4 ms·
Readout of a CCD is destructive. There are types of sensors that have non-destructive readout (Charge Injection Devices being one example: https://www.cis.rit.e
by EvanAnderson 11y ago
Readout of a CCD is destructive. There are types of sensors that have non-destructive readout (Charge Injection Devices being one example: https://www.cis.rit.edu/research/CID/a_cid_is.htm https://www.cis.rit.edu/research/CID/a_cid_is.htm).
- StavrosK 11y agoVery interesting, thank you.
- kps 11y agoA sensor with per-pixel reset to zero on readout would seem to be ideal — then you could get cumulative counts without wasting valuable photon landing space on the die.
- kuschku 11y agoOkay, but can’t I take 8 raw images and merge them into one image with 8 times higher dynamic range?
- KingMob 11y agoYes, but if I understand correctly, unless those images occur at the same time (or really, really close) you run into issues involving subject and camera motion.
- altcognito 11y agoYes, that's what modern cameras with the built in feature do. (although I'm not sure about 8 times) The article talks about this feature.
- kuschku 11y agoYes, but why can’t the camera do it continuously? Film at 240fps and provide a 60fps output with 10bit color depth.
- pto0239hn 11y agoBecause the images would look funny. Imagine you're capturing someone running - at frame 1, they would be at position x, and at frame 2, they'll be at position x + 1. If you try to stack them together, you'll get a weird ghosting effect.
- kuschku 11y agoWell, that ghosting effect is also called motion blur. If I integrate continuously, that is.
- pto0239hn 11y agoMotion blur, but different parts of the image would be exposed differently due to the nature of HDR, resulting in an odd look. Imagine instead of a runner, that you're panning from a dark to light scene.
- kuschku 11y agoNot necessarily. Assume we say an 8-bit image is taken every 0.1 second, if I merge 4 of them, wouldn’t I just get a 10-bit image with 0.4 second shutter time? Because I essentially just take the RAW image, load them into a 10-bit colorspace, add them up, and then store the image.
- dandelany 11y agoOf course - that's the current standard way to produce HDR photos. The advantage here is being able to do it all in a single image, which prevents mismatches between images due to subject or photographer movement.