HOW TO FIND THE VELOCITY OF AN IMAGE?

Sir,

i have 26 images. i need to find the velocity of that images. how would i been find that velocity explain in coding means its been more useful for me. in matlab its there any inbuilt funcution for find velocity

[David Sanchez]

what do you mean by "velocity of an image"? The velocity of objects present in the images?

[ajith]

in my image set there is a blood flow so i need to find the velocity of blood flow.

Answer 1

[David Sanchez]

You can not calculate the speed of an object within an image unless you know the length of the objects and the time taken by the objects to go from one position to the next. The equation is simple.

Velocity = distance/time; % as you surely know

If you know the distance travelled by your cells and the time taken in the process, you can obtain the velocity.

[ajith]

but sir how to find velocity using pixels

[David Sanchez]

you have to know the equivalence between pixel and mm. If you are working with blood stream, it will definitively be difficult to know. Do you know the size of your cells (in mm)? If so, measure their size in pixels and extrapolate to the distance travelled by the cells. In those small scales, the time taken will be very short and the precision of your measurement will be affected.

[ajith]

i use horn and shunk method http://www.mathworks.in/help/vision/ref/vision.opticalflowclass.html in this specifies the velocity output i completed to find the optical flow (u,v) i need to find the velocity output how would i find the result.