Since you have all of the object positions (I assume you know the sequential order of each position as well), you can use Bresenham's line drawing algorithm. Here is a file-exchange submission. This is a well implemented algorithm but the author forgot to terminate a couple of lines with ';', so be sure to add those unless you want tons of stuff printed to the command window. https://www.mathworks.com/matlabcentral/fileexchange/28190-bresenham-optimized-for-matlab
To do this, first get your position coordinates as the (x,y) pixel indices. Then, for each iteration of the sequence (from 1 -> 2, from 2 -> 3, from 3 -> 4, etc.), just call the Breshenam algorithm to generate the list of x and y coordinates associated with the line between each set of two points. For instance, your workflow would go something like this:
Make a red line between points, given two locations '(x1,y1)' and '(x2,y2)':
>> [x y]=bresenham(x1,y1,x2,y2);
>> for i = 1:length(x)
>> Iin(y(i),x(i),1) = 255;
>> Iin(y(i),x(i),2) = 0;
>> Iin(y(i),x(i),3) = 0;
>> end
