the first image signal by one integrated conversion process.
　ここで、第２のホワイトバランス係数について、さらに詳細に説明する。（式５）において、目的のホワイトバランスが実現されるためには、ｒｉｎ：ｇｉｎ：ｂｉｎ＝１：１：１のときに、ｒｏｕｔ：ｇｏｕｔ：ｂｏｕｔ＝α：β：γが満たされなければならない。つまり、第２のホワイトバランス係数（α’，β’，γ’）は、（式７）を満たさなければならない。 Here, the second white balance coefficient will be described in more detail. In (Expression 5), in order to achieve the target white balance, when r in : g in : b in = 1: 1: 1, r out : g out : b out = α: β: γ Must be satisfied. That is, the second white balance coefficient (α ′, β ′, γ ′) must satisfy (Equation 7).
Figure JPOXMLDOC01-appb-M000007
Figure JPOXMLDOC01-appb-M000007
　この（式７）を変形することにより、（式４）が導かれる。つまり、（式４）により算出された第２のホワイトバランス係数に基づいて変換処理が行われることにより、目的のホワイトバランスが実現される。この点について詳しく説明する。（式４）より第２のホワイトバランス係数（α’，β’，γ’）の成分には基本変換行列Ｐの逆行列が含まれる。よって、（式７）における計算過程でＰとＰ－１の乗算を行うことになる。結果として、ＰとＰ－１の乗算は単位行列となる。（式６）より統合変換行列Ｐ’は第１のホワイトバランス係数（α，β，γ）と等しくなる。つまり、（式５）の統合変換行列Ｐ’を第１のホワイトバランス係数（α，β，γ）で置き換えることが可能となる。結局のところ、第２の画像信号は第１のホワイトバランス係数（α，β，γ）の関数となり基本変換行列Ｐに依存しない。結論として、基本変換行列を調整しても、目的のホワイトバランスは変化しない。 By transforming (Equation 7), (Equation 4) is derived. That is, the target white balance is realized by performing the conversion process based on the second white balance coefficient calculated by (Equation 4). This point will be described in detail. From (Equation 4), the component of the second white balance coefficient (α ′, β ′, γ ′) includes an inverse matrix of the basic transformation matrix P. Accordingly, multiplication of P and P −1 is performed in the calculation process in (Equation 7). As a result, the multiplication of P and P −1 is a unit matrix. From (Equation 6), the integrated transformation matrix P ′ becomes equal to the first white balance coefficient (α, β, γ). That is, it is possible to replace the integrated transformation matrix P ′ in (Equation 5) with the first white balance coefficient (α, β, γ). After all, the second image signal is a function of the first white balance coefficient (α, β, γ) and does not depend on the basic transformation matrix P. In conclusion, adjusting the basic transformation matrix does not change the target white balance.
　また、（式５）において、第１の画像信号がＲ単色である場合（ｇｉｎ＝ｂｉｎ＝０）、第２の画像信号（ｒｏｕｔ，ｇｏｕｔ，ｂｏｕｔ）＝（α’ｐ１１ｇｉｎ，α’ｐ２１ｇｉｎ，α’ｐ３１ｇｉｎ）となる。つまり、この場合、第２のホワイトバランス係数（α’，β’，γ’）が変化しても、第２の画像信号におけるＲＧＢの比（ｒｏｕｔ：ｇｏｕｔ：ｂｏｕｔ）は変化しない。同様に、第１の画像信号がＧ単色又はＢ単色である場合も、第２の画像信号におけるＲＧＢの比（ｒｏｕｔ：ｇｏｕｔ：ｂｏｕｔ）は変化しない。つまり、（式５）において、第２の画像信号（ｒｏｕｔ，ｇｏｕｔ，ｂｏｕｔ）の色度は、第２のホワイトバランス係数（α’，β’，γ’）に依存しない。第２のホワイトバランス係数（α’，β’，γ’）は第１のホワイトバランス係数（α，β，γ）に基づいて定められる（式４）。よって、第２の画像信号（ｒｏｕｔ，ｇｏｕｔ，ｂｏｕｔ）の色度は第１のホワイトバランス係数（α，β，γ）に依存しない。つまり、第１のホワイトバランス係数を調整しても、第２の画像信号は変化しない。 In (Expression 5), when the first image signal is R monochromatic (g in = b in = 0), the second image signal (r out , g out , b out ) = (α′p 11 g in , α′p 21 g in , α′p 31 g in ). That is, in this case, even if the second white balance coefficient (α ′, β ′, γ ′) changes, the RGB ratio (r out : g out : b out ) in the second image signal does not change. Similarly, when the first image signal is a G single color or a B single color, the RGB ratio (r out : g out : b out ) in the second image signal does not change. That is, in (Equation 5), the chromaticity of the second image signal (r out , g out , b out ) does not depend on the second white balance coefficient (α ′, β ′, γ ′). The second white balance coefficient (α ′, β ′, γ ′) is determined based on the first white balance coefficient (α, β, γ) (Formula 4). Therefore, the chromaticity of the second image signal (r out , g out , b out ) does not depend on the first white balance coefficient (α, β, γ). In other words, even if the first white balance coefficient is adjusted, the second image signal does not change.
