Environment Scanner #3


Environment Scanner Version 3

Scanner #3

Scanner #3 was going to be a killer! I had determined that I could address the environment in really small increments, so for example I could make a 512 x 512 image of a section of the environment sphere only 5 degrees on a side! This obviously required that I have an adjustable focal length lens so that my aperture (which limited the sample size) could be adjustable. I could over-sample, or under-sample, or adjust it according to the angles of the scan, wide barely overlapping samples to scan the entire environment at low resolution, or narrow samples to scan sub-sections and retain resolution. I had a 50-300mm Zoom for my Nikon, so I used a 2X extender to give me 100-600mm focal length.

I had a notion (which I still believe is possible) that you could build a really high resolution scanner, go to some exotic location, and scan it in. Then by mapping the info to a sphere, you could revisit the environment any time, and see the right thing no matter where you looked. This was before anybody ever used the term "virtual reality" or "Telepresence". (or "BubbleCam") HA!

I designed the lightbox so that I could use photomultiplier tubes and the nice dichroic splitter I already had, but initially I left it out, and just installed the one 1P21 photomultiplier I already had.

Here is one of the first mono scans from Scanner #3. It was taken in my living room in Chatsworth, California in 1986. Notice how the photomultiplier is able to pull out details over a much wider dynamic range. There is just something magical about the way those secondary emissions work, giving PMT's a beautiful natural logarithmic response to light, exactly what we're used to on film, and in the eyeball.

I did have some problems because the physical scanner had become quite large and heavy. I had planned to build a gearbox or pulley arrangement so that the whole rig didn't wobble quite so much between steps, but I never got around to it.

Here is a later scan of my workshop here in Kingsport, Tennessee. I still only have one PMT, but I'm searching for sources of more photomultipliers. If you know where I can get a couple of 1P21 PMT's and the PF-1048 power supply/socket assembly, please let me know!

Update: April, '96: Gary Smith to the rescue! After reading this Web Page, faithful InterNaut Gary Smith has donated a rare collection of PMT's from his collection. One of them is a huge "teacup" style PMT that could probably detect single neutrino's! This unexpected windfall, while welcome, has thrown a real monkey-wrench into my plans (What Plans?) trying to figure out the optimum way-cool way to use these beauties!

Thanks Gary!

Meanwhile, NetCams on the Web have given me the idea to build a modified environment scanner, Scanner #4.