Type of Display: This test is primarily designed for LCD displays (steady backlight, sample-and-hold displays).
Instructions: Watch the UFO. Slowly adjust the "Pixel Per Frame" by 1 until background looks like a perfect checkerboard with the dark and light squares as exactly the same size as possible. Once this is done, this will be your display's measured "Moving Picture Response Time" (MPRT) / measured "Motion Clarity Ratio" (MCR).
MPRT is not the same thing as GtG. See TestUFO: GtG versus MPRT. Moving Picture Response Time (MPRT) is display persistence. GtG is the pixel transition time, while MPRT is pixel visibility time. MPRT can still create a lot of display motion blur even if pixel response (GtG) is instant. MPRT is a more accurate representation of visible motion blur blur (see Eye Tracking Motion Blur Animation demo). For the scientifically ideal instant-response sample-and-hold display, MPRT is exactly equal to the time period of one refresh cycle. For the scientifically ideal impulse-driven display (e.g. square-wave strobe backlight), MPRT is exactly equal to strobe flash length. (see Black Frames Insertion Animation). MPRT is also known in some industry circles as "persistence". However, the more scientific term is Moving Picture Response Time (MPRT) found in science papers on Google Scholar. For more information about display persistence, see Blur Busters Law.
Motion Clarity Ratio (MCR) is equal to 1000 divided by MPRT. Similiar terms are sometimes used by TV manufacturers ("Clear Motion Ratio", "Motion Clarity Index", etc.)
to represent an equivalence to a refresh rate. Techniques such as frame-interpolation and impulse-driving (scanning backlights, strobing) frequently combine to
create higher Motion Clarity Ratios (MCR). It represents the same perceived display motion blur as an ideal sample-and-hold display refreshing at a Hz matching the MCR value.
This test allows you to measure the actual correct representative number as seen by the human eye, which may sometimes be lower than advertised numbers.
Note: This motion test is compatible with impulse-driving. However, this motion test will not work with frame-interpolation. this motion test is incompatible with frame-interpolating displays.
- For more accurate measurements, do both black/white and inverse white/black tests, and average the results. LCD GtG pixel transitions are often asymmetric.
- A larger "Size" setting allows a more accurate measurement. However, faster displays and higher refresh rates are easier with a smaller "Size" setting.
- With lower-persistence displays and/or high refresh rates, try using smaller Checkerboard Size numbers. Avoid Thickness values bigger than Checkerboard Size.
- Strobe backlight technologies (e.g. ULMB and LightBoost) often have MPRT values of 1ms to 2ms, and may require Checkerboard Size of 1 or 2 to measure.
- Do not strain your eyes. Test for short periods at a time. Rest your eyes between tests.
- Avoid using this test if you are prone to epilepsy.