　次に、本実施の形態に係る画像変換装置による効果について、図４を用いて説明する。 Next, the effect of the image conversion apparatus according to the present embodiment will be described with reference to FIG.
　図４は、本発明の実施の形態１に係る画像変換装置１００の効果を説明するための図である。具体的には、図４の（ａ）は、従来の画像変換装置において第１のホワイトバランス係数を変化させたときに表示部に表示された画像の色度の計測結果を示す。また、図４の（ｂ）は、本実施の形態に係る画像変換装置１００において第１のホワイトバランス係数を変化させたときに表示部に表示された画像の色度の計測結果を示す。なお、基本変換行列は、すべての計測結果に対して変化させていない。 FIG. 4 is a diagram for explaining the effect of the image conversion apparatus 100 according to Embodiment 1 of the present invention. Specifically, FIG. 4A shows the measurement result of the chromaticity of the image displayed on the display unit when the first white balance coefficient is changed in the conventional image conversion apparatus. FIG. 4B shows the measurement result of the chromaticity of the image displayed on the display unit when the first white balance coefficient is changed in the image conversion apparatus 100 according to the present embodiment. Note that the basic transformation matrix is not changed for all measurement results.
　図４において、「Ｈｉｇｈ」、「Ｍｉｄ」、及び「Ｌｏｗ」は、第１のホワイトバランス係数に対応する。具体的には、「Ｈｉｇｈ」、「Ｍｉｄ」、及び「Ｌｏｗ」は、色温度が「１１５００Ｋ」、「９５００Ｋ」、及び「６５００Ｋ」となるように設定された第１のホワイトバランス係数である。 In FIG. 4, “High”, “Mid”, and “Low” correspond to the first white balance coefficient. Specifically, “High”, “Mid”, and “Low” are first white balance coefficients set so that the color temperatures are “11500K”, “9500K”, and “6500K”.
　また、図４には、ＲＧＢそれぞれの単色の画像信号に対してホワイトバランス調整処理及び色域変換処理を行ったときに計測された色度が示されている。例えば、色温度が１１５００Ｋを目的とする第１のホワイトバランス係数と基本変換行列とを用いて赤色単色の画像信号に対する変換処理を行った場合、従来の画像変換装置では色度（ｘ，ｙ）が（０．６４２，０．３３０）となることを示す。 FIG. 4 shows the chromaticity measured when the white balance adjustment process and the color gamut conversion process are performed on the RGB single-color image signals. For example, when conversion processing is performed on a red single-color image signal using the first white balance coefficient and the basic conversion matrix for a color temperature of 11500 K, the conventional image conversion apparatus uses chromaticity (x, y). Is (0.642, 0.330).
　また、色差ΔＥは、目的の色度と計測結果の色度との差異を表わすための値である。図４には、３つの第１のホワイトバランス係数に対応する色度のうち最も値が大きい色差ΔＥが示されている。 Further, the color difference ΔE is a value for representing the difference between the target chromaticity and the chromaticity of the measurement result. FIG. 4 shows the color difference ΔE having the largest value among the chromaticities corresponding to the three first white balance coefficients.
　図４から明らかなように、本実施の形態では、第１のホワイトバランス係数を変化させたときの色度の変化が従来よりも抑制されている。例えば、最大となる色差で比較した場合、従来の「２．６９６」に対し本実施の形態では「０．３０４」となっており、本実施の形態では、従来よりも約９倍も色度が安定している。 As is clear from FIG. 4, in this embodiment, the change in chromaticity when the first white balance coefficient is changed is suppressed more than in the past. For example, when compared with the maximum color difference, this embodiment is “0.304” compared to the conventional “2.696”, and in this embodiment, the chromaticity is about nine times that of the conventional one. Is stable.
