Creating a timelapsed composite video with plots and webcam images

From Lehigh RTMD Wiki

Saving the plot images from MATLAB

Below is sample code for creating a set of plot images based on an x and y history. This assumes that MATLAB array 'xval' contains the x values and array 'yval' contains the y values. Also, they both must have the same number of rows. The images will be created in the working directory.

i = 1;
sizeof = size(xval);
xmin = -0.04;
xmax = 0.04;
ymin = -1.0;
ymax = 1.0;

while (i <= sizeof(1))
    plot(xval(1:i),yval(1:i),'r',xval(i:i),yval(i:i),'--b>','MarkerSize',5,'MarkerFaceColor','b');
    xlabel('Rotation (rads)');
    ylabel('Normalized Moment, M/Mpn');
    title('Normalized Moment vs Rotation');
    axis([xmin xmax ymin ymax]);
    grid on;
    filename = ['images/graph' sprintf('%06',i)];
    print('-djpeg',filename);    
    i = i + 1;
end

C code for creating composite images

Below is example C code for batch processing the composition with Imagemagick. A required file, "bg.jpg", should be the background sized to the necessary dimensions for MJPEG (ie, 1024x768);

#include <stdio.h>
#include <stdlib.h>

int main (int argc, char *argv[])
{
  int i;
  int numfiles;
  int numplots;
  char buf[1000];
  char* imagemagickpath = "C:\\Progra~1\\IMAGEM~1.6-Q\\convert";
  FILE *f;     

  // Pass in the number of files to use in the composition
  numfiles = atoi(argv[1]);

  // For loop goes through each set of images and creates the composite image
  for (i = 1; i <= numfiles; i++) {
   printf("[Composite] : Image %i/%i\n",i,numfiles);
   // Resize the plot
   sprintf(buf,"%s plots\\image%06d.jpg -resize 500 -quality 100 tempvid1.jpg",imagemagickpath,i);
   system (buf);

   // Resize the webcam image
   sprintf(buf,"%s webcam\\image%06d.jpg -resize 500 -quality 100 tempvid2.jpg",imagemagickpath,i);
   system (buf);

   // Add the plot to the west portion of the background
   sprintf(buf,"%s -quality 100 -compose Over -gravity west tempvid1.jpg bg.jpg new.jpg",imagemagickpath);
   system (buf);

   // Add the image to the east portion of the background
   sprintf(buf,"%s -quality 100 -compose Over -gravity east tempvid2.jpg new.jpg output\\image%06d.jpg",imagemagickpath,i);
   system (buf);	  
  }		  

  // Cleanup
  system ("del tempvid1.png tempvid2.png new.png");

  return 0;
}

Then see Creating timelapsed webcam video on how to create the video file.