For a project I'm creating a program that must analyse a database of images to define average ratios for certain parts of the face (i.e. distance between eyes, distance from nose to chin etc.). I've ran into the problem where I can find distances between these points, however each subject (image) is of differing lengths from the camera and thus the ratios will be very distorted. How would it be possible to find these ratios given some kind of scale or set of two points that I can use so that the distances I take are relative to the size of the head and not the image itself? Currently I'm working off the two extreme points of the side of the head, but I don't know how to express different ratios using these extremities.



Calculating Average Ratios Of Human Faces From Images Of Differing Lengths To The Camera
Was way overthinking this, by dividing the two extreme points to get a factor and then dividing each ratio by this factor I can get ratios proportional to the head size.