　つまり、図４によれば、画像信号に対してホワイトバランス調整処理及び色域変換処理が行われる際に、本実施の形態に係る画像変換装置１００は、従来よりも、ホワイトバランス係数を変化させても表示部１０６に表示される画像の色度が変化しないように画像信号を変換することができる。 That is, according to FIG. 4, when the white balance adjustment process and the color gamut conversion process are performed on the image signal, the image conversion apparatus 100 according to the present embodiment changes the white balance coefficient more than before. However, the image signal can be converted so that the chromaticity of the image displayed on the display unit 106 does not change.
　以上のように、本実施の形態に係る画像変換装置１００によれば、第１の画像信号に対するホワイトバランス調整処理と色域変換処理とが１つの統合された変換処理で行うことができる。したがって、色域変換処理後に、画像信号のホワイトバランスが所望のホワイトバランスからずれてしまうことを防ぐことが可能となる。さらに、ホワイトバランス係数を変化させたときに表示部に表示される画像の色度の変化を抑制することも可能となる。 As described above, according to the image conversion apparatus 100 according to the present embodiment, the white balance adjustment process and the color gamut conversion process for the first image signal can be performed by one integrated conversion process. Therefore, it is possible to prevent the white balance of the image signal from deviating from the desired white balance after the color gamut conversion processing. Furthermore, it is possible to suppress a change in chromaticity of an image displayed on the display unit when the white balance coefficient is changed.
　また、本実施の形態に係る画像変換装置１００によれば、第１のホワイトバランス係数と基本変換行列の逆行列とを乗算することにより得られる第２のホワイトバランス係数と、基本変換行列とから得られる統合変換行列を用いて、第１の画像信号を第２の画像信号に変換することができる。つまり、ホワイトバランス調整処理と色域変換処理とが１つの統合された変換処理で行うことができるので、色域変換処理後に、画像信号のホワイトバランスが所望のホワイトバランスからずれてしまうことを防ぐことが可能となる。さらに、第２のホワイトバランス係数を用いて変換処理を行うことにより、第１のホワイトバランス係数を変化させたときに表示部に表示される画像の色度の変化を抑制することも可能となる。 Further, according to the image conversion apparatus 100 according to the present embodiment, the second white balance coefficient obtained by multiplying the first white balance coefficient and the inverse matrix of the basic conversion matrix, and the basic conversion matrix are used. The first image signal can be converted into the second image signal by using the obtained integrated conversion matrix. That is, since the white balance adjustment process and the color gamut conversion process can be performed by one integrated conversion process, the white balance of the image signal is prevented from deviating from a desired white balance after the color gamut conversion process. It becomes possible. Furthermore, by performing the conversion process using the second white balance coefficient, it is also possible to suppress a change in chromaticity of the image displayed on the display unit when the first white balance coefficient is changed. .
　また、本実施の形態に係る画像変換装置１００は、ＲＧＢ変換部１０１を備えるので、入力画像信号がＹＵＶ信号である場合にも、ホワイトバランス調整処理及び色域変換処理を行うことができる。さらに、画像変換装置１００では、ホワイトバランス調整処理及び色域変換処理が行われる前に逆ガンマ補正が行われる。したがって、リニアな信号特性を有する画像信号に対してホワイトバランス調整処理及び色域変換処理を高精度に行うことができ、表示部に表示される画像の色度の変化を抑制することも可能となる。 In addition, since the image conversion apparatus 100 according to the present embodiment includes the RGB conversion unit 101, white balance adjustment processing and color gamut conversion processing can be performed even when the input image signal is a YUV signal. Further, the image conversion apparatus 100 performs inverse gamma correction before the white balance adjustment process and the color gamut conversion process. Therefore, white balance adjustment processing and color gamut conversion processing can be performed with high accuracy on an image signal having linear signal characteristics, and a change in chromaticity of an image displayed on the display unit can be suppressed. Become.
