topic Re: Light sensor on d435 in Items with no label

Light sensor on d435

YHirs1 — Thu, 04 Oct 2018 11:04:37 GMT

Hello!

I am trying to figure out how can I get the output value of the light sensor that implanted on d435.

Since the color camera has an auto exposure mode and auto white balance mode, I supposed that the light sensor value can be reached somehow.

Hope you can help me with that.

Re: Light sensor on d435

MartyG — Thu, 04 Oct 2018 11:26:56 GMT

A RealSense SDK 2.0 sample program called 'Sensor Control' can be used to query the settings of the supported sensors on a camera.

https://github.com/IntelRealSense/librealsense/tree/master/examples/sensor-control librealsense/examples/sensor-control at master · IntelRealSense/librealsense · GitHub

Re: Light sensor on d435

YHirs1 — Mon, 15 Oct 2018 13:54:47 GMT

Hey MartyG,

Thank you for the quick replay.

I have looked on what you sent, and it is not exactly what I was looking for.

The value i'm looking for is the amount of light that D435 is exposed to. I need to get this value from a specific sensor.

which sensor can give me that value? and how can I read that value from the sensor?

many thanks,

yom

Re: Light sensor on d435

MartyG — Mon, 15 Oct 2018 14:20:18 GMT

Both the depth and color functions have exposure-related elements. You can look them up on page 61 to 63 of the 400 Series data sheet, in tables 4-12 and 4-13.

https://www.intel.com/content/dam/support/us/en/documents/emerging-technologies/intel-realsense-technology/Intel-RealSense-D400-Series-Datasheet.pdf https://www.intel.com/content/dam/support/us/en/documents/emerging-technologies/intel-realsense-technology/Intel-RealSen…

Re: Light sensor on d435

YHirs1 — Sun, 21 Oct 2018 15:35:32 GMT

I am familiar with the D400 data sheet and with the exposure-related elements.

Still, those elements use a light sensor that evaluates the amount of light around, and according to that (with a specific algorithm), the exposure and AWB parameter are being set on the RealSense app.

I am trying to understand how can I get the value from that light sensor component.

Every camera has an ambient light sensor, this link might clarify what I mean:

https://en.wikipedia.org/wiki/Ambient_light_sensor Ambient light sensor - Wikipedia

thanks

Re: Light sensor on d435

MartyG — Sun, 21 Oct 2018 16:05:21 GMT

I did extensive follow-up research to your question. Although incoming light is apparently handled by the camera's CMOS first, I could not find evidence that the camera has a light sensor component, and so may calculate the light level in some other way. The data sheet says that the CMOS chip is in the imager.

An article about the 400 Series on the Tom;s Hardware website suggested that performance in low light is related to the shutter type and lens size, with the D435's faster global shutter and larger lenses performing better in low-light conditions.

I do not know of a way to directly measure that incoming light with a value though, unfortunately.

Re: Light sensor on d435

YHirs1 — Mon, 22 Oct 2018 08:53:07 GMT

OK! Thank you!

I have looked on that article as well now and researched it a little bit more.

looks like there is another way which is common with cameras today, this method called TTL metering, stands for Through- The- Lens metering, Works with the camera's CMOS.

I don't think it's possible to get a value from that method...

Thank you anyway! you helped me a lot.

Re: Light sensor on d435

MartyG — Mon, 22 Oct 2018 08:58:18 GMT

You're very welcome. I'm glad I could be of help. Have a great week!