Perceptual Color Volume Certification for Display Products

Perceptual color volume is an advanced concept that captures the full spectrum of colors perceivable by the human eye on a display, extending beyond the traditional color gamut to include the brightness levels at which these colors are visible. This approach amalgamates the color gamut with a display's luminance, crafting a three-dimensional visual representation of all possible colors at varying levels of brightness, offering a more holistic view of a display's color capabilities.

Traditionally, color gamut coverage has been measured in two dimensions, assessing a product's ability to reproduce a target range of colors. However, this method, based on the CIE1931 or CIE1976 color gamut models, lacks critical luminance data, leading to inaccuracies and an incomplete portrayal of a product's true color potential, often missing the mark on subjective user experience.

While organizations like IEC, SEMI, and SID have made strides in proposing measurement and evaluation systems for three-dimensional color gamut, these standards are not without their challenges. Limitations such as a restricted number of colors measured can result in inconsistencies within the color space, highlighting the need for a more refined and comprehensive standard that fully encapsulates the nuances of color perception.

The significance of perceptual color volume lies in its alignment with the human eye's sensitivity to color variations at different brightness levels. Displays with a high perceptual color volume can render colors that are more vibrant, nuanced, and true-to-life across an extensive range of luminance, enhancing the realism and immersion of the visual experience. This aspect is crucial in fields where color fidelity and display excellence are paramount, such as in photography, film, and design.

To develop a color gamut that more accurately reflects the visual capabilities of the human eye, TÜV Rheinland has partnered with the Color Engineering Laboratory at Zhejiang University to conduct a year-long experimental study. The goal was to determine which color model most effectively predicts human color perception. The findings indicate that color spaces constructed using the CIE CAM16 color appearance model are superior in mirroring human color perception, ensuring consistency and uniformity across the entire color gamut. Additionally, the research confirmed that increasing screen brightness enhances the breadth of colors perceived by the human eye, further validating the importance of considering luminance in color representation.

TÜV Rheinland launched the Perceptual Color Volume Certification Service, aimed at scientifically measuring and calculating the color range of a display device under default viewing conditions. This service measures the color coordinates of 4096 colors and constructs a three-dimensional color volume shape under the CIECAM16UCS. The volume is then calculated using the Gamut Volume algorithm, resulting in the device's perceptual color capacity as seen by the human eye under 1000 lux lighting conditions. In the Perceptual Color Volume Service, we primarily assess the following indicators:

• The size of the perceptual color capacity;
• The overlap rate of the color gamut in three-dimensional space;
• The color accuracy of 4096 colors;
• The retention of the color gamut at different grayscale levels.

• Smart phones
• tablets
• laptop computers
• display monitors
• automotive screens
• televisions
• Accessories like screen protector, etc