AWR1843BOOST: Occupancy Detection and Vital Signs: Repeated Question

Can any person help me, I am a little bit confused from vital signs breathing and inhale rate also unit of displacement which is 'au' 

Hi,

My apologies that the ball got dropped here, allow me to reach out to the related parties so that we can help get to the bottom of this.

Best Regards,
Alec

Hello Alec,

In Driver vital signs example (Automotive toolbox 3.3.0), it's mentioned that breathing rate and heart rate are made based on the confidence metric from different spectral estimation methods, page 8. 

https://dev.ti.com/tirex/explore/node?node=AAZ.3LdjgB9ICpyXqcY3zA__AocYeEd__LATEST

Q1. Is there difference in (breathing rate-heart rate) between Driver vital signs example code and Occupancy and vital signs example?

Q2. Why phase of Inhale rate 1 - 2 and Heart rate 1 - 2 didn't change when person is detected. In above image it appears one person on the right of radar, and it seems not affect in phase!

I traced the data comes from Radar into MATLAB and I found the "extractedValue" didn't get affect whether there is person detected or not!!

Basically my main target is to test Occupancy and vital signs example code.

Q3. Is I want to know what's "a.u" of displacement stands for? 

Thanks,

Mostafa

Hi Mostafa,

One of the first differences you will notice between the two demos is that their mounting recommendations are quite different. The occupancy + vital signs demo is intended to be placed much farther away in order to capture both zones. If you want to better understand the differences between these projects, it may be beneficial to think of it as two separate pieces. One part is the processing on the device, and the other part is the processing done by the host with the visualizer. To understand the on chip processing, you can look at the output format coming from the demos and see any differences there. Then you can look at the visualizers and their provided source to better understand the differences in their processing. Please take some time to review this while I get the answers to some of your specific questions.

Best Regards,
Alec

Hello,

Alec May said:

One part is the processing on the device, and the other part is the processing done by the host with the visualizer

Do mean in (Vehicle Occupancy Detection and Vital Signs project) that vital signs calculation splitted between the device and the visualizer? if so, where is phase of inhale and breathing rate + displacement is implements, because the six plots doesn't make sense

My thought is that the Phase of Inhale and Breathing is effect of Inhale and exhale of human, so when no human detected inside one of two zones the phases and displacement will be straight line. Is that Correct?

My second question what's (a.u) mentioned in image above stands for?

Thanks

Mostafa

Mostafa,

I looked at this project specifically, and I believe all the calculations that you are interested in are done in the DSS project (the DSP subsytem). I would suggest that you take some time to read and step through this code in order to better understand the calculations done there. I believe that you will specifically be interested in the VS_OUTPUT_HEART_BREATHING_RATES packet. 

In regards to your inquiry about a.u, I have reached out to the party that originally designed this GUI in order to clear that up, as this is not a standard unit that we use.

Best Regards,
Alec

Hello Alec,

I have viewed this session: https://training.ti.com/intro-mmwave-sensing-fmcw-radars-module-2-phase-if-signal?context=1128486-1139153-1128543

Regarding your last reply

Alec May said:

this is the relationship between phase in radians and displacements in meter.

Q1. Even when there is no person on front of radar it the 2 displacement plot, inhale phase and breathing phase is changing as showed in the figure above. How do you explain that?

In static environment the phase shouldn't change in phase neither location of range FFT, is that correct?

Alec May said:

That being said, the reason I had the displacement as “arbitrary unit (a.u)” rather than a physical unit e.g. mm

Q2. can I convert from this arbitrary unit to mm unit inside Matlab?

Q3. Is the only reasonable thing in the visualizer are the Inhale rate and Breathing rate correct?

Thanks,

Mostafa

Hello Alec, 

Thanks for reply.

Alec May said:

I believe you would see your expected straight line if you were to test in an environment without noise such as an anechoic chamber.

I will test that and be back to you.

Q1. Could you give me a hint where to start to be able to calculate the mm unit from this arbitrary unit? If the phase of Inhale and breathing is just the phase of signal so it should be processed by range FFT and doppler FFT, correct?

Same to the Displacement, it's the also the phase of range-FFT signal, correct?

Thanks,

Mostafa