microsoft / Azure-Kinect-Sensor-SDK

A cross platform (Linux and Windows) user mode SDK to read data from your Azure Kinect device.
https://Azure.com/Kinect
MIT License
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Azure Kinect modulation frequency and range ambiguity #1807

Open JeffR1992 opened 2 years ago

JeffR1992 commented 2 years ago

Is it possible to change the Azure Kinect's modulation frequency using the SDK, or is this value hardcoded?

In addition to this, since the Azure Kinect is an indirect ToF sensor, I wanted to ask how the sensor is able to deal with the common "range ambiguity" issue that occurs due to phase wrapping. After doing a few searches online it seems like the Azure Kinect might be operating at a default modulation frequency of 320 MHz, which would imply that the first range ambiguity should occur at a very low range of 0.46 meters. However, this is clearly not the case as I haven't noticed any range ambiguities in any data that I've seen while using the sensor. Any information would be appreciated, thanks very much.

conatsera commented 2 years ago

The depth acquisition process is handled in the proprietary depthengine dll module. Beyond refresh rate and depth mode, it's methodology can't be modified by the SDK.

As for the question of range ambiguity, while not directly stated, it likely continues to use the multi frequency method employed by previous ToF sensors. The sensor's white paper states an average system modulation frequency of 200MHz with a range from 10MHz to 320MHz.

https://ieeexplore.ieee.org/document/8310200

On Tue, Jul 19, 2022, 11:29 PM JeffR1992 @.***> wrote:

Is it possible to change the Azure Kinect's modulation frequency using the SDK, or is this value hardcoded?

In addition to this, since the Azure Kinect is an indirect ToF sensor, I wanted to ask how the sensor is able to deal with the common "range ambiguity" issue that occurs due to phase wrapping. After doing a few searches online it seems like the Azure Kinect might be operating at a default modulation frequency of 320 MHz, which would imply that the first range ambiguity should occur at a very low range of 0.46 meters. However, this is clearly not the case as I haven't noticed any range ambiguities in any data that I've seen while using the sensor. Any information would be appreciated, thanks very much.

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