i've asked a basic question about this demo and thanks to @JohnH reply. but i still not clear about the details of that math formula for calculating weightedSum.
first about the rcs:
there is a for loop in main.c:
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for (rangeBinIndex = rangeBinStartIndex; rangeBinIndex < rangeBinEndIndex; rangeBinIndex++) {
// Points towards the real part of the current range-bin i.e. rangeBinIndex
tempIndex = (uint16_t *) tempPtr;
obj->rangeProfileCplx[2 * (rangeBinIndex - rangeBinStartIndex)] = *tempIndex;
temp_real = (int16_t) * tempIndex;
// Points towards the imaginary part of the current range-bin i.e. rangeBinIndex
tempIndex++;
obj->rangeProfileCplx[2 * (rangeBinIndex - rangeBinStartIndex) + 1] = *tempIndex;
temp_imag = (int16_t) * tempIndex;
absVal = (float) temp_real * (float) temp_real + (float) temp_imag * (float) temp_imag;
if (absVal > maxVal)
{
maxVal = absVal;
rangeBinMax = rangeBinIndex;
}
if (count == 1) // Finds the max Range Bin every 128th Frame
{
rangeBinPhase = rangeBinMax;
}
if (rangeBinIndex == (rangeBinPhase))。
phase = atan2(temp_imag, temp_real);
}
// Points towards the next range-bin
tempPtr += obj->numChirpsPerFrame * obj->numVirtualAntennas;
} // For Loop ends
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i searched some knowedge about RCS, but i don't understand why it calculates like this in this situation: in every radar bin iteration, absVal = real^2 + imag^2. what physical meaning does it stand for?
and why we only choose the largest absVal sqrt as RCSvalue?
second: the first respondent said that outSumEnergyPhaseWfm represent "movement". In the program it's related with outputFilterPhase, but i don't understand what this variable means, or what the following function calculate for:
outputFilterPhase = filter_IIR_BiquadCascade(phaseUsedComputation, obj->pFilterCoefs, obj->pScaleVals, pDelay, IIR_FILTER_NUM_STAGES);
i am confused about the third function as well:
confidenceMetic = computeConfidenceMetric(obj->phaseSpectrum, PHASE_FFT_SIZE / 4, obj->freqIncrement_Hz, maxIndexSpect, 0.2);
do they require knowledge on certain aspect in radar field or understanding on certain function in mmWave SDK?
appreciate much if my problems can be solved
Regards,
Ding
