[DEV] add base of delay and sum

lutinParseSubFolders.txt

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+tools/beamforming

tools/beamforming/beamPattern.cpp

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+#include <stdio.h>
+#include <math.h>
+// http://www.labbookpages.co.uk/audio/beamforming/delaySum.html
+#define ANGLE_RESOLUTION 500    // Number of angle points to calculate
+
+int main(void) {
+	int numElements = 4; // Number of array elements
+	double spacing = 0.2; // Element separation in metres
+	double freq = 1000.0; // Signal frequency in Hz 
+	double speedSound = 343.0; // m/s
+	// Iterate through arrival angle points
+	for (int32_t aaa=0; aaa<ANGLE_RESOLUTION; aaa++) {
+		// Calculate the planewave arrival angle
+		double angle = -90.0 + 180.0 * double(aaa) / double(ANGLE_RESOLUTION-1.0);
+		double angleRad = M_PI * double(angle) / 180.0;
+		double realSum = 0;
+		double imagSum = 0;
+		// Iterate through array elements
+		for (int32_t iii=0; iii<numElements; iii++) {
+			// Calculate element position and wavefront delay
+			double position = iii * spacing;
+			double delay = position * sin(angleRad) / speedSound;
+			// Add Wave
+			realSum += cos(2.0 * M_PI * freq * delay);
+			imagSum += sin(2.0 * M_PI * freq * delay);
+		}
+		double output = sqrt(realSum * realSum + imagSum * imagSum) / numElements;
+		double logOutput = 20 * log10(output);
+		if (logOutput < -50) {
+			logOutput = -50;
+		}
+		printf("%d %f %f %f %f\n", a, angle, angleRad, output, logOutput);
+	}
+	return 0;
+}
+
+

tools/beamforming/beamPattern.gnuplot

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+reset
+unset key
+set xlabel "Arrival Angle (degrees)" font "arial,12"
+set ylabel "Gain (dB)" font "arial,12"
+set grid lc rgbcolor "#BBBBBB"
+plot 'beamPattern.dat' u 2:5 w l

tools/beamforming/freqResp.cpp

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+#include <stdio.h>
+#include <math.h>
+// http://www.labbookpages.co.uk/audio/beamforming/delaySum.html
+
+// Number of freq points to calculate
+#define FREQ_RESOLUTION 500
+// Number of angle points to calculate
+#define ANGLE_RESOLUTION 500
+
+int main(void) {
+	int numElements = 4; // Number of array elements
+	double spacing = 0.2; // Element separation in metre
+	double speedSound = 343.0; // m/s
+	// Iterate through arrival angle points
+	for (int32_t fff=0; fff<FREQ_RESOLUTION; ++fff) {
+		double freq = 10000.0 * double(fff) / double(FREQ_RESOLUTION-1);
+		for (int32_t aaa=0; aaa<ANGLE_RESOLUTION; ++aaa) {
+			// Calculate the planewave arrival angle
+			double angle = -90.0 + 180.0 * double(aaa) / double(ANGLE_RESOLUTION-1);
+			double angleRad = M_PI * double(angle) / 180.0;
+			double realSum = 0;
+			double imagSum = 0;
+			// Iterate through array elements
+			for (iii=0; iii<numElements; ++iii) {
+				// Calculate element position and wavefront delay
+				double position = double(iii) * spacing;
+				double delay = position * sin(angleRad) / speedSound;
+				// Add Wave
+				realSum += cos(2.0 * M_PI * freq * delay);
+				imagSum += sin(2.0 * M_PI * freq * delay);
+			}
+			double output = sqrt(realSum * realSum + imagSum * imagSum) / numElements;
+			double logOutput = 20.0 * log10(output);
+			if (logOutput < -50.0) {
+				logOutput = -50.0;
+			}
+			printf("%f %f %f\n", angle, freq, logOutput);
+		}
+		printf("\n");
+	}
+	return 0;
+}

tools/beamforming/freqResp.gnuplot

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+reset
+set xlabel "Arrival Angle (degrees)" font "arial,8"
+set ylabel "Frequency (Hz)" font "arial,8"
+set zlabel "Gain (dB)" font "arial,8"
+set grid lc rgbcolor "#BBBBBB"
+set xrange[-90:90]
+set yrange[0:10000]
+set zrange[-40:0]
+unset key
+set view 30,56,0.98
+splot 'freqResp.dat' u 1:2:3 with pm3d

tools/beamforming/polar.gnuplot

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+reset
+set angles degrees
+set polar
+set grid polar 30 lc rgbcolor "#999999"
+unset border
+unset param
+set size ratio 1 1,1
+set xtics axis nomirror -50,10
+unset ytics
+unset key
+set style data line
+set xrange[-50:50]
+set yrange[-50:50]
+set rrange[-50:0]
+set label 1 "0°" at graph 1.01,0.5 front
+set label 2 "180°" at graph -0.01,0.5 right front
+set label 3 "-90°" at graph 0.5,-0.03 center front
+set label 4 "90°" at graph 0.5,1.03 center front
+plot 'beamPattern.dat' u 2:5