Please can someone confirm the technology used by the R200 sensor module to collect depth data. Does it use structured light, stereoscopic cameras, time of flight or a combination of these?
Joe R. wrote:
OK thanks, does anyone know how susceptable the sensor is to sunlight?
Of course it will be very susceptible to sunlight, as sunlight contains a lot of IR light, and is very powerful. It is a difficult problem to solve. Think of it as trying to get a picture at night time, when no light is around, it is very hard. The solution there would be to put more light. The solution to your problem would be to remove the sunlight.
Interestingly, the R200 will be affected in two ways, the IR pattern will be absolutely covered by the sun, so you will not be able to see any pattern in the IR cameras. This leads to no depth reconstruction using structure light. However, having a good amount of IR light will benefit the passive IR stereo depth reconstruction part. You just need to make sure that the cameras are exposing correctly (you don't want to have completely white images because of over exposure).
Now, if you are more interested in an active sensor that would work in sunlight, you are asking for trouble, because the sun is extremely powerful compared to any type of light emitted by these sensors. There are some solutions out there that work better than others, specially time-of-flight sensors, like the absolutely amazing technology of the Kinect 2, or some other (very expensive) Lidars.
To be honest, it is better to use passive technologies when dealing with the sun, and even then it is tricky as the light changes all the time (I've worked processing data from smart security cameras, and I know how much those images can change).
Thanks both of you, that is very useful to know and we will be testing for our application over the next 2 weeks.
In terms of the passive depth sensing, is this in the SDK or has anyone had success using the left and right IR images to perform depth sensing? We will probably write our own algorithms that make use of structured light in low light conditions and passive stereoscopic in bright light conditions. Is this possible? Is there anything else we should be considering?
I'm not sure if, we can remove the IR filter attached to the cameras R200 using now. If so, we can modify it into the depth camera with both IR and ambient light, by making our own IR-filter glasses. When the sunlight was weak, we put the glasses on and the R200 just working as it is now; when outdoor, we take off the glasses, then R200 working as traditional stereovision camera.
But I don't know R200 using OV4682 RGB-IR module, like Project Tango, if so, theorotically we can make this "softly".