How can I calculate the size of an object from a set of photos with no reference point?

I need to calculate the different aspect of an object in a photo where it is the sole thing in frame. I know its average total length but not what camera/distance/zoom was used.

Is it possible to calculate its different aspects solely from a small range of images, given that the object is at an angle?

Answer 1

[Image Analyst]

If you know the total length of some thing in the image, then you can compute the number of cm per pixel and then you can measure the distance between any two points assuming they're in close to the same optical plane of your reference measurement. However another image, like a close-up, will have a different value for cm per pixel and you can't use the same spatial calibration value as you got from the other image. You'd need a new know calibration distance in the new image.

See attached spatial calibration demo.

I don't know what a "different aspect" is in the context you've used it so you'd need to define that for us.