Concept
CMS Color Reproduction refers to the ability of the Camera Monitor System (CMS) to accurately reproduce the colors of the original scene on the in-vehicle monitor after capturing the scene information around the vehicle via external cameras, followed by image processing and transmission. It encompasses the precise reproduction of color attributes such as hue, saturation, and lightness, ensuring that the colors displayed on the monitor match the inherent colors of objects in the actual scene or fall within an acceptable deviation range.

Color is crucial for drivers to recognize traffic lights, road markings, and other road condition information. Accurate color reproduction is the foundation of driving safety, and its reproduction capability is also a compliance requirement for the mass production and road use of CMS. The color reproduction test verifies whether the DUT's reproduction of the target chart colors meets the standards, ensuring the safety and reliability of the CMS.

Metrics (ISO 16505 6.8.3):
For color reproduction, the hue angle of the reproduced colors of the chart patches on the monitor shall meet the following requirements. The color coordinates are described based on the CIE 1976 color space:
— The coordinates of the red patch shall not exceed the range of [0°, 44.8°] or [332.2°, 360°];
— The coordinates of the green patch shall not exceed the range of [96.6°, 179.9°];
— The coordinates of the blue patch shall not exceed the range of [209.9°, 302.2°];
— The coordinates of the yellow patch shall not exceed the range of [44.8°, 96.6°];
— To ensure distinguishability from the white patch, the distance to white is limited to Ri ≥ 0.02, where Ri is the chromaticity distance of each patch (i = red, green, blue, yellow) relative to white (i = white).
For the reproduction of traffic lights, the yellow light shall be recognizable as yellow, the blue light as blue, and the red light as red.

Method (ISO 16505 7.8.3):
Based on the color reproduction test chart, an imaging luminance meter is used to capture the monitor screen. The color reproduction capability of the CMS is quantified by measuring the color coordinates of each individual patch, as well as the chromaticity angle and Euclidean distance from each patch to the reference white patch.
Test Environment

Color Reproduction Test Equipment Setup

Camera side: light source color temperature 6500K ± 1500K, 500 ± 50 lx;
Monitor side: dark environment with illuminance below 10 lx.

Main Equipment Used:
Automated Chart Switching Bracket Test System, Multi-CCT LED Supplemental Light Source (Visible and NIR), Color Reproduction Test Chart, 2D Imaging Luminance Meter, RIQA-CMS Image Quality Analysis Software, Monitor and Luminance Meter Mobile Stand

Operating Procedures:
Camera Side:

1. Switch the chart to the color reproduction chart;
2. Turn on the chart supplemental light source, ensuring the camera's optical axis is perpendicular to the chart;
3. Adjust the distance between the camera and the chart so that the background of the color reproduction chart occupies approximately 50% of the display screen.

Monitor Side:

1. Position the capture lens perpendicular to the monitor;
2. Turn off other light sources to ensure the ambient illuminance on the monitor side is below 10 lx;
3. Capture images using the 2D imaging luminance meter.

Analysis and Interpretation:
Use RIQA Software (an image quality software independently developed by Yanding) to analyze the test samples.