The RIQA—Camera Color Analysis Module is used to evaluate the color metrics of imaging systems, including data on color difference, luminance, saturation, and other aspects. This module supports testing with standard 24-color, 140-color, and 14-color charts.

Test charts supported by the color module:

24-Color
Operation Steps
(1) Open the software and select “24-Color” in the “Color” module. (2) Click “Add” to import the image to be analyzed. (3) Select the image and click “Start” to proceed to the next step. (4) Fine-tune the ROI and click “Analyze” to proceed to the next step. (5) View the analysis results. (6) Click “Generate Report”, enter the file name, select the save directory and file format, and click “Export” to view the saved report in this path.

Result Interpretation
(1) Color Difference Chart
This chart shows the positions of each color patch on the color chart in the $ CIE$ $L_{ab}$ color coordinates, where the horizontal axis is a* and the vertical axis is b*. Negative values of a* indicate green, and positive values indicate magenta; negative values of b* indicate blue, and positive values indicate yellow. The squares (a*, b*) represent the theoretical positions, and the circles (a*, b*) represent the actual measured values from the camera. The difference between the theoretical and actual points is the color difference of the camera. The color coordinate values for each patch can be viewed in the generated report, with patches numbered 1-24 in order from left to right and top to bottom.

(2) Grayscale Patch Fitting
This chart shows the density response obtained from the grayscale patches at the bottom of the chart. It includes first-order and second-order fits (blue and green dashed lines). The horizontal axis is LogExposure (minus target density). Gamma (contrast) is the average slope of the log pixel level relative to the log exposure, calculated for the 2nd to 5th gray patches at the bottom (excluding the white and black patches).

(3) Grayscale Patch Pixel Value Interface
This chart shows the pixel value variation from left to right for the grayscale patches on the color chart, where the horizontal axis is pixel distance and the vertical axis is pixel value.

(4) Grayscale Patch SNR Interface
This chart shows the SNR curve for the grayscale patches on the color chart, where the horizontal axis represents the gray patches on the chart and the vertical axis represents the signal-to-noise ratio. It displays the signal-to-noise ratio (SNR) of each grayscale patch, providing a simple overview of the camera's noise performance.

Actual Measured Data:

(1) Chroma(%): Image saturation.
(2) Theta, Distance(B): Angle relative to the U-axis and distance relative to the origin of the 13th patch in the LUV space.
(3) Theta, Distance(G): Angle relative to the U-axis and distance relative to the origin of the 14th patch in the LUV space.
(4) Theta, Distance(R): Angle relative to the U-axis and distance relative to the origin of the 15th patch in the LUV space.
(5) Theta, Distance(Ye): Angle relative to the U-axis and distance relative to the origin of the 16th patch in the LUV space.
(6) ΔE00(patch1): CIE2000 ΔE color difference value for the first sampled patch.
(7) ΔC00(patch1): CIE2000 ΔC color difference value for the first sampled patch.
(8) ΔE00(patch2): CIE2000 ΔE color difference value for the second sampled patch.
(9) ΔC00(path2): CIE2000 ΔC color difference value for the second sampled patch.
(10) Mean ΔC00 corr: Mean ΔC color difference of the corrected image in the CIE2000 Lab color space.
(11) Sigma ΔC00 corr: Standard deviation of the ΔC color difference of the corrected image in the CIE2000 Lab color space.
(12) Max ΔC00 corr: Maximum ΔC color difference of the corrected image in the CIE2000 Lab color space.
(13) Mean ΔC00: Mean ΔC color difference of the corrected image in the CIE2000 Lab color space.
(14) Sigma ΔC00: Standard deviation of the ΔC color difference of the corrected image in the CIE2000 Lab color space.
(15) Max ΔC00: Maximum ΔC color difference of the corrected image in the CIE2000 Lab color space.
(16) Mean ΔE00: Mean ΔE color difference of the corrected image in the CIE2000 Lab color space.
(17) Sigma ΔE00: Standard deviation of the ΔE color difference of the corrected image in the CIE2000 Lab color space.
(18) Max ΔE00: Maximum ΔE color difference of the corrected image in the CIE2000 Lab color space.
(19) ΔC_WB: Mean ΔC of the middle four grayscale patches, used to check the white balance of the image.
(20) ΔC00_WB (max gray): Maximum ΔC value among the six grayscale patches calculated according to the CIE2000 standard.
(21) Gamma: Measured Gamma value of the grayscale patches, which can be used to correct image color differences.
(22) Exp_err: Exposure error.
(23) SNR(dB): Measured signal-to-noise ratio of the grayscale patches.
(24) S(patch20): S value of the 20th patch in the HSV color coordinates.
(25) S(patch21): S value of the 21st patch in the HSV color coordinates.
(26) S(patch22): S value of the 22nd patch in the HSV color coordinates.
(27) S(patch23): S value of the 23rd patch in the HSV color coordinates.
(28) Y(patch22): Y value of the 22nd patch in the HSV color coordinates.
(29) Contrast Ratio: Image contrast.
(30) Pixel Aspect Ratio: Pixel aspect ratio.

140-Color
Operation Steps
(1) Open the software and select “140-Color” in the “Color” module. (2) Click “Add” to import the image to be analyzed. (3) Select the image and click “Start” to proceed to the next step. (4) Select the area to be analyzed and click “Next”. (5) Fine-tune the ROI and click “Analyze” to proceed to the next step. (6) View the analysis results.

14-Color
Operation Steps
(1) Open the software and select “14-Color (1128)” in the “Color” module. (2) Click “Add” to import the image to be analyzed. (3) Select the image and click “Start” to proceed to the next step. (4) Select the area to be analyzed and click “Next”. (5) Fine-tune the ROI and click “Analyze” to proceed to the next step. (6) View the analysis results. (7) Click “Generate Report”, enter the file name, select the save directory and file format, and click “Export” to view the saved report in this path.

Result Interpretation
(1) Theta(R,Left): Left red hue angle.
(2) Theta(R,Right): Right red hue angle.
(3) Theta(G,Left): Left green hue angle.
(4) Theta(G,Right): Right green hue angle.
(5) Theta(B,Left): Left blue hue angle.
(6) Theta(B,Right): Right blue hue angle.
(7) Theta(Ye,Left): Left yellow hue angle.
(8) Theta(Ye,Right): Right yellow hue angle.
(9) Distance(R,Left): Left red color distance.
(10) Distance(R,Right): Right red color distance.
(11) Distance(G,Left): Left green color distance.
(12) Distance(G,Right): Right green color distance.
(13) Distance(B,Left): Left blue color distance.
(14) Distance(B,Right): Right blue color distance.
(15) Distance(Ye,Left): Left yellow color distance.
(16) Distance(Ye,Right): Right yellow color distance.