strong textHi all,
I am trying to create a basic version of the vOICe (http://www.seeingwithsound.com) to run on Linux and devices similar to the raspberry pi. This involves writing C code. The last time I did anything in C was 1994 or perhaps 1996. Any how, I have most of the stuff worked out. There is basic soundscape generation code at http://www.seeingwithsound.com. That code works on Linux.
I am using the opencv library to capture images from a webcam on Linux. I am unable to integrate opencv's output with the code of the vOICe. The vOICe expects pixel coordinates as numbers. I need to replace the hard coded image coordinates with the output from a webcam. I am not sure how openccv gives said coordinates. Yes, I did search and found the answer but I cannot understand the data type conversions involved. The answer is at the opencv faq. http://opencv.willowgarage.com/wiki/faq#Howtoaccessimagepixels
I am pasting the opencv code and then the code of the vOICe. Note: If extracting the code from this message becomes a problem, I have the 2 files in dropbox. Openn cv code: https://dl.dropboxusercontent.com/u/3688386/ot.c the link to the code for the vOICe https://dl.dropboxusercontent.com/u/3688386/i2s.c
//text of opencv code
include <stdio.h>
include <stdlib.h>
include "stdafx.h"
include <math.h>
include <cv.h>
include <highgui.h>
void main(int argc,char argv[]) { int c; IplImage color_img; CvCapture* cv_cap = cvCaptureFromCAM(0); color_img = cvQueryFrame(cv_cap); // get frame
int nl= color_img->height;
int nc= color_img->width * color_img->nChannels;
unsigned char *data= reinterpret_cast<unsigned char *>(color_img->imageData);
cvNamedWindow("Video",0); // create window for(;;) { if(color_img != 0) cvShowImage("Video", color_img); // show frame c = cvWaitKey(10); // wait 10 ms or for key stroke if(c == 27) break; // if ESC, break and quit } /* clean up */ cvReleaseCapture( &cv_cap ); cvDestroyWindow("Video"); }
//The code of the vOICe /* Simple C program for .wav soundscape generation. (C) P.B.L. Meijer 1996 */
define FNAME "arti1.wav"
define N 64 /* Resolution, i.e., # rows and columns */
define FL 500 /* Lowest frequency (Hz) in visual sound */
define FH 5000 /* Highest frequency (Hz) */
define FS 20000 /* Sample frequency (Hz) */
define T 1.05 /* Image to sound conversion time (s) */
define D 1 /* Linear|Exponential=0|1 distribution */
include <stdio.h>
include <stdlib.h>
include <math.h>
define C_ALLOC(number, type) ((type *) calloc((number),sizeof(type)) )
define TwoPi 6.283185307179586476925287
define WHITE 1.00
define DGREY 0.25
define BLACK 0.00
FILE fp; unsigned long ir=0L, ia=9301L, ic=49297L, im=233280L; void wi(unsigned int i) { int b1,b0; b0=i%256; b1=(i-b0)/256; putc(b0,fp); putc(b1,fp); } void wl(long l) { unsigned int i1,i0; i0=l%65536L; i1=(l-i0)/65536L; wi(i0); wi(i1); } double rnd(void){ ir = (iria+ic) % im; return ir / (1.0*im); }
int main(int argc, char argv[]) { int i, j, b, d = D; long k = 0L, ns = (long) (FS * T), m = ns / N; double *A, t, dt = 1.0 / FS, w, *phi0, s, y, yp, z, tau1, tau2, scale = 0.5/sqrt(N); w = C_ALLOC(N, double); phi0 = C_ALLOC(N, double); A = C_ALLOC(N, double *); for (i=0; i<n; i++)="" a[i]="C_ALLOC(N," double);="" <="" em=""> N x N pixel matrix */
/* Set hard-coded image: diagonal, filled rectangle, 3 horizontal lines */ for (j= 0; j< N; j++) for (i=0; i< N; i++) if (i==j) A[i][j] = WHITE; else A[i][j] = BLACK; for (j=39; j<60; j++) for (i=9; i<27; i++) if (j<47) A[i][j] = DGREY; else A[i][j] = WHITE; for (j= 4; j< 8; j++) A[40][j] = WHITE; for (j= 8; j<12; j++) A[31][j] = WHITE; for (j=12; j<16; j++) A[40][j] = WHITE;
/* Set lin|exp (0|1) frequency distribution and random initial phase / if (d) for (i=0; i<n; i++)="" w[i]="TwoPi" *="" fl="" *="" pow(1.0<="" em=""> FH/FL,1.0*i/(N-1)); else for (i=0; i<n; i++)="" w[i]="TwoPi" *="" fl="" +="" twopi="" *="" (fh-fl)="" *i="" (n-1)="" ;="" for="" (i="0;" i<n;="" i++)="" phi0[i]="TwoPi" *="" rnd();<="" p="">
/* Write 8-bit .wav visual sound file, using rectangular time window / fp = fopen(FNAME,"wb"); fprintf(fp,"RIFF"); wl(ns+36L); fprintf(fp,"WAVEfmt "); wl(16L); wi(1); wi(1); wl(0L+FS); wl(0L+FS); wi(1); wi(8); fprintf(fp,"data"); wl(ns); tau1 = 0.5 / w[N-1]; tau2 = 0.25 * tau1tau1; y = z = 0.0; while (k < ns) { /* Not optimized for speed (or anything else) */ s = 0.0; t = k * dt; j = k / m; if (j>N-1) j=N-1; for (i=0; i<n; i++)="" s="" +="A[i][j]" *="" sin(w[i]="" *="" t="" +="" phi0[i]);="" if="" (k="" <="" ns="" (5*n))="" s="(2.0*rnd()-1.0)" scale;="" *="" "click"="" *="" yp="y;" y="tau1/dt" +="" tau2="" (dt*dt);="" y="(s" +="" y="" *="" yp="" +="" tau2="" dt="" *="" z)="" (1.0="" +="" y);="" z="(y" -="" yp)="" dt;="" b="128" +="" (int)="" (scale="" *="" 128="" *="" y);="" *="" y="2nd" order="" filtered="" s="" *="" if="" (b="" >="" 255)="" b="255;" if="" (b="" <="" 0)="" b="0;" putc(b,fp);="" k++;="" }="" if="" ((ceil(ns="" 2))!="(ns/2))" putc(0,fp);="" fclose(fp);="" return(0);="" }<="" p="">
Pranav
