Assessment of Image Quality Degraded by Tone Rendering Distortion

The tone rendering distortion index (TRDI), which assesses image quality degradation via the distortion within a display of the tone rendering curve (TRC), is introduced and investigated. The effect of the tone rendering distortion upon image quality is different from the effect of data-loss during image compression. The tone rendering distortion changes the lightness, hue and chroma, which results in degradation of an image into irregular patterns depending upon the shape of the distorted TRC. While peak-signal-to-noise ratio (PNSR) and color differences do not represent the image quality very well, the TRDI shows a strong agreement with the human-perceived image quality, despite its simplicity. The method is useful for developing new display technology as well as for refining the image processing within display systems.