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AWR1642: Frames required for a stable detection

Part Number: AWR1642

Hello everyone,

We are currently testing our AWR1642 radar for ACC application and came across some difficulty while detecting objects in motion. What we have observed that sometimes , even though when there are no objects in our ROI ( majorly the front area covering  between 85-95 degrees) we see objects pop up for a frame or two and then they are back to where they originally should be. Also we have experienced many noisy object detection in cases where the number of objects is larger.

Our radar configuration is as follows :

% ***************************************************************
% Frequency:77
% Platform:xWR16xx
% Scene Classifier:best_range
% Azimuth Resolution(deg):15
% Range Resolution(m):0.244
% Maximum unambiguous Range(m):50
% Maximum Radial Velocity(m/s):1
% Radial velocity resolution(m/s):0.13
% Frame Duration(msec):50
% ***************************************************************
sensorStop
flushCfg
dfeDataOutputMode 1
channelCfg 15 3 0
adcCfg 2 1
adcbufCfg 0 0 1 1
profileCfg 0 77 2 5.30 52.68 0 0 15 1 256 6250 0 0 40
chirpCfg 0 0 0 0 0 0 0 1
chirpCfg 1 1 0 0 0 0 0 2
frameCfg 0 1 16 0 50 1 0
guiMonitor 1 0 0 0 0 0
cfarCfg 0 0 8 4 4 0 5120
cfarCfg 1 0 4 2 3 0 5120
peakGrouping 1 1 1 1 255
multiObjBeamForming 1 0.5
sensorStart

So are there certain number of frames required to detect the object properly ? And do they by default place the object in the center of the FOV ? Furthermore, is there any way we could get rid of these noisy detection objects ?

Thanks  

  • Hi Amol

    Did you try the suggestions from e2e.ti.com/.../615795 Also, if possible can you capture a video of these false detections and share it?

    Regards,
    Anil
  • Hi Anil,

    We have already tried the suggestions provided in the thread which you directed me to. Also about your suggestion regarding a video, I am attaching the following video. In this video the configurations are as I described before. The .bin file we used to here is the original mmw-demo .bin file.

    You can observe a bunch of things in this video which depict false positives , too many points under the bridge , points popping up inside our ROI ( Shown using red parallel lines on the visualizer ). I am sorry about the rainy scenario in the video as we recorded it today ans its been raining here.

    Looking forward to your inputs based on our observations. 

    Thanks

  • Hi Amol,

    Thanks for the video. Could you try another capture with the configuration that I've provided below? I have increased the number of chirps per frame (from 16 to 128), which should improve the SNR.  I have increased the SNR threshold for CFAR from its previous value (about 15 dB)) to about 18 dB. I have also disabled the multi-peak option, and removed the MIMO configuration. Each of these options increase the SNR, and reduce the possibility of false detections.

    Since TI's EVM has an elevation FoV of about 10 degrees, objects above and below the radar will be detected. For an ACC application, you should redesign the antenna to have much lower elevation FoV ( say 1 degree or lesser). 

    Modified configuration begins below :   

    sensorStop

    flushCfg

    dfeDataOutputMode 1

    channelCfg 15 3 0

    adcCfg 2 1

    adcbufCfg 0 0 1 1

    profileCfg 0 77 2 5.30 52.68 0 0 15 1 256 6250 0 0 40

    chirpCfg 0 0 0 0 0 0 0 1

    frameCfg 0 0 128 0 50 1 0

    guiMonitor 1 0 0 0 0 0

    cfarCfg 0 0 8 4 4 0 6144

    cfarCfg 1 0 8 4 4 0 6144

    peakGrouping 1 1 1 1 224

    multiObjBeamForming 0 0.5

    sensorStart

    multiObjBeamForming 0 0.5

    Regards,

    Anil

  • Hi Anil,

    Thanks for the response. I will try the configuration you suggested. In addition to that how do we change the angle of antenna ? I am afraid that it could be a hardware modification and not a software one .Correct me if I am wrong.

    Thanks
  • Hi Anil,

    We implemented the configuration which you have recommended over here. Although your recommendation helped to reduce noisy detection it is still not sufficient to enable better detection. in the following video you can observe that there are still noisy points popping up in the ROI which is a big obstruction for our desired ACC application. Could you please suggest more methods to overcome this issue? We are also trying some tweaks on the configuration and would let you know if we get results better than what we have right now.

    Thanks 

  • Hi Amol. 

    I watched the video, and I don't see spurious detections. Every object detected seems to correspond to an object in the scene. Could you freeze a frame with the problematic detection and publish it? 

    Also, I noticed that you've set the range depth to about 10 meters, even though the configuration allows for upto 50m. Is there a reason for this? 


    Regards,

    Anil

  • Hi Anil,


    Thank you for watching the video. I think if you closely watch the video again, there are some noisy points that you can observe. For instance notice at 0:34 that despite the vehicles being on the left side you can still see some objects being detected in the center when there were o objects at all, also 1:10 onwards, you can see that there are points in the very close range (<1 m) which are visible on the visualizer.

    One more thing, the range depth is at 50m in the configuration. How did you think that it was 10? The visualizer shows the arc only till 10m always.

    Also finally, we are transmitting the detected objects in to our C code by using a javascript file that finds them on the visualizer and sends them to the C code using socket io , when we do this we can see points in close range ( 2-7 m) inside the ROI ( 1m on both left ad right from the center) whenever oncoming cars from the left pass though our car. This makes our ACC system think that there is a car in the center lane and that lowers the efficiency of our application. Could you suggest some modifications for this ? I am willing to provide you more information/ multimedia if required.

    Also in response to your configurations, we tried increasing the SNR ratio which did not really make much difference on the detections. However, when we increased the threshold values more ( 10000) we were able to eliminate spurious detections but that also led to loss of regular detections. 



    Thanks.

  • Hi Amol,

    I see the issue.

    There are a number of options to reduce those close in reflections.

    1. Collect ADC data of the scene and check why these detections happen. It is likely to be clutter (i.e. reflections from the road). If that is the case, the best option would be redesign the antenna (a physical change to the board) so that the elevation FoV is reduced.

    2. You can check the 'signal power' of the detected object, and based on its distance to the car, decide whether to allow it. The variable 'peakVal' in the visualizer source is an estimate of the 'signal power'. Check what the difference is between a valid close object, and the clutter floor (i.e the road), and set a threshold based on the distance of the object, and the 'signal power'. For example if the distance is less than 5 meters, the peakVal should be atleast x, between 5 meters and 10 meters, it should be at least y, etc. You would need to experiment and find thresholds that work for you. This would be an additional check on the CFAR-CA algorithm running on the device. Note that you can implement the above change on the device, or on the visualizer source.

    3. Implement some kind of tracking algorithm (say an extended kalman filter) that would check for consistency of objects between frames. TI is working on tracking algorithms specifically for Radar, and these would be added to SDK in the near future (early 2018).

    Regards,
    Anil