tag:blogger.com,1999:blog-19092890.post6308150995098333956..comments2024-03-28T17:41:43.970+02:00Comments on Image Sensors World: 1550nm LiDAR Damaged Sony Camera at CESVladimir Koifmanhttp://www.blogger.com/profile/01800020176563544699noreply@blogger.comBlogger42125tag:blogger.com,1999:blog-19092890.post-10561628733088375772019-01-26T05:39:14.830+02:002019-01-26T05:39:14.830+02:00Small update: https://spectrum.ieee.org/cars-that-...Small update: https://spectrum.ieee.org/cars-that-think/transportation/sensors/keeping-lidars-from-zapping-camera-chips<br /><br />As reported above, AEye offered to buy the damaged camera, but apparently the owner "can't find it"...Peter Zimmernoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-14463649043443249782019-01-17T10:46:18.721+02:002019-01-17T10:46:18.721+02:00I think that the camera has a lens distortion corr...I think that the camera has a lens distortion correction inside. So a horizontal line seems curved when the lens distortion correction is applied on.YangNIhttps://www.blogger.com/profile/14424444367081117570noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-54054068962364986042019-01-17T10:38:46.429+02:002019-01-17T10:38:46.429+02:00If they use a fiber laser, then the peak power wil...If they use a fiber laser, then the peak power will be HUGE. A traditional laser diode can not provide a very high peak power simply it's too hard to generate a huge current pulse to drive the laser diode.YangNIhttps://www.blogger.com/profile/14424444367081117570noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-27388428127061428232019-01-17T03:20:45.101+02:002019-01-17T03:20:45.101+02:00just compare the different scene, if the curved pi...just compare the different scene, if the curved pixel is same, then it is not by software. magskyichttps://www.blogger.com/profile/01863338961197365344noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-37741776529402193752019-01-15T23:53:43.966+02:002019-01-15T23:53:43.966+02:00The sensor iis powered. Light sends something into...The sensor iis powered. Light sends something into conduction that shouldn't be (possibly causing SCR latchup?) and blows it out?<br />The energy then comes from a power supply. The too-intense light is a trigger.Oh wat mooihttps://www.blogger.com/profile/03727570712905579862noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-66286706000904676912019-01-15T23:45:22.608+02:002019-01-15T23:45:22.608+02:00It does seem this Lidar has a shorter range than s...It does seem this Lidar has a shorter range than some of their others so maybe only 100W, but that is still a lot of power to concentrate on an area which judging from the horizontal line on the image is not much bigger than 1 pixel. They may be retina safe, because the beam is absorbed by the "water" in the rest of the eye so doesn't reach the retina, but that doesn't mean it can't damage other things such as the lens (cataracts?) and other sensors such as our dashcams. Maybe they need a bit of independent research into safety before being allowed out in public, after all they are invisible, people can't tell when they are being scanned, if there are problems they won't normally be able to make the connection.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-66479426367906300992019-01-15T23:18:50.604+02:002019-01-15T23:18:50.604+02:00I fully agree with you on the lack of the solid kn...I fully agree with you on the lack of the solid knowledge on Aeye iDAR. That makes the whole discussion to be highly speculative. On the other hand, I doubt that somebody from Aeye would intervene and give us an info on this sensitive matter.Vladimir Koifmanhttps://www.blogger.com/profile/01800020176563544699noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-46949217868041726492019-01-15T21:29:01.403+02:002019-01-15T21:29:01.403+02:00Most of what one can do here is speculation due to...Most of what one can do here is speculation due to lack of any sort of spec from AEye and sparse data. I'm not convinced those artifacts don't predate that first image. I'm just trying to ground things in a back-of-envelope way to ameliorate fear of sensor (and eye) damage from what seems to me to be a pretty unlikely configuration.<br /><br />1) I had been assuming that the posted image was the exposure wherein damage had occurred, which is certainly disputable and I hadn't considered continuous readout/preview of a mirrorless sensor. But then you need multiple direct damaging hits of a small beam into a 8mm diameter aperture? If the shutter is open continuously and doing sustained damage, wouldn't you see some smear from the camera moving or lots of dots? <br /><br />2) That was my best guess of how you'd make that pattern if the damage occured in that image and I admit that was my interpretation. Not that it is necessarily any worse than other speculation occurring -- in fact it is specular speculation! The images available are of a low enough quality that it's hard to judge. I'd still be somewhat surprised if a direct hit of an eye-safe 1.5um laser could do that anyway through commercial camera optics. <br /><br />3) My point about cloud measurement is