Display motion blur

In modern displays, motion blur is an unwanted artifact caused primarily by:

The faster the motion, the more pronounced the effect is.

Displays work by rapidly showing frames, each one slightly different from the previous, thereby creating the illusion of movement. Let's take a normal computer monitor with a resolution of 1920×1080 and a refreshrate of 60 Hz. If an object were to move across the display in 2 seconds, there would be 60×2 = 120 "steps", each one translated by 1920÷120 = 16 pixels. Your eyes, however, would not start and stop, over and over again to track the object, quickly moving the fovea to the "new" position of the object for 1000÷60 ≈ 16 milliseconds, only to do it again and again. Instead, your gaze would move across the display in a fluid motion, following the approximate location of said object. Because your eyes rotate to track something that doesn't actually move in a smooth, continuous motion, the image gets "smeared" across the retina. This mismatch is what causes motion blur, and explains why it doesn't occur when tracking physical objects; unlike the simulated motion on displays, real motion is actually continuous, whereas on a display, objects travel in a discrete steps. The experienced motion blur can be approximated purely as a function of persistence, similar to the shutter speed when taking pictures, because motion wise, it is actually the exact same thing, just from opposite frames of reference.

Motion clarity can be improved by decreasing the persistence, which is the amount of time the image is displayed for. Manufacturers use various names for their motion clarity enhancing technologies. Nvidia's implementation is called ULMB, Asus' ELMB, and BenQ Zowie uses DyAc and DyAc+. LG refers to black frame insertion on their OLED TV's as "OLED Motion (Pro)". The "pro" moniker denotes that BFI at 120 Hz is supported, as opposed to being limited to 60.

The key to reducing motion blur lies in decreasing the time the pixel stay illuminated. On liquid-crystal displays, this can be accomplished by strobing the backlight, whereas on OLEDs, this must be done by rapidly turning the pixels on and off, made possible by the fact that OLEDs have response times far shorter than those of LCDs. OLED TVs released 2020 & 2021 utilizing LG's WOLED panels feature black frame insertion at 120 Hz, with a duty cycle as low as 38%, resulting in a mere 3.2 ms of persistence. Due to the BFI, the experienced motion blur is comparable to that of a regular sample-and-hold OLED display running at roughly 310 Hz.

By quickly turning the backlight on and off ("strobing"), the image appears for a shorter amount of time. This reduction in persistence is what reduces motion blur. Different manufacturers use many names for their strobed backlight technologies for reducing motion blur on sample-and-hold LCDs.

Some displays use motion interpolation to run at a higher refresh rate, such as 100 Hz or 120 Hz to reduce motion blur. Motion interpolation generates artificial in-between frames that are inserted between the real frames. The advantage is reduced motion blur on sample-and-hold displays such as LCD.

There can be side-effects, including the soap opera effect if interpolation is enabled while watching movies (24 fps material). Motion interpolation also adds input lag, which makes it undesirable for interactive activity such as computers and video games.