How to find the physical distance in real word between two places or points in an image?

Respected Sir/Madam,

Please send me the related code or work for the below problem statement.

Problem:By clicking on any two points on image (Image should be a map of a city), it should give me the physical distance(in terms of meters or kilo meters) between the two points.

1.Here points corresponds to coordinates of any two places of the city or a map

2.Once we run the program using Matlab, it should show me the image of suitable resolution.

3.How to select two points on image by just clicking on that image?

4.We need to get the coordinates of pixels and find the distance between them, and then convert the distance between pixel to the physical distance like kilo meters or meters.

Finally it should help us to know the distance between two places by just clicking on any two places.

Please help me. I'm in very need of it. Please send as early as possible.

Thank you.

[Guillaume]

Why your question is not urgent

How do I get help on homework questions

Answer 1

[Image Analyst]

That's exactly what my spatial calibration demo (attached) does.

[AVINASH]

I'm very much thankful to you analyst. I'm really appreciating your work. But I had a doubt on the spatial calibration. Here it is,

1. Suppose if we consider the "cameraman" image, which is given in the menu of demo, and I wanted to know his height in terms of feet or meters. In such a case how to do the calibration, when it is asking like _ choose the real world units and enter the distance in that units. _

2. In another case, that too in the case of "coins" image, the distance between any to coins usually may be in terms centimeters, in such a case how to get the actual distance that exists there.

Since I'm not getting the distance that is actually present. Please I'm kindly requesting you to help me out on how to give the values while doing the spatial calibration in such scenarios or situations.

Thank you.

[Image Analyst]

You have to have something to measure first that is of known dimensions (lengths, distances). For example if I had an image of the moon, how do I know it's the real moon from through a telescope instead of a poster on the wall? Well you have to measure some known distance, for example a ruler on the wall next to your poster, or the diameter of the moon if you know it's the real one. Once you enter that known distance then you can go on to measure any arbitrary distances or areas in the image.