JP2005184137A - Digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a digital camera having satisfactory reproducibility of color. <P>SOLUTION: The digital camera comprises cameras 1, 2; a memory 8 for storing a first UV signal from the camera 1; a calculation section 9 for calculating characteristics regarding color correction in the camera 2, based on the first UV signal stored in the memory 8 and a second UV signal from the camera 2; and a correction section 11 for correcting the second UV signal, based on the characteristics regarding the color correction calculated by the calculation section 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital camera having two or more cameras in a portable terminal or the like.

  FIG. 6 is a block circuit diagram showing a configuration of a conventional digital camera 90. The digital camera 90 includes a camera 1 and a camera 2. The camera 1 has a CMOS sensor 101 as an image sensor, a CDS unit 102, an AGC unit 103, and an AD conversion unit 104, and outputs RGB digital signals to the switch 3. The color filter array of the CMOS sensor 101 is a primary color Bayer array C90 shown in FIG.

  Similar to the camera 1, the camera 2 includes a CMOS sensor 201 as an image sensor, a CDS unit 202, an AGC unit 203, and an AD conversion unit 204, and outputs RGB digital signals to the switch 3. The color filter array of the CMOS sensor 201 is a primary color Bayer array C90 shown in FIG.

  The switch 3 exclusively outputs either the RGB digital signal from the camera 1 or the RGB digital signal from the camera 2 to the Y signal processing unit 94, the C signal processing unit 95, and the white balance adjustment unit 6.

  FIG. 8 is a block circuit diagram showing a configuration of the Y signal processing unit 94. In the RGB-Y conversion unit 401, the Y signal processing unit 94 converts the RGB signal into the Y signal Y1 by the following (Equation 1).

_{Y1 = a 11 R + a 12} G + a 13 B ( Equation 1)
Next, the offset value Y _off is added to the signal Y1 by the following (Equation 2) in the offset adjustment unit 402, and the signal Y2 is output.

Y2 = Y1 + Y _off (Formula 2)
Next, the signal Y2 is multiplied by the gain Ky by the following (Equation 3) in the gain adjusting unit 403, and the signal Y is output.

Y = Ky × Y2 (Formula 3)
Similarly, the operation of the C signal processing unit 95 will be described with reference to FIG. FIG. 9 is a block circuit diagram showing a configuration of the C signal processing unit 95. In the RGB-UV conversion unit 501, the C signal processing unit 5 converts the RGB signal into the U signal U1 and the V signal V1 by the following (Equation 4).

U1 = a ₂₁ R + a ₂₂ G + a ₂₃ B
V1 = a ₃₁ R + a ₃₂ G + a ₃₃ B (Formula 4)
Next, the U signal U1 and the V signal V1 are converted into the signal U2 and the signal V2 by the following (Equation 5) in the matrix section 502.

_{U2 = b 11 U1 + b 12} V1
V2 = b ₂₁ U1 + b ₂₂ V1 (Formula 5)
Next, the signal U2 and the signal V2 are converted into the signal U3 and the signal V3, respectively, by adding the U offset value U _off and the V offset value V _off by the following (Equation 6) in the offset adjustment unit 503.

U3 = U2 + U _off
V3 = V2 + _Voff (Formula 6)
Next, the signal U3 and the signal V3 are multiplied by the U gain Ku and the V gain Kv by the following (Equation 7) in the gain adjusting unit 504, and converted into the signal U and the signal V.

U = Ku × U3
V = Kv × V3 (Formula 7)
Next, the operation of the white balance adjustment unit 6 will be described. The white balance adjustment unit 6 is controlled so that the values of R, G, and B are equal when a white signal is input. Specifically, when the input signal of the white balance adjustment unit 6 is R, G, and B, the variable conversion shown in the following (Equation 8) is performed, and the coefficient Kr, such that R ′ = G = B ′, Kb is obtained for each color temperature.

R ′ = Kr × R
B ′ = Kb × B (Formula 8)
The obtained coefficients Kr and Kb are fed back to the RGB-Y conversion unit 401 and the RGB-UV conversion unit 501, and are multiplied by the R signal and B signal before YUV conversion.

