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alter_igel

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Full Spectrum and Infrared Photography

timstr.website
67 points·by alter_igel·4 месяца назад·33 comments

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alter_igel
·2 месяца назад·discuss
I'm not familiar with the algorithm and I don't see much explanation on the site (at least on mobile) but AFAICT this is turning parenthesized infix expressions into reverse Polish notation. In other words, it takes human-readable mathematical formulas and converts them into something a simple stack-based machine can compute in one forward pass.

It also appears that separate digits aren't interpreted as decimal numerals (i.e. (1)(3) is the sequence 1,3 and not 13) which can look a bit misleading.
alter_igel
·2 месяца назад·discuss
I used to doodle and make pixel art on my TI 84+ in high school. I'd spend entire classes just clicking left, right, up, down, and enter to move and toggle individual pixels with a simple program I'd written. https://timstr.website/artwork/ti84plus.html
alter_igel
·4 месяца назад·discuss
Author here. Amazing work! The visible and thermal compositing is done really well and gives back so much detail and context that is lost in purely thermal images.

Does your IR camera give you access to raw temperature data? I've briefly played with a cheap thermal camera and it seemed to assign its own colours varyingly depending on the dynamic range of temperatures in view.
alter_igel
·4 месяца назад·discuss
Author here. I agree with you, "full spectrum" is a generous marketing phrase for what might more accurately be called _extended_ spectrum.

People way smarter than me have been able to achieve DIY spatial imaging with x-rays via compressed sensing [1] and with microwaves via phased arrays [2].

Optical wavelengths seem to be at a sweet spot of good angular resolution, varied natural sources, and harmless to humans.

[1] https://www.youtube.com/watch?v=EuVgGrun1V0

[2] https://www.youtube.com/watch?v=sXwDrcd1t-E
alter_igel
·4 месяца назад·discuss
Author here. Great point about the lens-dependent abberation, I mentioned this briefly in my earlier write-up about doing the full spectrum mod [1] but forgot to mention it by name here. I've been trying to get by without spending a lot of money on lenses and have gotten a lot of mileage out of a cheap used 50mm lens that _feels_ like it's just one or two solid glass elements. Fortunately the old camera mount I'm using means all the lenses for it are used, old, and super cheap secondhand. I'm about to try my luck with a 300mm lens. IR should be fun but we'll see if I can squeeze any UV at all through that.

Beautiful shots you have with your own full spectrum camera. Originally I somewhat dismissed the Kolari IR Chrome filter because the suggested combination with a channel swap and custom LUT felt a little too heavily edited for me and I prefer to stay close to the dry camera signal. The shot with the Tiffen Deep Yellow filter is gorgeous, how does that one look on the camera LCD without the channel swap?

[1] https://timstr.website/blog/diyfullspectrummod.html