　なお、本実施の形態において、入力画像信号は、ガンマ補正されたＹＵＶ信号であったが、必ずしもこのような信号である必要はない。例えば、入力画像信号は、ガンマ補正されていないＲＧＢ信号であってもよい。この場合、取得部１１０は、ＲＧＢ変換部１０１と第１の逆ガンマ補正部１０２とを備える必要はない。つまり、取得部１１０は、入力画像信号を第１の画像信号として取得すればよい。さらに、画像変換装置１００は、ガンマ補正部１０４及び第２の逆ガンマ補正部１０５を備える必要もない。つまり、画像変換装置１００は、第２の画像信号を出力画像信号として表示部１０６に出力すればよい。 In the present embodiment, the input image signal is a gamma-corrected YUV signal, but it is not necessarily such a signal. For example, the input image signal may be an RGB signal that has not been gamma corrected. In this case, the acquisition unit 110 does not need to include the RGB conversion unit 101 and the first inverse gamma correction unit 102. That is, the acquisition unit 110 may acquire the input image signal as the first image signal. Further, the image conversion apparatus 100 does not need to include the gamma correction unit 104 and the second inverse gamma correction unit 105. That is, the image conversion apparatus 100 may output the second image signal to the display unit 106 as an output image signal.
　（実施の形態２）
　次に、本発明の実施の形態２について説明する。 (Embodiment 2)
Next, a second embodiment of the present invention will be described.
　図５は、本発明の実施の形態２に係る画像変換システムの機能構成を示すブロック図である。なお、図５において、図２と同様の構成部については、同一の符号を付し、適宜説明を省略する。 FIG. 5 is a block diagram showing a functional configuration of the image conversion system according to the second embodiment of the present invention. In FIG. 5, the same components as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
　画像変換装置１５０は、図２に示す各構成部に加えて、ガンマカーブ選択部１５１とガンマカーブ調整部１５２とを備える。 The image conversion apparatus 150 includes a gamma curve selection unit 151 and a gamma curve adjustment unit 152 in addition to the components shown in FIG.
　ガンマカーブ選択部１５１は、予め保持されている複数のガンマカーブの中からガンマカーブを選択する。具体的には、ガンマカーブ選択部１５１は、例えば、入力手段（図示せず）によって受け付けられたユーザからの入力に基づいて、ガンマカーブを選択する。また例えば、ガンマカーブ選択部１５１は、入力画像信号を解析して、当該入力画像信号に適応するガンマカーブを選択してもよい。 The gamma curve selection unit 151 selects a gamma curve from a plurality of gamma curves held in advance. Specifically, the gamma curve selection unit 151 selects a gamma curve based on an input from a user received by an input unit (not shown), for example. Further, for example, the gamma curve selection unit 151 may analyze the input image signal and select a gamma curve adapted to the input image signal.
　ガンマカーブ調整部１５２は、選択されたガンマカーブの一部を調整する。具体的には、ガンマカーブ調整部１５２は、例えば、入力手段によって受け付けられたユーザからの入力に基づいて、ガンマカーブの一部を微調整する。また例えば、ガンマカーブ調整部１５２は、入力画像信号を解析して、当該入力画像信号に適応するように、ガンマカーブの一部を調整してもよい。 The gamma curve adjustment unit 152 adjusts a part of the selected gamma curve. Specifically, the gamma curve adjustment unit 152 finely adjusts a part of the gamma curve based on the input from the user received by the input unit, for example. For example, the gamma curve adjustment unit 152 may analyze the input image signal and adjust a part of the gamma curve so as to adapt to the input image signal.
　第１の逆ガンマ補正部１０２、ガンマ補正部１０４および第２の逆ガンマ補正部１０５のうちの少なくとも１つは、ガンマカーブ調整部１５２によって調整されたガンマカーブに基づいてガンマ補正又は逆ガンマ補正を行う。 At least one of the first inverse gamma correction unit 102, the gamma correction unit 104, and the second reverse gamma correction unit 105 performs gamma correction or reverse gamma correction based on the gamma curve adjusted by the gamma curve adjustment unit 152. I do.
