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Rev 647 Rev 649
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#include <math.h>
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#include <math.h>
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#include <fftw3.h>
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#include <fftw3.h>
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#define SOUND_SPEED	340.0	// sound speed in air in metrs per second
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#define SOUND_SPEED	340.0	// sound speed in air in metrs per second
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#define MAX_RANGE	10.0	// maximal working radius in meters
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#define MAX_RANGE	10.0	// maximal working radius in meters
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#define APERTURE	0.2	// distance between microphones
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#define Xl	-0.1		// microphones position
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#define Xr	0.1
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static char *device = "plughw:0,0";			/* playback device */
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static char *device = "plughw:0,0";			/* playback device */
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static snd_pcm_format_t format = SND_PCM_FORMAT_S16;	/* sample format */
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static snd_pcm_format_t format = SND_PCM_FORMAT_S16;	/* sample format */
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static unsigned int rate = 96000;			/* stream rate */
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static unsigned int rate = 96000;			/* stream rate */
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static unsigned int buffer_time = 2 * (MAX_RANGE / SOUND_SPEED * 1e6);		/* ring buffer length in us */
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static unsigned int buffer_time = 2 * (MAX_RANGE / SOUND_SPEED * 1e6);		/* ring buffer length in us */
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    chirp = calloc(2*period_size, sizeof(short));
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    chirp = calloc(2*period_size, sizeof(short));
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    signal = malloc(2*period_size * sizeof(short));
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    signal = malloc(2*period_size * sizeof(short));
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    echo_map = malloc(3*period_size*period_size * sizeof(float));   // Array to store two dimensional image of echos
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    echo_map = malloc(3*period_size*period_size * sizeof(float));   // Array to store two dimensional image of echos
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    if (echo_map == NULL) printf("Can't allocate enought memory");
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    if (echo_map == NULL) printf("Can't allocate enought memory");
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    k = SOUND_SPEED/rate;
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    k = SOUND_SPEED/rate; // normalising constant
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// generate ping pattern
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// generate ping pattern
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    chirp_size = linear_windowed_chirp(chirp);
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    chirp_size = linear_windowed_chirp(chirp);
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    frequency_bins = chirp_size / 2 + 1;
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    frequency_bins = chirp_size / 2 + 1;
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    df = (double) rate / (double) chirp_size;
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    df = (double) rate / (double) chirp_size;
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	{
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	{
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		a=k*i;
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		a=k*i;
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		for(j=0;j < period_size; j+=10)
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		for(j=0;j < period_size; j+=10)
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		{
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		{
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			b=k*j;
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			b=k*j;
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			echo_map[m]=(a*a-b*b+APERTURE*APERTURE)/(2*APERTURE);
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			echo_map[m]=(-a*a+b*b+Xl*Xl+Xr*Xr)/(2*Xl-2*Xr);
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			echo_map[m+1]=sqrt((a-b-APERTURE)*(a+b-APERTURE)*(a-b+APERTURE)*(a+b+APERTURE))/(2*r);
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			echo_map[m+1]=sqrt((a-b-Xl-Xr)*(a+b+Xl+Xr)*(a-b-Xl+Xr)*(a-b-Xl+Xr)*(a+b-Xl+Xr))/(-2*(Xl-Xr));
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			echo_map[m+2]=correlationl[i]*correlationr[j];
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			echo_map[m+2]=correlationl[i]*correlationr[j];
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			m+=3;
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			m+=3;
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		}
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		}
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	}
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	}
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    printf("Searching echos\n");
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    printf("Searching echos\n");
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    }
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    }
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    fclose(out);
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    fclose(out);
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    j=0;
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    j=0;
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    out=fopen("/tmp/plane_cut.txt","w"); // writes plane cut - e.g. density map to file
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    out=fopen("/tmp/plane_cut.txt","w"); // writes plane cut - e.g. density map to file
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    for (i=0;i < period_size*period_size; i++)
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    for (i=0;i < period_size*period_size/100; i++)
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    {
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    {
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	fprintf(out,"%3.3f %3.3f %3.3f\n", echo_map[j], echo_map[j+1], echo_map[j+2]);
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	fprintf(out,"%3.3f %3.3f %3.3f\n", echo_map[j], echo_map[j+1], echo_map[j+2]);
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	j+=3;
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	j+=3;
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    }
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    }
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    fclose(out);
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    fclose(out);