Using a laser to blast away a Bayer filter array from a CCD
ruined 2021-08-18 17:14:49 +0000 UTC [ - ]
this is very exciting and i wonder if a similar process could be applied to consumer DSLR/MILC cameras. would love to shoot some high quality video in uv/ir
opencl 2021-08-18 17:57:55 +0000 UTC [ - ]
[1] https://maxmax.com/shopper/category/9241-monochrome-cameras
showerst 2021-08-18 19:06:50 +0000 UTC [ - ]
It's really an example of the best part of youtube, just a dude who knows some stuff explaining how things work and showing off shop-made projects.
userbinator 2021-08-19 03:58:04 +0000 UTC [ - ]
zokier 2021-08-18 17:49:53 +0000 UTC [ - ]
HeavenFox 2021-08-18 18:19:13 +0000 UTC [ - ]
However, astrophotographers also complain about the price premium of monochrome camera. Given the same sensor, the monochrome version is typically 20% - 30% more expensive than the color version, which is counterintuitive - you don't need to put the Bayer filter on! So if we can perfect the technique to debayer color sensor, the astrophotographer community would be elated.
ansible 2021-08-18 18:40:31 +0000 UTC [ - ]
The market for monochrome sensors is very tiny compared to the rest of the commercial products. Every phone now has 2 or more cameras on it, and there are billions of those.
Any changes to the manufacturing steps means more setup and effort. Different test procedures, quality control, documentation, etc.. That is all overhead, to be absorbed by a relatively small production volume.
I'm surprised it is only a 30% premium, I'd have expected higher actually.
spiantino 2021-08-18 20:00:54 +0000 UTC [ - ]
https://optcorp.com/products/zwo-asi6200mc-p - color $3999
https://optcorp.com/products/zwo-asi6200mm-p - mono $3799
2bitencryption 2021-08-18 21:07:45 +0000 UTC [ - ]
I wonder how long until phone cameras are purely monochrome, and apply ML to add the "correct" color in post-processing.
Actually, wasn't there some phone a few years ago with one high-res black-and-white sensor and one low-res color sensor, and it combined them through some tricky to produce a sharp color image?
barbazoo 2021-08-18 17:42:28 +0000 UTC [ - ]
_Microft 2021-08-18 17:43:37 +0000 UTC [ - ]
https://en.wikipedia.org/wiki/Bayer_filter
If you have a device that can output RAWs, you can look at a RAW image using the FOSS photo development program "Darktable". Choose "photosite color" as the "demosaic" filter to show the individual color channel values (and thereby the Bayer pattern of your camera).
But yes, after removing the filter, you have three times the number of pixels but you lost color information.
dr_zoidberg 2021-08-18 18:38:35 +0000 UTC [ - ]
Nowadays they classical algorithms are being replaced by convnets that are trained on different BFA/image pairs and can get very good results -- at the cost of placing a convnet in the middle (so much higher computational cost, which can be offloaded to a GPU/AI accelerator if available).
If you want to see what a "pixel perfect" camera gives you, there are the Sigma cameras with Foveon sensors[0] or you can check the cameras that have a sensor-shift superresolution approach (some pro Olympus and Hasselblad models have this feature). Sensor-shift SR has the problem that it works best on static scenes, because it takes several images which are then later combined on a single picture, and if there's movement between the images it may introduce a few artifacts.
[0] which do full color data for every pixel, as they use silicon depth to filter wavelenth
kragen 2021-08-19 05:28:01 +0000 UTC [ - ]
It also makes it harder to undo the effects of the demosaicking algorithm, which may be important if you're doing things like subpixel superresolution.
passivate 2021-08-18 20:59:50 +0000 UTC [ - ]
https://tinyurl.com/yyrndzkk
https://tinyurl.com/t9nnadc
gsich 2021-08-18 22:00:28 +0000 UTC [ - ]
passivate 2021-08-18 22:05:08 +0000 UTC [ - ]
https://www.dpreview.com/reviews/image-comparison/fullscreen...
gsich 2021-08-18 22:27:54 +0000 UTC [ - ]
karmakaze 2021-08-18 19:47:45 +0000 UTC [ - ]
dr_zoidberg 2021-08-18 20:38:09 +0000 UTC [ - ]
All in all, the BFA is "good enough" most of the times. For the use cases where it isn't, you're either:
* Budget constrained and can't really afford not using BFA
* Able to (pay for and) use either a color wheel in front of your sensor, or go with prism + triple sensor.