　図６は、本発明の実施の形態２に係る画像変換装置１５０におけるガンマカーブ調整の一例を説明するための図である。図６において、横軸は入力レベル、縦軸は出力レベルを表している。 FIG. 6 is a diagram for explaining an example of gamma curve adjustment in the image conversion apparatus 150 according to Embodiment 2 of the present invention. In FIG. 6, the horizontal axis represents the input level, and the vertical axis represents the output level.
　ガンマカーブ３０１は、入力レベルに対して１６分割されている。そして、ユーザは、各分割部分を代表する分割点３０２を、調整可能範囲３０３内において上下に調整することができる。 The gamma curve 301 is divided into 16 with respect to the input level. Then, the user can adjust the dividing point 302 representing each divided portion up and down within the adjustable range 303.
　調整可能範囲３０３は、入力レベル及び出力レベルの上限値が１０２４である場合、調整前の分割点３０２の位置を中心とした±１２８の範囲とする。ただし、調整可能範囲３０３は、０を下限とし、１０２４を上限とする。 The adjustable range 303 is a range of ± 128 around the position of the division point 302 before adjustment when the upper limit value of the input level and output level is 1024. However, the adjustable range 303 has 0 as a lower limit and 1024 as an upper limit.
　このように、本実施の形態に係る画像変換装置１５０によれば、ガンマ補正又は逆ガンマ補正に用いるガンマカーブをユーザが調整することが可能となり、ディーラーキャリブレーションに対応することが可能となる。 As described above, according to the image conversion apparatus 150 according to the present embodiment, the user can adjust the gamma curve used for gamma correction or inverse gamma correction, and it is possible to deal with dealer calibration.
　以上、本発明の一態様に係る画像変換装置１００について、実施の形態に基づいて説明したが、本発明は、これらの実施の形態に限定されるものではない。本発明の趣旨を逸脱しない限り、当業者が思いつく各種変形を本実施の形態に施したもの、あるいは異なる実施の形態における構成要素を組み合わせて構築される形態も、本発明の範囲内に含まれる。 As described above, the image conversion apparatus 100 according to one aspect of the present invention has been described based on the embodiments. However, the present invention is not limited to these embodiments. Unless it deviates from the meaning of this invention, the form which carried out various deformation | transformation which those skilled in the art can think to this embodiment, or the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .
　例えば、上記実施の形態１及び２において、画像変換装置１００、１５０は、表示装置１０に備えられていたが、必ずしも表示装置１０に備えられる必要ない。例えば、表示部を備えていないＢＤプレーヤあるいはセットトップボックスなどが、画像変換装置１００、１５０を備えてもよい。 For example, in the first and second embodiments, the image conversion apparatuses 100 and 150 are included in the display apparatus 10, but are not necessarily included in the display apparatus 10. For example, a BD player or a set top box that does not include a display unit may include the image conversion apparatuses 100 and 150.
　また、上記実施の形態１及び２において、入力画像信号は、撮像装置２０によって生成された画像信号であったが、必ずしも入力画像信号は、撮像装置２０によって生成される必要はない。例えば、入力画像信号は、コンピュータによって生成された画像信号（いわゆるＣＧ（Ｃｏｍｐｕｔｅｒ　Ｇｒａｐｈｉｃｓ））であってもよい。 In Embodiments 1 and 2, the input image signal is an image signal generated by the imaging device 20, but the input image signal does not necessarily have to be generated by the imaging device 20. For example, the input image signal may be an image signal generated by a computer (so-called CG (Computer Graphics)).
　また、上記実施の形態１または２における画像変換装置１００が備える構成要素の一部または全部は、１個のシステムＬＳＩ（Ｌａｒｇｅ　Ｓｃａｌｅ　Ｉｎｔｅｇｒａｔｉｏｎ：大規模集積回路）から構成されているとしてもよい。例えば、画像変換装置１００は、取得部１１０と変換部１０３とを有するシステムＬＳＩから構成されてもよい。 Further, some or all of the constituent elements included in the image conversion apparatus 100 according to the first or second embodiment may be configured by one system LSI (Large Scale Integration). For example, the image conversion apparatus 100 may be configured by a system LSI having an acquisition unit 110 and a conversion unit 103.
