When HD/UHD video is progressive-scanned and amped up by High Dynamic Range (HDR), the resulting picture quality can be stellar. Seen on a 4K TV, this remarkable image quality can leave viewers transfixed on the broadcast or stream theyre watching.

But the spell can be broken. It only takes one noticeable defect or artifact appearing somewhere in the imagery to distract viewers and leave them wondering, What was that? Did you see that? So, as picture quality steadily rises, its more important than ever to produce pristine video that dazzles rather than distracts.

In our previous blog, we looked at light and dark banding, flickering, and other anomalies that can result when LED video displays are shot by cameras designed with CMOS Rolling Shutter image sensors. In the time it takes these sensors to scan and output each video framesequentially line by line from top to bottomthe LED display has refreshed multiple times.

This mismatch between the imagers acquisition rate and the LED screens refresh rate causes annoying temporal artifacts such as banding and flickering that can become evident in the video. In fact, LED lighting, which is gaining in popularity to illuminate TV studio and location sets, can also challenge Rolling Shutter sensors and result in similar temporal artifacts.

Luckily, theres a fix for this. Its called CMOS Active Pixel Global Shutter image sensors. This advanced imaging method is revolutionary because Global Shutter sensors capture the contents of each video frame all at once, instead of line by line from top to bottom. With more circuitry devoted to each pixel, Global Shutter sensors scan each frame globally, meaning in its entirety, then output the scanned video frame. Since the video frame is captured instantly, like a snapshot, there isnt time for the LED display to repeatedly refresh, causing artifacts.

While its more expensive to manufacture CMOS Global Shutter image sensors than CMOS Rolling Shutter sensors, Global Shutter is worth it because its instantaneous acquisition makes temporal artifacts a thing of the past. This advanced imaging technology also eliminates the spatial distortions that are caused when fast moving objects or high-speed motion in the video is not acquired quickly enough, as is the case with Rolling Shutter sensors. Global Shutter resolves these spatial artifacts, which are known in the industry as: