MATLAB Answers


How to plot a circle using contours?

Asked by Venkatessh on 26 Aug 2013

I would like to create a sequence of contours given just the location, size and brightness of the object. This is to characterize how the size and the brightness changes over time.

  • Example data:
  • # Location Size Brightness
  • 100 10 12
  • 200 15 9
  • 275 13 7 ...

Can anyone help with an example code?


You have only given one coordinate for location, but you want to plot circles? Are the "location" data radii around a common center? Is size a radius, a diameter, a distance above the counter below? Can any RGB color be chosen whose rgb2gray() matches the brightness ?

And what is "the object"? And why would you expect the object to change size and brightness over time? Are you tracking something, like a particle as it moves in time, from one frame of video to the next? Is the particle moving in one dimension so the "Location" is just the 1-D location along the axis of movement? Think about what you posted from our point of view. Post a diagram or image if you can.

Read this:

Yes, it does describe the evolution of a particle. In this context, we assume it to be circular. The size mentioned here is the diameter with the center described by the location of the particle at that instant.

The choice of color could be any but the scale should be uniform throughout the sequence.

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