Cross-Display-Technology Video Motion Measurement Tools

摘要

High performance video places severe demands on playback system and display device resources. Motion playback errors such as irregular motion playback and image breakup are common, making accurate -measurement of motion critically important for device selection and system tuning to ensure the desired viewing experience. Direct observation of the actual displayed image (screen capture) is the only way to perform a complete end-to-end system test that accounts for all possible sources of motion errors, including original video capture, compression/decompression, playback system performance, and display device operation. Unfortunately for the development of measurement techniques, the fundamentally different ways that different display technologies present imagery can easily confound sensitive measurement techniques, producing measured playback performance differences across multiple display technologies such as LCD (liquid crystal display), plasma, CRT (cathode ray tube), and DMD (digital micromirror device) that are disproportionately large compared to the actual differences (if any) seen by a human viewer. Cross-technology measurement tools are necessary to ensure the validity of measures across multiple technologies. The methods being used include a combination of test materials (both selected live video clips and synthetic clips), capture technique (including control of capture rate, triggering, and timestamping), and analysis. This paper describes these methods, then gives several illustrative examples of the use of these methods by the project. The MIST Motion Image Quality Measurement project uses a combination of quantitative measures and subjective analysis to evaluate motion imagery and to identify the factors that determine overall performance. The NIST project has conducted tests to measure (1) perceived image quality and (2) motion image interpretability, as a function of factors including compression, video motion and other scene content, playback system performance, and frame rate. Tests have been conducted using a variety of playback systems with different levels of performance and using a variety of display technologies.