　システムＬＳＩは、複数の構成部を１個のチップ上に集積して製造された超多機能ＬＳＩであり、具体的には、マイクロプロセッサ、ＲＯＭ（Ｒｅａｄ　Ｏｎｌｙ　Ｍｅｍｏｒｙ）、ＲＡＭ（Ｒａｍｄｏｍ　Ａｃｃｅｓｓ　Ｍｅｍｏｒｙ）などを含んで構成されるコンピュータシステムである。ＲＯＭには、コンピュータプログラムが記憶されている。マイクロプロセッサが、コンピュータプログラムに従って動作することにより、システムＬＳＩは、その機能を達成する。 The system LSI is an ultra-multifunctional LSI manufactured by integrating a plurality of components on a single chip. Specifically, a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), etc. It is a computer system comprised including. A computer program is stored in the ROM. The system LSI achieves its functions by the microprocessor operating according to the computer program.
　なお、ここでは、システムＬＳＩとしたが、集積度の違いにより、ＩＣ、ＬＳＩ、スーパーＬＳＩ、ウルトラＬＳＩと呼称されることもある。また、集積回路化の手法はＬＳＩに限るものではなく、専用回路又は汎用プロセッサで実現してもよい。ＬＳＩ製造後に、プログラムすることが可能なＦＰＧＡ（Ｆｉｅｌｄ　Ｐｒｏｇｒａｍｍａｂｌｅ　Ｇａｔｅ　Ａｒｒａｙ）、あるいはＬＳＩ内部の回路セルの接続や設定を再構成可能なリコンフィギュラブル・プロセッサを利用してもよい。 Note that although the system LSI is used here, it may be called IC, LSI, super LSI, or ultra LSI depending on the degree of integration. Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI, or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
　さらには、半導体技術の進歩又は派生する別技術によりＬＳＩに置き換わる集積回路化の技術が登場すれば、当然、その技術を用いて機能ブロックの集積化を行ってもよい。バイオ技術の適用等が可能性としてありえる。 Furthermore, if integrated circuit technology that replaces LSI emerges as a result of advances in semiconductor technology or other derived technology, it is naturally also possible to integrate functional blocks using this technology. Biotechnology can be applied.
　また、本発明は、このような特徴的な処理部を備える画像変換装置として実現することができるだけでなく、画像変換装置に含まれる特徴的な処理部をステップとする画像変換方法として実現することもできる。また、画像変換方法に含まれる特徴的な各ステップをコンピュータに実行させるコンピュータプログラムとして実現することもできる。そして、そのようなコンピュータプログラムを、ＣＤ－ＲＯＭ等のコンピュータ読取可能な非一時的な記録媒体あるいはインターネット等の通信ネットワークを介して流通させることができるのは、言うまでもない。 Further, the present invention can be realized not only as an image conversion apparatus including such a characteristic processing unit, but also as an image conversion method using the characteristic processing unit included in the image conversion apparatus as a step. You can also. It can also be realized as a computer program that causes a computer to execute the characteristic steps included in the image conversion method. Needless to say, such a computer program can be distributed via a computer-readable non-transitory recording medium such as a CD-ROM or a communication network such as the Internet.
　本発明の一態様に係る画像変換装置は、ホワイトバランス調整及び色域変換を容易に実現でき、画像を出力可能なあらゆるＡＶ機器に利用することができる。 The image conversion apparatus according to an aspect of the present invention can easily realize white balance adjustment and color gamut conversion, and can be used for any AV device that can output an image.
　１０　　表示装置
　２０　　撮像装置
　１００、１５０　　画像変換装置
　１０１　　ＲＧＢ変換部
　１０２　　第１の逆ガンマ補正部
　１０３　　変換部
　１０３ａ　係数算出部
　１０３ｂ　変換処理部
　１０４、２０２　　ガンマ補正部
　１０５　　第２の逆ガンマ補正部
　１０６　　表示部
　１０７　　ホワイトバランス係数入力部
　１０８　　基本変換行列入力部
  １１０　　取得部
　１５１　　ガンマカーブ選択部
　１５２　　ガンマカーブ調整部
　２０１　　撮像部
　２０３　　ＹＵＶ変換部 DESCRIPTION OF SYMBOLS 10 Display apparatus 20 Imaging apparatus 100,150 Image conversion apparatus 101 RGB conversion part 102 1st reverse gamma correction part 103 Conversion part 103a Coefficient calculation part 103b Conversion process part 104,202 Gamma correction part 105 2nd reverse gamma correction part 106 Display unit 107 White balance coefficient input unit 108 Basic conversion matrix input unit 110 Acquisition unit 151 Gamma curve selection unit 152 Gamma curve adjustment unit 201 Imaging unit 203 YUV conversion unit