Thus, the parameters Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , determined by (Equation 2), (Equation 3), (Equation 5), (Equation 6) and (Equation 7), b ₁₂ , b ₂₁ and b ₂₂ are stored in the memory 8, and the control unit 97 performs read and write operations to the memory 8 and control operations to the Y signal processing unit 94 and the C signal processing unit 95.
JP 2001-339734 A Japanese Patent Laid-Open No. 10-285610 JP-A-6-292224

  Incidentally, imaging devices such as CCDs and CMOSs generally have different spectral characteristics. Therefore, when the first camera 1 and the second camera 2 are imaged without adjustment, the color reproducibility of the two may be different from each other.

As a means for solving this problem, a standard color chart is imaged using the first camera 1 and the second camera 2, and the parameters Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , b _{12 are} recorded. , B ₂₁ and b ₂₂ may be individually set for each of the first camera 1 and the second camera 2. As the standard color chart, a Macbeth color chart or the like is used.

  However, such adjustment work is very complicated, and it has been difficult to adjust the color reproduction of the first camera 1 and the second camera 2 because the skill level of the operator is required.

  An object of the present invention is to provide a digital camera having good color reproducibility.

  The digital camera according to the present invention is a digital camera comprising first and second cameras and a memory for storing a first UV signal from the first camera, and the first UV signal stored in the memory and the first camera. A calculation unit that calculates characteristics related to color correction of the second camera based on the second UV signals from the two cameras; and a second calculation unit that calculates the characteristics of the second UV signal based on the characteristics related to color correction calculated by the calculation unit. And a correction unit that determines a parameter for color correction.

  ADVANTAGE OF THE INVENTION According to this invention, the digital camera which has favorable color reproducibility can be provided.

  In the digital camera according to the present embodiment, based on the first UV signal stored in the memory and the second UV signal from the second camera, a calculation unit that calculates characteristics relating to color correction of the second camera, And a correction unit that determines a parameter for color correction of the second UV signal based on the color correction characteristic calculated by the unit. For this reason, the color characteristics of the second camera can be easily matched with the color characteristics of the first camera without requiring complicated adjustment work and skill level of the operator. As a result, it is possible to easily obtain a digital camera in which the color reproducibility of the first camera and the color reproducibility of the second camera are equal to each other.

  In this embodiment, it is preferable that the first and second cameras output RGB digital signals, respectively.

  It is preferable to further include a switch for exclusively outputting either the RGB digital signal from the first camera or the RGB digital signal from the second camera.

  It is preferable to further include a Y signal processing unit that generates a Y signal based on the RGB digital signal output from the switch.

  It is preferable that the image processing apparatus further includes a C signal processing unit that generates either the first UV signal or the second UV signal based on the RGB digital signal output from the switch.

  It is preferable to further include a white balance adjustment unit that calculates a white balance coefficient based on the RGB digital signal output from the switch.

  A first Y signal processing unit that generates a first Y signal based on the RGB digital signal output from the first camera, and a second Y signal that generates a second Y signal based on the RGB digital signal output from the second camera. Two Y signal processing units, a first C signal processing unit that generates the first UV signal based on RGB digital signals output from the first camera, and an RGB digital signal output from the second camera. And a second C signal processing unit that generates the second UV signal based on the second C signal processing unit, and a switch that exclusively outputs the first Y signal, the first UV signal, the second Y signal, and the second UV signal. It is preferable to provide.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block circuit diagram showing a configuration of a digital camera 100 according to the first embodiment. The digital camera 100 includes a camera 1 and a camera 2. The camera 1 has a CMOS sensor 101 as an image sensor, a CDS unit 102, an AGC unit 103, and an AD conversion unit 104, and outputs RGB digital signals to the switch 3. The color filter array of the CMOS sensor 101 is a primary color Bayer array C1 shown in FIG.