that a mW is a lot of light and the scaling properties for any lidar are pretty well known. I agree that the power requirements differ, but hard target ranging at these distances isn't a J/cm2 laser problem, which is where I think you'd need to be to see this kind of damage. Anything much above that is in danger of blatantly exceeding eye safety limits even at 1.5um. <br /><br />p.s. - long-time lurker and big fan of your site<br /><br />Peter Zimmernoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-41073629958638620272019-01-15T20:14:27.394+02:002019-01-15T20:14:27.394+02:00There are numerous safety measures one has to take...There are numerous safety measures one has to take to make this feasible but it's all within the standards. So can be done and surely is done.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-53430412987624157282019-01-15T20:03:14.591+02:002019-01-15T20:03:14.591+02:001. Sony mirrorless cameras have image sensor open ...1. Sony mirrorless cameras have image sensor open all the time due to a live preview. So, the time is not limited by the 1/60s exposure.<br /><br />2. Why do you think the laser is reflected off the column? There could be a direct hit during the live preview time.<br /><br />3. Tx power requirements depend on the target reflectivity, FoV, resolution and a measurement speed. In case of cloud monitoring, you probably mean single point measurement, narrow FoV, long integration time. In automotive LiDARs, the frame time is short, FoV is wide, angular resolution is high, and the target might be black. So, the Tx power requirements are different.<br /><br />4. Your curved horizontal line explanation looks very probable.Vladimir Koifmanhttps://www.blogger.com/profile/01800020176563544699noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-36305131641792873682019-01-15T19:42:55.501+02:002019-01-15T19:42:55.501+02:00Something about this doesn't add up. Laser dam...Something about this doesn't add up. Laser damage is notoriously difficult to predict due to a statistical nature of thresholds. But I've burnt some optics in the past and it took a bit of doing. <br /><br />35mm lens at f/4, 1/60 sec exposure. The laser has reflected off the column, from mulitple spots each with very different geometry and surface properties, into the 0.6 cm^2 aperture, through glass not optimized for 1.5um light and an IR cut (which probably leaks like crazy there), onto silicon that mostly transmits at that wavelength. <br /><br />There are not any published power specs that I can find for that system, but one could probably limit the power based on part costs, size and power requirements. 1W is probably a good upper limit and I doubt it's that much. It also has to NOT destroy the optical system designed to measure it. That system IS optimized to measure 1.5um and handle specular reflections from close up. <br /><br />To get a pencil beam backscatter off a hard target at the distances they advertise doesn't require all that much power. Measuring clouds that are kms away is a milliwatt problem. Close up stuff is more a matter of timing than power.<br /><br />Also notice the top-most artifact in the first image that doesn't replicate in the later images as charge generation site, the one with crossed dead row and column and no laser spot visible. Side note, there are enough CMOS experts here, is that what a laser damage site looks like on a color sensor? Do they bleed like that? (The curved line is probably caused by a distortion correction in the camera software.)<br /><br />All told it's conceivable but unlikely; it would be good to see the .RAW images. v It would also be good to see the .RAW images taken just before this.Peter Zimmernoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-20827314580446536162019-01-15T19:39:15.570+02:002019-01-15T19:39:15.570+02:00In case of Aeye, their tiny MEMS mirror suspended ...In case of Aeye, their tiny MEMS mirror suspended in vacuum severely limits the maximum power they can transmit. If I have to guess, their peak power is 100W or less. Vladimir Koifmanhttps://www.blogger.com/profile/01800020176563544699noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-63268168239448701282019-01-15T15:47:54.787+02:002019-01-15T15:47:54.787+02:00How powerful are these lasers? I tried to look it...How powerful are these lasers? I tried to look it up, but only came up with a figure of 8KW, which seems ridiculous!!! The pulses may be extremely small, so the average amount of power may be small, but that seems a highly dangerous amount of energy to be firing about in public, what if something goes wrong and it gets stuck on a single point for a somewhat longer time...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-49116338256399133142019-01-15T09:09:58.957+02:002019-01-15T09:09:58.957+02:00Agree, InGaAs APD is most probable. Sorry, I'm...Agree, InGaAs APD is most probable. Sorry, I'm not aware of any LiDAR tutorial.Vladimir Koifmanhttps://www.blogger.com/profile/01800020176563544699noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-23992620458364794342019-01-15T08:46:36.040+02:002019-01-15T08:46:36.040+02:00maybe a newbie question... what type of sensor is ...maybe a newbie question... what type of sensor is used for 1550nm Lidar? is it InGaAs based? but standard pixels or some kind of avalanche diode type to measure the echo of the laser pulse accurately? Is there some kind of basic tech overview for this IR laser based lidar systems you could recommend?