How to check the accuracy of multivariate regression?

Question

Python

Good day, there is a task to localize a face in the image
There is a model ending with a Dense (4) layer, that is, two coordinates, two values ​​​​for x, two for y
The model is compiled with the rmsprop optimizer, mse is used for the loss function
The data is a photograph and two coordinates
It seems to me that you need to check the accuracy through mae, is that right?
If yes, how to apply it to the list of 4 values ​​output by the model?

Answer 1

At a minimum, you need to calculate IoU - both in terms of loss function and in evaluating the result.