  Similar to the camera 1, the camera 2 includes a CMOS sensor 201 as an image sensor, a CDS unit 202, an AGC unit 203, and an AD conversion unit 204, and outputs RGB digital signals to the switch 3. The color filter array of the CMOS sensor 201 is a primary color Bayer array C1 shown in FIG.

  The switch 3 exclusively outputs one of the RGB digital signal from the camera 1 and the RGB digital signal from the camera 2 to the Y signal processing unit 4, the C signal processing unit 5, and the white balance adjustment unit 6.

  FIG. 3 is a block circuit diagram showing a configuration of the Y signal processing unit 4. In the RGB-Y conversion unit 401, the Y signal processing unit 4 converts the RGB signal into the Y signal Y1 by the following (Equation 1).

_{Y1 = a 11 R + a 12} G + a 13 B ( Equation 1)
Next, the offset value Y _off is added to the signal Y1 by the following (Equation 2) in the offset adjustment unit 402, and the signal Y2 is output.

Y2 = Y1 + Y _off (Formula 2)
Next, the signal Y2 is multiplied by the gain Ky by the following (Equation 3) in the gain adjusting unit 403, and the signal Y is output.

Y = Ky × Y2 (Formula 3)
Similarly, the operation of the C signal processing unit 5 will be described with reference to FIG. FIG. 4 is a block circuit diagram showing a configuration of the C signal processing unit 5. In the RGB-UV conversion unit 501, the C signal processing unit 5 converts the RGB signal into the U signal U1 and the V signal V1 by the following (Equation 4).

U1 = a ₂₁ R + a ₂₂ G + a ₂₃ B
V1 = a ₃₁ R + a ₃₂ G + a ₃₃ B (Formula 4)
Next, the U signal U1 and the V signal V1 are converted into the signal U2 and the signal V2 by the following (Equation 5) in the matrix section 502.

_{U2 = b 11 U1 + b 12} V1
V2 = b ₂₁ U1 + b ₂₂ V1 (Formula 5)
Next, the signal U2 and the signal V2 are converted into the signal U3 and the signal V3, respectively, by adding the U offset value U _off and the V offset value V _off by the following (Equation 6) in the offset adjustment unit 503.

U3 = U2 + U _off
V3 = V2 + _Voff (Formula 6)
Next, the signal U3 and the signal V3 are multiplied by the U gain Ku and the V gain Kv by the following (Equation 7) in the gain adjusting unit 504, and converted into the signal U and the signal V.

U = Ku × U3
V = Kv × V3 (Formula 7)
Next, the operation of the white balance adjustment unit 6 will be described. The white balance adjustment unit 6 is controlled so that the values of R, G, and B are equal when a white signal is input. Specifically, when the input signal of the white balance adjustment unit 6 is R, G, and B, the variable conversion shown in the following (Equation 8) is performed, and the coefficient Kr, such that R ′ = G = B ′, Kb is obtained for each color temperature.

R ′ = Kr × R
B ′ = Kb × B (Formula 8)
The obtained coefficients Kr and Kb are fed back to the RGB-Y conversion unit 401 and the RGB-UV conversion unit 501, and are multiplied by the R signal and B signal before YUV conversion.

Thus, Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , b determined by (Equation 2), (Equation 3), (Equation 5), (Equation 6) and (Equation 7). ₁₂ , b ₂₁ and b ₂₂ are stored in the memory 8, and the control unit 7 performs read and write operations on the memory 8 and control operations on the Y signal processing unit 4 and the C signal processing unit 5.

Next, a method of adjusting the color reproduction between the first camera 1 and the second camera 2 using a standard color chart will be described. Color matching is performed using N colors of the standard color chart. For the first camera 1, the parameters Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , b ₁₂ , b _21, and b ₂₂ for setting color reproducibility are acquired in advance. Yes, and stored in the memory 8.

  First, the UV values of the first color of the standard color chart imaged by the first camera 1 are U (1,1) and V (1,1), respectively, and the UV values of the second color are U (1 , 2), V (1, 2), and the UV value of the Nth color is U (1, N), V (1, N). Then, N U values from U (1,1) to U (1, N) and N V values from V (1,1) to V (1, N) are stored in the memory 10. To do.