Claims (9)

  1. 　画像信号に対してホワイトバランス調整処理及び色域変換処理を行う画像変換装置であって、
    　第１の画像信号を取得する取得部と、
    　取得された前記第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行うことにより、第２の画像信号を生成する変換部とを備える
    　画像変換装置。     An image conversion apparatus that performs white balance adjustment processing and color gamut conversion processing on an image signal,
    An acquisition unit for acquiring a first image signal;
    An image conversion apparatus comprising: a conversion unit that generates a second image signal by performing a white balance adjustment process and a color gamut conversion process on the acquired first image signal by one integrated conversion process.
  2. 　前記変換部は、前記第１の画像信号の色域を目的の色域に変換するための基本変換行列と、目的となるホワイトバランスを示す第１のホワイトバランス係数とに基づいて、前記１つの統合された変換処理を行う
    　請求項１に記載の画像変換装置。     The conversion unit is configured to convert the one image signal based on a basic conversion matrix for converting a color gamut of the first image signal into a target color gamut and a first white balance coefficient indicating a target white balance. The image conversion apparatus according to claim 1, wherein integrated conversion processing is performed.
  3. 　前記変換部は、
    　前記第１のホワイトバランス係数と前記基本変換行列の逆行列とを乗算することにより第２のホワイトバランス係数を算出する係数算出部と、
    　算出された前記第２のホワイトバランス係数と前記基本変換行列とに基づいて、前記第１の画像信号を前記第２の画像信号に変換する変換処理部とを備える
    　請求項２に記載の画像変換装置。     The converter is
    A coefficient calculation unit for calculating a second white balance coefficient by multiplying the first white balance coefficient by an inverse matrix of the basic transformation matrix;
    The image conversion according to claim 2, further comprising: a conversion processing unit that converts the first image signal into the second image signal based on the calculated second white balance coefficient and the basic conversion matrix. apparatus.
  4. 　前記取得部は、
    　入力画像信号の色空間をＹＵＶ色空間からＲＧＢ色空間に変換するＲＧＢ変換部と、
    　予め定められた第１のガンマカーブに基づいて、前記ＲＧＢ変換部によってＲＧＢ色空間に変換された入力画像信号の逆ガンマ補正を行うことにより、前記第１の画像信号を取得する第１の逆ガンマ補正部とを備える
    　請求項１～３のいずれか１項に記載の画像変換装置。     The acquisition unit
    An RGB converter that converts a color space of an input image signal from a YUV color space to an RGB color space;
    Based on a predetermined first gamma curve, a first inverse of obtaining the first image signal by performing inverse gamma correction of the input image signal converted into the RGB color space by the RGB converter. The image conversion apparatus according to claim 1, further comprising a gamma correction unit.
  5. 　さらに、
    　予め定められた第２のガンマカーブに基づいて、前記第２の画像信号のガンマ補正を行うガンマ補正部と、
    　予め定められた第３のガンマカーブに基づいて、前記ガンマ補正部によってガンマ補正された第２の画像信号の逆ガンマ補正を行う第２の逆ガンマ補正部とを備える
    　請求項４に記載の画像変換装置。     further,
    A gamma correction unit that performs gamma correction of the second image signal based on a predetermined second gamma curve;
    5. The image according to claim 4, further comprising: a second inverse gamma correction unit that performs reverse gamma correction of the second image signal that has been gamma corrected by the gamma correction unit based on a predetermined third gamma curve. Conversion device.
  6. 　さらに、
    　予め保持された複数のガンマカーブの中からカンマカーブを選択するガンマカーブ選択部と、
    　選択された前記ガンマカーブの一部を調整するガンマカーブ調整部とを備え、
    　前記第１の逆ガンマ補正部、前記ガンマ補正部、及び前記第２の逆ガンマ補正部のうちの少なくとも１つは、前記ガンマカーブ調整部によって調整されたガンマカーブに基づいて、前記ガンマ補正又は前記逆ガンマ補正を行う
    　請求項５に記載の画像変換装置。     further,
    A gamma curve selection unit for selecting a comma curve from a plurality of gamma curves held in advance;
    A gamma curve adjusting unit for adjusting a part of the selected gamma curve,
    At least one of the first inverse gamma correction unit, the gamma correction unit, and the second reverse gamma correction unit is based on the gamma curve adjusted by the gamma curve adjustment unit, or the gamma correction or The image conversion apparatus according to claim 5, wherein the inverse gamma correction is performed.
  7. 　前記画像変換装置は、集積回路として構成されている
    　請求項１～６のいずれか１項に記載の画像変換装置。     The image conversion apparatus according to any one of claims 1 to 6, wherein the image conversion apparatus is configured as an integrated circuit.
  8. 　画像信号に対してホワイトバランス調整処理及び色域変換処理を行う画像変換方法であって、
    　第１の画像信号を取得する取得ステップと、
    　取得された前記第１の画像信号に対するホワイトバランス調整処理と色域変換処理とを１つの統合された変換処理で行うことにより、第２の画像信号を生成する変換ステップとを含む
    　画像変換方法。     An image conversion method for performing white balance adjustment processing and color gamut conversion processing on an image signal,
    An acquisition step of acquiring a first image signal;
    A conversion step of generating a second image signal by performing a white balance adjustment process and a color gamut conversion process on the acquired first image signal by one integrated conversion process.
  9. 　請求項８に記載の画像変換方法をコンピュータに実行させるためのプログラム。 A program for causing a computer to execute the image conversion method according to claim 8.
PCT/JP2011/002469 2010-04-28 2011-04-27 Image conversion device and image conversion method WO2011135855A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2010-103297 2010-04-28
JP2010103297A JP2013145931A (en) 2010-04-28 2010-04-28 Image conversion apparatus

