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Archive for September 11th, 2017

Google Pixel XL Camera Oddity: LED Flicker Stripes

The Pixel’s camera shows a black stripe across both the live preview and the final image:

Pixel XL Camera - shutter stripe

Pixel XL Camera – shutter stripe

That’s under the high-intensity LED lamp on my desk, which must have a high-frequency flicker. I’m amazed the camera remains in absolutely stable sync with the flicker for as long as I’m willing to aim it.

The stripe covers only the moth and greenery, not the LCD monitor in the background, so it’s caused by the overhead lamp, not something internal to the Pixel or its camera.

A closer look shows shading on either side of the deepest black (clicky for more dots):

Pixel XL Camera - shutter stripe - detail

Pixel XL Camera – shutter stripe – detail

The stripe location and width differ based on the image zoom level, although in no predictable way:

Pixel XL Camera - shutter stripe - 2

Pixel XL Camera – shutter stripe – 2

The Pixel camera definitely doesn’t have optical zoom, so it’s surely related to the scaling applied to convert the physical sensor array into the final image. Even though all images have 4048×3036 pixels (or the other way around, at least for these portrait-layout pix), zoomed images get made-up (pronounced “interpolated”) data in their pixels.

Not a problem under any other illumination I’ve encountered so far, so it’s likely something to do with this specific and relatively old LED lamp.

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