  Next, a method for adjusting the second camera 2 will be described. The UV values of the first color of the standard color chart imaged by the second camera 2 are U (2,1) and V (2,1), respectively, and the UV values of the second color are U (2,2), respectively. ), V (2, 2), and the UV values of the Nth color are U (2, N) and V (2, N). Then, N U values from U (2,1) to U (2, N) and N V values from V (2,1) to V (2, N) are stored in the memory 10. To do.

  In the calculation unit 9, for the Nth color in the standard color chart, the square of the difference between the UV value of the first camera and the UV value of the second camera is Δ (N), and Perform the calculation as determined.

Δ (N) = (U (1, N) −U (2, N)) ² + (V (1, N) −V (2, N)) ² (Equation 9)
Further, assuming that the sum of Δ (N) from 1 to N is A, the calculation defined in (Equation 10) below is performed.

A = Δ (1) + Δ (2) +... + Δ (N) (Formula 10)
In the correction unit 11, the parameters Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , color correction for the second camera 2 are set so that the value of A in (Expression 10) becomes small. b ₁₂ , b ₂₁ and b ₂₂ are appropriately changed, and the changed parameters are supplied to the Y signal processing unit 4 and the C signal processing unit 5 through the control unit 7. In this way, color matching between the first camera 1 and the second camera 2 can be easily performed.

  As described above, according to the present embodiment, the color correction of the second camera 2 is performed based on the UV value of the UV signal of the first camera 1 and the UV signal from the second camera 2 stored in the memory 8. A calculation unit 9 for calculating the characteristic and a correction unit 11 for determining a parameter for color correction of the UV signal from the second camera based on the characteristic for color correction calculated by the calculation unit 9 are provided. Yes. For this reason, the color characteristics of the second camera 2 can be easily matched with the color characteristics of the first camera 1 without requiring complicated adjustment work and skill of the operator. As a result, it is possible to easily obtain a digital camera in which the color reproducibility of the first camera 1 and the color reproducibility of the second camera 2 are equal to each other.

(Embodiment 2)
Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 5 shows the configuration of a digital camera 100A according to Embodiment 2 of the present invention. The same components as those of the digital camera 100 according to Embodiment 1 described above with reference to FIG. 1 are denoted by the same reference numerals. Therefore, detailed description of these components is omitted.

  The camera 1 supplies RGB digital signals to the Y signal processing unit 4a, the C signal processing unit 5a, and the white balance adjustment unit 6a. The Y signal processing unit 4a generates a signal Y based on the RGB digital signal supplied from the camera 1, and outputs the signal Y to the switch 3A. The C signal processing unit 5a generates a signal U and a signal V based on the RGB digital signals supplied from the camera 1, and outputs the signals U and V to the switch 3A.

  The camera 2 supplies RGB digital signals to the Y signal processing unit 4b, the C signal processing unit 5b, and the white balance adjustment unit 6b. The Y signal processing unit 4b generates a signal Y based on the RGB digital signal supplied from the camera 2 and outputs the signal Y to the switch 3A. The C signal processing unit 5b generates a signal U and a signal V based on the RGB digital signals supplied from the camera 2, and outputs the signals U and V to the switch 3A.

  As described above, the first camera 1 and the second camera 2 each independently have a Y signal processing unit and a C signal processing unit. The switch 3A exclusively selects and outputs the YUV signal from the first camera 1 and the YUV signal from the second camera 2.

Next, a method for adjusting the first camera 1 and the second camera 2 using a standard color chart will be described. For the first camera 1, the parameters Y _off , U _off , V _off , Ky, Ku, Kv, b ₁₁ , b ₁₂ , b ₂₁ and b ₂₂ for color reproduction settings have been acquired in advance. It is assumed that it is stored in the memory 8.

  As in the first embodiment, the second camera 2 captures the standard color chart, and the calculation unit 9b calculates the above (Equation 9) and (Equation 10).

