Causes
Many motion blur factors have existed for a long time in film and video (e.g. slow camera shutter speed). The emergence of digital video, and HDTV display technologies, introduced many additional factors that now contribute to motion blur. The following factors are generally the primary or secondary causes of perceived motion blur in video. In many cases, multiple factors can occur at the same time within the entire chain, from the original media or broadcast, all the way to the receiver end.
- Pixel response time on LCD displays (motion blur caused by slow pixel response)
- Lower camera shutter speeds common in Hollywood production films (blur in the content of the film), and common in miniaturized camera sensors that require more light.
- Blur from eye tracking fast moving objects on sample-and-hold LCD, plasma, or microdisplay.
- Resolution resampling (blur due to resizing image to fit the native resolution of the HDTV)
- Deinterlacing by the display, and telecine processing by studios. These processes can soften images, and/or introduce motion-speed irregularities.
- Compression artifacts, present in digital video streams, can contribute additional blur during fast motion.
Motion blur has been a more severe problem for LCD displays, due to their sample-and-hold nature. Even in situations when pixel response time is very short, motion blur remains a problem because their pixels remain lit, unlike CRT phosphors that merely flash briefly. Reducing the time an LCD pixel is lit, can be accomplished via turning off the backlight for part of a refresh. This reduces motion blur due to eye tracking by decreasing the time the backlight is on. In addition, strobed backlights can also be combined together with motion interpolation to reduce eye-tracking based motion blur.
Read more about this topic: HDTV Blur