* Bite the bullet and go with a "strange" color array. You'll probably need to work on the software side for demosaicing to get proper support and fix eventual artifacts.
[0] even more green! 20/36 photosites are green, 8 red 8 blue
[1] with W being white, meaning no color filter or "panchromatic cell". In theory this helps on dim light conditions.
NathanielK 2021-08-19 09:15:04 +0000 UTC [ - ]
NathanielK 2021-08-19 09:13:09 +0000 UTC [ - ]
More importantly, green is close to what your eyes perceive as luminance. This is important because you can perceive a lot more luma detail than chroma detail. This is why things like 4:2:2 sampling work.
If you read Bayer's original patent, he proposed using Y Cr Cb (luminance, colour part red, colour part blue) instead of GBR filters[0]. This would people optimal from a computer science perspective. Sadly it doesn't work physically. Sensing negative-blue and negative-red can't really be done with a simple filter.
[0] https://patents.google.com/patent/US3971065
falcrist 2021-08-18 18:18:05 +0000 UTC [ - ]
I'm not exactly sure how the edge pixels are treated, but the difference in number between pixels and photosites should be on the order of a few thousand at most.
ansible 2021-08-18 18:34:39 +0000 UTC [ - ]
It is quite common to have more than the "nominal" number of pixels in a sensor array. So there are extra pixels for the edges.
falcrist 2021-08-18 18:43:26 +0000 UTC [ - ]
barbazoo 2021-08-18 18:25:10 +0000 UTC [ - ]
falcrist 2021-08-18 18:33:09 +0000 UTC [ - ]
This is obviously capturing less information than if you had a completely separate set of photosites for each pixel, but the megapixel count of cameras is nevertheless accurate.
Modern cameras sometimes come with a "pixel shift" function, which uses the image stabilization system to take 4 images each shifted one photosite from the others to construct an image where each pixel contains the information of 4 independent photosites with no sharing between the pixels.
The resolution of the final image is the same as a normal image, but the result is much clearer, and far less likely to suffer from blue/red moire.
2021-08-18 18:23:16 +0000 UTC [ - ]
AceJohnny2 2021-08-18 21:01:09 +0000 UTC [ - ]
The reason is that green actually captures much more of the luminance information, and our eyes have a much better luminance resolution than color resolution.
Tangentially, it's why the so-called YUV 420 (chroma subsampling) is so effective, where it's effectively encoding Y (luminance) data for every pixel (in a block of 4), but U/V (chrominance) only for every pair (or quad, someone correct me) of pixels.
There are examples online of pictures [1] with their luminance resolution decreased: you can immediately see the pixelation, and of their chrominance resolution decreased: you can barely tell the difference.
[1] https://en.wikipedia.org/wiki/Chroma_subsampling#/media/File...
AceJohnny2 2021-08-18 21:05:54 +0000 UTC [ - ]
Despite such a head start, Kodak went on to completely fail the analog-to-digital camera transition. A prime example of the Disruption Dilemma.
labcomputer 2021-08-18 23:41:12 +0000 UTC [ - ]
Edit: And there was really no feasible transition path for them anyway. The business depended on skimming a little bit for every photo taken. The main selling point of digital cameras was that you could take unlimited photos at no extra cost.
Customers aren't stupid. Even with patents, if you make the camera more expensive to account for the lost revenue on film and processing chemicals, people aren't going to buy it.
colonwqbang 2021-08-18 22:15:08 +0000 UTC [ - ]
Often, the chroma samples fall on pixels in even rows and on even lines. So pixels in odd rows or on odd lines, have to borrow (interpolate) their chroma values from neighbouring pixels.
barbegal 2021-08-18 19:11:46 +0000 UTC [ - ]
pjc50 2021-08-18 17:49:46 +0000 UTC [ - ]
ipsum2 2021-08-18 19:44:38 +0000 UTC [ - ]
ulfw 2021-08-19 05:39:14 +0000 UTC [ - ]
https://en.wikipedia.org/wiki/Minolta_RD-175