5 ms·

Using CMOS Sensors in a Cellphone for Gamma Detection and Classification

33 points by punnerud 5y ago

jeffbee 5y ago
"The cellphone has much more restrictive processing restrictions than desktop computers." Ah, things that were true ten years ago.
emilburzo 5y ago
I have this[1] Android app on my phone and try it out once in a while, it didn't pick up anything so far, which is probably good news. But I do wonder sometimes if it does actually work, i.e. it really would detect if something was there. https://play.google.com/store/apps/details?id=com.ImageInsightInc.GammaPixLite https://play.google.com/store/apps/details?id=com.ImageInsig...
- waste_monk 5y ago
  From what I've read it works well enough, but it's not terribly useful to most folk - given you're probably holding it in your hand while checking for radiation, if the camera is exposed, then so are you. Mostly useful as a "oh crap, I've been exposed to this much radiation???" dosimeter. Maybe invest in a selfie stick if you plan on going anywhere "hot" with only your phone, so at least you can peek it around corners. But Geiger counter are not that expensive - I picked up a GQ GMC-300E-PLUS for about $125 AUD a while back, which also detects beta radiation and has nice data logging capability, easy to use readouts, etc. (The 300E Plus is perhaps not a good example since it doesn't have a probe equivalent to the selfie stick idea, but comparing it to hand-holding the phone it is superior + I'm sure you could lash it to a stick if you really needed to)
sbdmmg 5y ago
Has anything changed significantly since 2014 that would make today's cellphones more efficient at detecting gammas? IIRC the tiny size of the cmos camera was the limiting factor...
- kurthr 5y ago
  The CMOS sensors have gotten much bigger (4-6x area plus there's multiple cameras) and the amplifiers are now almost thermal noise limited... but there's so much AI between you and the image that without using RAW it would be stomped out. I'm not sure how well the phone cameras would deal with cooling... since you don't really need the mechanical AF or zoom to work. That would be the next step, if you deconstructed them.
  - passerby1 5y ago
    Considering the size of modern sensors (48MPix and more) I doubt there's any hope for any continuous processing of Raw sensor data on the phone. Or is it?
    - kurthr 5y ago
      Agreed. You would want to black them out and set them for long exposures to minimize dead readout time. You can get RAW data out of iPhone Pros, though it's not something I've played with.

33 points by punnerud 5y ago

"The cellphone has much more restrictive processing restrictions than desktop computers." Ah, things that were true ten years ago.

emilburzo 5y ago

I have this[1] Android app on my phone and try it out once in a while, it didn't pick up anything so far, which is probably good news. But I do wonder sometimes if it does actually work, i.e. it really would detect if something was there. https://play.google.com/store/apps/details?id=com.ImageInsightInc.GammaPixLite https://play.google.com/store/apps/details?id=com.ImageInsig...

waste_monk 5y ago
From what I've read it works well enough, but it's not terribly useful to most folk - given you're probably holding it in your hand while checking for radiation, if the camera is exposed, then so are you. Mostly useful as a "oh crap, I've been exposed to this much radiation???" dosimeter. Maybe invest in a selfie stick if you plan on going anywhere "hot" with only your phone, so at least you can peek it around corners. But Geiger counter are not that expensive - I picked up a GQ GMC-300E-PLUS for about $125 AUD a while back, which also detects beta radiation and has nice data logging capability, easy to use readouts, etc. (The 300E Plus is perhaps not a good example since it doesn't have a probe equivalent to the selfie stick idea, but comparing it to hand-holding the phone it is superior + I'm sure you could lash it to a stick if you really needed to)

sbdmmg 5y ago

Has anything changed significantly since 2014 that would make today's cellphones more efficient at detecting gammas? IIRC the tiny size of the cmos camera was the limiting factor...

kurthr 5y ago
The CMOS sensors have gotten much bigger (4-6x area plus there's multiple cameras) and the amplifiers are now almost thermal noise limited... but there's so much AI between you and the image that without using RAW it would be stomped out. I'm not sure how well the phone cameras would deal with cooling... since you don't really need the mechanical AF or zoom to work. That would be the next step, if you deconstructed them.
- passerby1 5y ago
  Considering the size of modern sensors (48MPix and more) I doubt there's any hope for any continuous processing of Raw sensor data on the phone. Or is it?
  - kurthr 5y ago
    Agreed. You would want to black them out and set them for long exposures to minimize dead readout time. You can get RAW data out of iPhone Pros, though it's not something I've played with.