Publications (1)

Publication Number Publication Date
WO2011135855A1 true WO2011135855A1 (en) 2011-11-03

Family

ID=44861177

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2011/002469 WO2011135855A1 (en) 2010-04-28 2011-04-27 Image conversion device and image conversion method

Country Status (2)

Country Link
JP (1) JP2013145931A (en)
WO (1) WO2011135855A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015154307A (en) * 2014-02-17 2015-08-24 ソニー株式会社 Image processing system, image processing method, and program

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002232905A (en) * 2001-01-30 2002-08-16 Sony Corp Chromaticity transformation device and chromaticity transformation method, display device and display method, recording medium, and program
JP2008304758A (en) * 2007-06-08 2008-12-18 Pioneer Electronic Corp Image processor and image processing method
JP2009111823A (en) * 2007-10-31 2009-05-21 Sharp Corp Video signal conversion apparatus, video display device, and video signal conversion method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002232905A (en) * 2001-01-30 2002-08-16 Sony Corp Chromaticity transformation device and chromaticity transformation method, display device and display method, recording medium, and program
JP2008304758A (en) * 2007-06-08 2008-12-18 Pioneer Electronic Corp Image processor and image processing method
JP2009111823A (en) * 2007-10-31 2009-05-21 Sharp Corp Video signal conversion apparatus, video display device, and video signal conversion method

Also Published As

Publication number Publication date
JP2013145931A (en) 2013-07-25

Similar Documents

Publication Publication Date Title
KR100710302B1 (en) Apparatus and method for compensating color of video signal in a display device
US8497872B2 (en) White balance correction method
US8098932B2 (en) Color correction method and apparatus of display apparatus
JP2006129456A (en) Correction data setting method and manufacturing method of image display apparatus
US20110148907A1 (en) Method and system for image display with uniformity compensation
JP2007129622A (en) Imaging apparatus, image processor, image processing method, and image processing program
JP2003199117A (en) Image pickup device and signal processing method for solid-state imaging element
JP2009237088A (en) Correction method, display device and computer program
JP6351202B2 (en) Method for viewing simulated light output and apparatus for generating simulated light output
CN111091789B (en) Display device and color correction method thereof
JP6520578B2 (en) Image processing apparatus and display determination method
JP6779695B2 (en) Image processing device and its control method, display device
JP2007114427A (en) Display and its adjusting method
CN104980650A (en) F-stop weighted waveform with picture monitor markers
JP2008166892A (en) Data processor, image signal processor and method, and computer program
JP2010217645A (en) Method, device and program of making correction value of image display device
TWI697872B (en) Color difference adjusted image data generating method, color difference adjusted image displaying method, color difference adjusted image data generating device, and color difference adjusted image display system
US10754149B2 (en) Efficient radial lens shading correction
JP4832900B2 (en) Image output apparatus, image output method, and computer program
JP2014109710A (en) Method for manufacturing display device
JP5227539B2 (en) Output value setting method, output value setting device, and display device
WO2011135855A1 (en) Image conversion device and image conversion method
JP2010217644A (en) Method, device and program of making correction value of image display device
US9723283B2 (en) Image processing device, image processing system, and image processing method
JP5504188B2 (en) Measurement system, display device, measurement device, correction device, and measurement method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 11774641

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 11774641

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: JP