[How to] Calculate Resolution Of An Image

In Physics AS, it is important to know how to work out the resolution of a given image. The resolution is…

The size, in real life, of one pixel or real life length / no. of pixels

For this reason, it is usually measured in metres per pixel.

Let’s have an example and calculate the resolution of the following picture of the River Thames:
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You will have to estimate the size of the image and therefore how many metres of ‘real life’ it is showing unless told. For the case of the River Thames, I have estimated the width of the given part of the river is 250 metres. On the picture, this is represented by 20 pixels (for that, I just added them up). Now, remembering the equation for working out the resolution of a image:

We have everything to work out the resolution of the above image of the Thames. 250 / 20 given us a resolution of 12.5 metres per pixel.
It is important to remeber that anything smaller than 12.5 metres you will not be able to see.
If you are revising Physics Topics, please have a look at other articles I have done on Physics you may be interested in.