Andrea B. Posted July 27, 2019 Share Posted July 27, 2019 CITATION:Samartzidis, T., Siegmund, D., Gödde, M., Damer, N., Braun, A., & Kuijper, A.: The Dark Side of the Face: Exploring the Ultraviolet Spectrum for Face Biometrics In: IEEE Computer Society: 2018 International Conference on Biometrics (ICB). - IEEE Computer Society Press, 2018, 8 p., ISBN 978-1-5386-4285-6 EXCERPT:For the UV capturing, a Baumer VCXG-13M camera with a 1/2 CMOS sensor, 1280x1024 pixel resolution and a sensitivity starting at 300nm was used. In order to receive best response of UV-MFP, we filtered the visible light in the captures by using a UV/IR bandpass filter (Schott UG11) which has its peak transmission at 300nm and blocks light with wavelength over 400nm. Furthermore a quartz lens was used to increase the light transmission in that wavelength. For illumination we used two 36W UV-A LPS lamps with a bandwidth between 315nm and 400nm positioned in front left and front right to the subject. In Figure 2 the sensitivity of the camera sensor, the transmission of the used filter and the emission of the used illumination in UV spectrum is shown. FIGURE 2: I am curious about the filter having a peak at 300 nm and blocking past 400 nm? This doesn't seem like it could be just plain UG11 do you think?Also, if the lamp has bandwidth between 315-400 nm, then why does the chart show the lamp stopping just before 350 nm? . Link to comment
ulf Posted July 27, 2019 Share Posted July 27, 2019 I am curious about the filter having a peak at 300 nm and blocking past 400 nm? This doesn't seem like it could be just plain UG11 do you think?Also, if the lamp has bandwidth between 315-400 nm, then why does the chart show the lamp stopping just before 350 nm? . The text do not match the graphs, but the filter curve is quite similar to an UG11, 1mm. Conveniently their graph stop at 650nm, just before the IR-bump. The light source in the graph seams to be a hand drawn curve intended to look as an UV-LED ca 650nm. Link to comment
dabateman Posted July 28, 2019 Share Posted July 28, 2019 Andrea,There is something seriously wrong with this sentence:"For illumination we used two 36W UV-A LPS lamps with a bandwidth between 315nm and 400nm positioned in front left and front right to the subject. " A low pressure sodium lamp (LPS) has zero UV. That might be a manufacturer I am not aware off.But its possible they are using some light that ends at 350nm. Like a black compact fluorescent bulb. I was surprised how monochromatic my compact fluorescent black light were when tested here:https://www.ultravio...rescent-lights/ Link to comment
Andrea B. Posted July 28, 2019 Author Share Posted July 28, 2019 We can only hope there was no ambient IR in the experimental setting! Link to comment
Andrea B. Posted July 28, 2019 Author Share Posted July 28, 2019 Found another paper about UV facial recognition. It looks to me like those poor people in the experiment were UV-flashed with their eyes open? Yikes!!!! This is a PDF link.Can we match Ultraviolet Face Images against their Visible Counterparts? This group of researchers was using a medical UV imaging system made by Faraghan Medical Camera Systems. The gear is based on a Canon DSLR, has two flashes and is mounted on a frame suitable for facial photographs. I'm not sure what is in the hotshoe. Another flash?They have a gallery of faces. Some of their subjects, but not all, have their eyes closed. Interesting remark on their website:Now we have the only portable digital UV camera on the market.I'm thinking this must be in the context of a medical office where they can roll the setup around from place to place? Yes, that must be it. Here is a good article from their site: http://uvcamera.com/.../Aesthetic2.jpg Link to comment
JMC Posted July 28, 2019 Share Posted July 28, 2019 I don't even know where to begin with that setup in post #5 Andrea. I followed the link to the website, and found the following statement - "We maximize the Canon’s Digital SLR CMOS sensor to be most sensitive sensor in the UV range on the market!" That's quite a statement. Did you find a transmission spectra of their filter anywhere - they say they are using their own filter? As for the only portable system, what a load of rubbish. Either their understanding is about 10 years out of date, or they haven't bother looking around. Link to comment
Andy Perrin Posted July 28, 2019 Share Posted July 28, 2019 Or they are simply lying. Advertisers do that. Link to comment
Andrea B. Posted July 29, 2019 Author Share Posted July 29, 2019 Capitalism vs. Science: Round #1,879,234,449,876. Link to comment
Andrea B. Posted July 29, 2019 Author Share Posted July 29, 2019 A broader point: The Faraghan founder had a good idea. The parts are simple: a converted camera, some flashes with UV-pass filters, a UV-capable lens, a bunch of aluminum tubing and a chin cup. Buy for cheaps, sell for thousands. Anyone of you here could start this business and perhaps make a few dollars/euros/pounds/bitcoins. I would include little eye-cover googles to block the UV flash. Link to comment
JMC Posted July 29, 2019 Share Posted July 29, 2019 Reminds me of the old snake oil salesmen..... Link to comment
Andrea B. Posted July 29, 2019 Author Share Posted July 29, 2019 All advertising is snake oil!! :lol: Link to comment
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