Jerry Avins wrote:> Jerry Avins wrote to himself: > > nice pix! > > http://www.osa-opn.org/view_file.cfm?doc=%24)%2C7-K0%20%20%0A&id=%25(%2C%2B.J%3C4%20%0A >Think there is a parenthetical problem here somewhere. Right or left ?????
How things change
Started by ●March 3, 2005
Reply by ●March 4, 20052005-03-04
Reply by ●March 4, 20052005-03-04
"Richard Owlett" <rowlett@atlascomm.net> wrote in message news:112hrk960gj9hc0@corp.supernews.com...> Jerry Avins wrote: > > Jerry Avins wrote to himself: > > > > nice pix! > > > >http://www.osa-opn.org/view_file.cfm?doc=%24)%2C7-K0%20%20%0A&id=%25(%2C%2B.J%3C4%20%0A> > > > > Think there is a parenthetical problem here somewhere. > > Right or left ?????Worked fine for me...eventually (perhaps it's a really large pdf). Cheers Bhaskar
Reply by ●March 4, 20052005-03-04
Richard Owlett wrote:> Jerry Avins wrote: > >> Jerry Avins wrote to himself: >> >> nice pix! >> >> http://www.osa-opn.org/view_file.cfm?doc=%24)%2C7-K0%20%20%0A&id=%25(%2C%2B.J%3C4%20%0A >> > > > > Think there is a parenthetical problem here somewhere. > > Right or left ?????The software broke the link into parts. It's complete when intact. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
Reply by ●March 5, 20052005-03-05
Jerry Avins wrote:> Richard Owlett wrote: > >> Jerry Avins wrote: >> >>> Jerry Avins wrote to himself: >>> >>> nice pix! >>> >>> http://www.osa-opn.org/view_file.cfm?doc=%24)%2C7-K0%20%20%0A&id=%25(%2C%2B.J%3C4%20%0A >>> >> >> >> >> >> Think there is a parenthetical problem here somewhere. >> >> Right or left ????? > > > The software broke the link into parts. It's complete when intact. > > JerryWorked fine this time
Reply by ●March 5, 20052005-03-05
Jerry Avins wrote:> Early implementations of high-resolution side-looking synthetic-aperture > radar did the necessary 2D Fourier transforms optically. There was no > hope of using a computer of the day to calculate them.Optical signal processing was used in huge amounts for defence applications. It was used much more for sonar than for radar, I believe (at least, based on applications I know of, that is the case). Practically all the signal processing in torpedos, for example, was optical long after the radar business had become very DSP oriented. The optical solution was so much smaller and cheaper. DSP also had heat issues in the very confined spaces. Weird but true. You'd think cooling would be easy inside a steel tube in the water, but they always leave the guidance people with a tiny space. Regards, Steve
Reply by ●March 5, 20052005-03-05
Eric Jacobsen wrote:> My first job as an engineer doing signal processing was for Goodyear > Aerospace, the guys that pretty much invented Synthetic Aperture > Radar. Although I was working on the digital stuff, there were still > some optical processors floating around (and some still deployed in > the field) and plenty of old salts in the lab that had helped design > them. I found it really fascinating and being able to see, > side-by-side, how the optical processors worked to do the exact same > signal flow that we were doing digitally was very insightful. They > even had some cool ways to move the lenses slightly during processing > to compensate for the motion of the collecting airplane. Very cool > stuff, and very helpful in learning the whys and wherefores of a lot > of signal processing concepts.I always think of Goodyear in terms of some very nice digital architectures they had. Sad they never really went anywhere outside narrow defence applications. I think the ASPRO could have been huge if it had been driven hard in a more commercial way. I wonder if ut could have scaled in any sensible way to modern geometries, though. In my early days in DSP I used to get a little disheartened sometimes after doing huge jobs to build some neat piece of kit, only to find an extremely simple analogue gadget was already able to do roughly the same job. :-) Regards, Steve
Reply by ●March 5, 20052005-03-05
Eric wrote: ] Very cool stuff, and very helpful in learning the whys and wherefores ] of a lot of signal processing concepts. Way cool, Eric! Ciao, Peter K.
