Unit of Distance between two points

I would like to measure the distance between two points and I used pdist(). But, the variation is too large from the real distance. What is the unit of measurement here? Pixels?

Answer 1

[Walter Roberson]

Whatever the units were for the numbers you passed into pdist()

[Emmanuel]

I passed the x and y co=ordinates that was detected by matlab. Can you tell me as to in which unit were the co-ordinateds tracked?

Thanks.