Imaging Without Lenses
americanscientist.org
Imaging Without Lenses
1–10 of 28 posts
Re: Imaging Without Lenses
#2As I understand, one of the biggest costs of optical telescopes is the mirror, which needs to be meticulously ground to a paraboloid. Ever since I was a child, I always wondered if we could use a semi-cylindrical mirror (which is much easier to fabricate) to focus light into a linear sensor array and achieve the remaining focus computationally. If this is possible, we might be able to build much larger, cheaper versions of the James Webb Telescope.
I discovered 5 years back that cylindrical reflectors are not viable, purely optically: https://physics.stackexchange.com/questions/29853/are-cylind...
Re: Imaging Without Lenses
#3I believe that astronomers should have very special technics of data visualization, since almost all their data nowadays are non visual and they make stunning images. Sure some images are made just to become stunning, but they probably have technics to gather insights. These could be used in other high dimensionality scenarios.
Do you know some good references about astronomical data visualization?
Re: Imaging Without Lenses
#4Why does this sound like the real version of "Zoom. Enhance."
Re: Imaging Without Lenses
#5Why does this sound like the real version of "Zoom. Enhance."
I used to dismiss those obvious Hollywood cliches, but the more I looked into the space professionally, the less silly it sounds. Images-as-data are far richer than images-as-images, it turns out, and clever algorithms can extract a lot more information from them than you would naively expect.
So yeah, you're right!
Re: Imaging Without Lenses
#6I'm curious if you could DIY the mask used for example in FlatCam that they mention, it looks a really interesting area.
Apparently for the mask they use "a custom-made chrome-on-quartz photomask that consists of a fused quartz plate". I was wondering if you could make a very poor equivalent through just acetate and printing.
It vaguely reminds me of an old fashioned technique such as:
Re: Imaging Without Lenses
#7An extremely interesting read, but a very long article. Minimum of a 10 minute read.
Re: Imaging Without Lenses
#8I'm curious if you could DIY the mask used for example in FlatCam that they mention, it looks a really interesting area. Apparently for the mask they use "a custom-made chrome-on-quartz photomask that consists of a fused quartz plate". I was wondering if you could make a very poor equivalent through just acetate and printing. It vaguely reminds me of an old fashioned technique such as: https://en.wikipedia.org/wiki/Z…
This article the first instance I've heard of placing the mask directly on the sensor. I'd always had the impression that the coded aperture would be substituted for the original lens aperture. And the images I've found online seem to indicate that the aperture is macro-scale. This is something which could be imaged on lith film or hard-dot film.
I'd really like to play around with these techniques, but I don't know where to start. The only deconvolver I could find used Mathematica, so I'm not sure how useful making a coded aperture would be if I couldn't see the results.
Re: Imaging Without Lenses
#9As I understand, one of the biggest costs of optical telescopes is the mirror, which needs to be meticulously ground to a paraboloid. Ever since I was a child, I always wondered if we could use a semi-cylindrical mirror (which is much easier to fabricate) to focus light into a linear sensor array and achieve the remaining focus computationally. If this is possible, we might be able to build much larger, cheaper versi…
I can't quite visualize the problem. As long as you make the focal length of the first cylinder equal to the distance to the second cylinder + the distance from there to the sensor, and make the focal length of the second cylinder just the distance to the sensor, then both dimensions should converge at the right point?
Re: Imaging Without Lenses
#10I'm curious if you could DIY the mask used for example in FlatCam that they mention, it looks a really interesting area. Apparently for the mask they use "a custom-made chrome-on-quartz photomask that consists of a fused quartz plate". I was wondering if you could make a very poor equivalent through just acetate and printing. It vaguely reminds me of an old fashioned technique such as: https://en.wikipedia.org/wiki/Z…
This article the first instance I've heard of placing the mask directly on the sensor. I'd always had the impression that the coded aperture would be substituted for the original lens aperture. And the images I've found online seem to indicate that the aperture is macro-scale. This is something which could be imaged on lith film or hard-dot film. I'd really like to play around with these techniques, but I don't know…
You can do deconvolution using ImageJ, but getting a model of the PSF for an arbitrary aperture is the tricky part. https://imagej.net/Deconvolution