Reply by ●March 5, 20052005-03-05
On Fri, 04 Mar 2005 15:56:29 -0600, Richard Owlett <rowlett@atlascomm.net> wrote:>Jerry Avins wrote: > >> [snip] It strikingly brought the >> unity home to me, and convinced me that if I couldn't explain something >> to an intelligent and interested high-schooler, I didn't understand it >> well myself. Richard Feynman confirmed my opinion about that. >> > >OK, just how did he do it.I'll second the reference to Feynman's books, and I know exactly what Jerry's talking about. I felt a lot better about myself after reading Feynman's books knowing that he, one of the recognized True Geniuses of our time, thought about a lot of things in the same way that I do. He had low tolerance for pompousness, "honors", and things like that, and had a very refreshing way of bringing supposedly very complex things down to a very simple level. And he said he was always worried people would discover that he was faking it, and I've always related to that. ;) Very shortly after Dr. Feynman died the guy that had helped author his biographies was selling audio CDs with interviews with Feynman and some cuts of him playing drums with friends. I really treasure that, it's a great sample of a guy making it to the top without taking it too seriously and having a lot of fun along the way. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Reply by ●March 5, 20052005-03-05
On Fri, 04 Mar 2005 15:30:54 -0600, Richard Owlett <rowlett@atlascomm.net> wrote:>After reading Jerry's post, I started to ask a question. >But read your post and realized I might ask a specialist. > >1. Any WEB available references on how to do Fourier transforms optically?It's a single lens. Maybe a search on Fourier Transform Lens will turn something up.>1a. Can I assume the typical demo of interference effects from 2 slits >converting incident plane wave to 2 sources is a Fourier transform of >something? Can you tell I've not gone to school in decades ;]Not sure I undertand the question here...?>2. Did it depend on knowing the incoming carrier frequency? >IE Given an "optical Fourier transformer" as a 2-port black box. >Could you feed it an audio signal rather than RF and get out the >appropriate transform?I think so, and Steve indicated that sonar systems used it. The link Jerry provided is to a nice article by some guys at Sandia and has some pretty amazing SAR pics in it (being able to resolve footprints would've still been classified when I was working in this area), as well as a diagram showing an optical processing example (but it's a bit misleading, it doesn't show how the 2D cross-correlation is done). As long as the input can be modulated as a collimated light beam you can do the processing optically, so it should be reasonably independent of carrier frequency or bandwidth. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Reply by ●March 5, 20052005-03-05
On Sat, 05 Mar 2005 21:06:27 +0800, Steve Underwood <steveu@dis.org> wrote:>I always think of Goodyear in terms of some very nice digital >architectures they had. Sad they never really went anywhere outside >narrow defence applications. I think the ASPRO could have been huge if >it had been driven hard in a more commercial way. I wonder if ut could >have scaled in any sensible way to modern geometries, though. > >In my early days in DSP I used to get a little disheartened sometimes >after doing huge jobs to build some neat piece of kit, only to find an >extremely simple analogue gadget was already able to do roughly the same >job. :-) > >Regards, >SteveYeah, I remember the ASPRO, as well as the MPP (Massively Parallel Processor) that Goodyear made for the National Weather Service to do 3D sims. It was one of the first (if not the first) functional high-speed processors in a cube matrix architecture. If it's not still being used my understanding was that it had a really long useful life at NWS. It's funny how those little pockets of excellence pop up in funny places. Goodyear, including the defense research, was pretty much killed when financier Sir James Goldsmith did a stock raid on the company and forced them into a greenmail situation. The Goodyear board split the company up and sold off all the non-core businesses, like aerospace, the pipeline company, a shoe company, etc., etc., in order to pay Goldsmith off. The blimp technology went with aerospace and died there, so we have no new Goodyear blimps, either. Working there was one of my best employment experiences, ever. The place was fascinating. During lunch or breaks I'd wander around just to look at what was going on in the plant. I got to watch a blimp envelope being made, the hardened nuclear transporter for the midgetman missile (including an over-the-weekend repair when the prototype had a hydraulic fire during testing in Yuma), the chicken gun shooting at F-16 and B-1B windshields (transparent products division was there and also had a .50 cal machine gun to test bulletproof windscreens, very cool), and hardened/specialty shelter development for the military including a portable shelter with walls that allowed people to shoot out, but bullets coming in wouldn't penetrate. This was all in addition to the various SAR programs, some of which were quite black at the time (like the unit for the SR-71), and various other radar and antenna wizardry going on. Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