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-53681274859607488492019-01-15T07:48:58.979+02:002019-01-15T07:48:58.979+02:00The worst case scenario in eye safety checks is wh...The worst case scenario in eye safety checks is when person puts his eye directly against the laser output window. In that case, it does not matter where this laser beam is directed to. If they passed that test, it's easier to be OK in any "interesting point."<br /><br />BTW, passing eye safety regulations is not a science. Rather, it's an art. There are many tricks and non-trivial ideas that can make the device certified eye safe, even if it emits a high laser power.Vladimir Koifmanhttps://www.blogger.com/profile/01800020176563544699noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-34995043172972575592019-01-15T05:47:51.499+02:002019-01-15T05:47:51.499+02:00>Getting back to the CES incident, what if Aeye...>Getting back to the CES incident, what if Aeye iDAR decided that this guy with his camera is an "interesting point" and put all its laser power on him?<br />Interesting point.. The eye safety should be determined by this worst scenario, I wonder if there is any documents based on this.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-46856726186318108282019-01-15T03:10:46.655+02:002019-01-15T03:10:46.655+02:00ok, just checked the news link and it is indeed a ...ok, just checked the news link and it is indeed a BSI sensor.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-38061005505287831002019-01-15T03:04:02.670+02:002019-01-15T03:04:02.670+02:00it will be interesting to know the model of this S...it will be interesting to know the model of this Sony camera. that will tell us if the sensor is a FSI or BSI sensor. if it BSI, the heat dissipation might not be good (I assume) and maybe more prone for local heat damage. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-76266815905402610602019-01-15T01:40:21.250+02:002019-01-15T01:40:21.250+02:00I agree that two photon absorption isn't reali...I agree that two photon absorption isn't realistic, but suspect might local plasmonic metal heating.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-62833721375870821212019-01-15T00:47:21.435+02:002019-01-15T00:47:21.435+02:00Also see: Sub bandgap laser-induced single event e...Also see: Sub bandgap laser-induced single event effects: carrier generation via two-photon absorption<br />https://doi.org/10.1109/TNS.2002.805337<br />This is a non-linear effect which depends on laser power. Notice that laser light is diffraction limit so it can focus into a very small spot size.Danialhttps://www.blogger.com/profile/14390890665100611929noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-30333234011435762082019-01-15T00:44:16.112+02:002019-01-15T00:44:16.112+02:00I agree it might look unrealistic, but I still thi...I agree it might look unrealistic, but I still think that this hypothesis deserves a small calculation before being ruled out completely. Consider that the laser is pulsed and thus the peak power can be huge, even though the average power is not so large. The camera optical system can also focus the laser beam in a very small spot, so the power density might be locally very large.Lucio Pancherihttps://www.blogger.com/profile/09182216560406064538noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-80374302419384948142019-01-15T00:25:47.385+02:002019-01-15T00:25:47.385+02:002-Photon absorption is a known issue in Silicon Ph...2-Photon absorption is a known issue in Silicon Photonics. But you need quite a photon density to yield a significant Probability of exciting an electron into conduction band. Hence, 2photon microscopy works with such high resolution. What laser intensity is needed to yield a realistic probability of yielding enough carriers to heat up silicon at a realistic beam divergence and given distance? I didn't do the math, but it sounds unrealistic that this is the issue...Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-19092890.post-73697719362528575902019-01-14T23:47:49.993+02:002019-01-14T23:47:49.993+02:00Two-photon absorption of 1550nm focused laser ligh...Two-photon absorption of 1550nm focused laser light has already been observed in silicon PIN photodiodes and image sensors:<br />https://tmo.jpl.nasa.gov/progress_report/42-173/173C.pdf<br />This effect can be probably taken into account in this case.<br />Lucio Pancherihttps://www.blogger.com/profile/09182216560406064538noreply@blogger.comtag:blogger.com,1999:blog-19092890.post-13127037024790109052019-01-14T23:36:12.520+02:002019-01-14T23:36:12.520+02:00Then it must be very strong laser, I tried my 30mW...Then it must be very strong laser, I tried my 30mW gren laser pointer before, can hardly damage like this.magskyichttps://www.blogger.com/profile/01863338961197365344noreply@blogger.com