In the correction unit 11b, parameters Y _off , U _off , V _off , Ky, Ku, Kv, etc. for setting the color reproducibility of the second camera 2 so that the value of A in the above (Equation 10) becomes small. b ₁₁ , b ₁₂ , b ₂₁ and b ₂₂ are appropriately varied, and the varied parameters are supplied to the controller 7b. In this way, color matching between the first camera 1 and the second camera 2 can be easily performed.

  In addition, this invention is not limited to the said Example, It can implement variously in the range which does not deviate from the summary of this invention.

  For example, in the second embodiment, the characteristics relating to the color correction of the second camera 2 are calculated based on the UV value of the UV signal of the first camera 1 and the UV signal from the second camera 2 stored in the memory 8. Although the example in which the correction unit 11b corrects the UV signal from the second camera based on the characteristics relating to the color correction calculated by the calculation unit 9b and calculated by the calculation unit 9b is shown, the present invention is not limited to this. Based on the UV value of the UV signal of the second camera 2 stored in the memory 8 and the UV signal from the first camera 1, the calculation unit 9 a calculates the characteristics relating to the color correction of the first camera 1, and the calculation unit The correction unit 11a may correct the UV signal from the first camera based on the characteristics related to the color correction calculated by 9a.

  As described above, according to the present embodiment, color matching of a plurality of cameras can be facilitated and good color reproducibility can be obtained.

  The present invention can be applied to a digital camera having two or more cameras in a portable terminal or the like.

1 is a block circuit diagram illustrating a configuration of a digital camera according to Embodiment 1. FIG. FIG. 5 is a diagram showing a color filter array of a CMOS sensor provided in the digital camera according to the first embodiment. 1 is a block circuit diagram illustrating a configuration of a Y signal processing unit provided in a digital camera according to Embodiment 1. FIG. 1 is a block circuit diagram illustrating a configuration of a C signal processing unit provided in the digital camera according to Embodiment 1. FIG. FIG. 4 is a block circuit diagram illustrating a configuration of a digital camera according to a second embodiment. Block circuit diagram showing the configuration of a conventional digital camera The figure which shows the color filter arrangement | sequence of the CMOS sensor provided in the conventional digital camera. Block circuit diagram showing the configuration of a Y signal processing unit provided in a conventional digital camera A block circuit diagram showing a configuration of a C signal processing unit provided in a conventional digital camera

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 Camera 7 Control part 8 Memory 9 Calculation part 10 Memory 11 Correction part 100 Digital camera

Claims (7)

First and second cameras;
A digital camera comprising a memory for storing a first UV signal from the first camera;
A calculation unit for calculating characteristics relating to color correction of the second camera based on the first UV signal stored in the memory and the second UV signal from the second camera;
A digital camera, further comprising: a correction unit that determines a parameter for color correction of the second UV signal based on the color correction characteristic calculated by the calculation unit.   The digital camera according to claim 1, wherein the first and second cameras output RGB digital signals, respectively.   The digital camera according to claim 2, further comprising a switch that exclusively outputs either the RGB digital signal from the first camera or the RGB digital signal from the second camera.   The digital camera according to claim 3, further comprising a Y signal processing unit that generates a Y signal based on an RGB digital signal output from the switch.   The digital camera according to claim 3, further comprising a C signal processing unit that generates one of the first UV signal and the second UV signal based on an RGB digital signal output from the switch.   The digital camera according to claim 3, further comprising a white balance adjustment unit that calculates a white balance coefficient based on an RGB digital signal output from the switch. A first Y signal processing unit that generates a first Y signal based on the RGB digital signals output from the first camera;
A second Y signal processing unit that generates a second Y signal based on the RGB digital signal output from the second camera;
A first C signal processing unit that generates the first UV signal based on an RGB digital signal output from the first camera;
A second C signal processing unit that generates the second UV signal based on the RGB digital signal output from the second camera;
2. The digital camera according to claim 1, further comprising a switch that exclusively outputs one of the first Y signal, the first UV signal, the second Y signal, and the second UV signal.

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