A method for estimating one or more of the following quantities from an electromechanical machine and/or component, the method comprising the creation of a photorealistic numerical model of the electromechanical machine or parts of it, a measurements step for combining outputs of physical sensors of which at least one is an imaging device for visualizing the external surface of the physical electromechanical machine in at least one 2-dimensional image, an estimation step combining the photorealistic numerical model and measurement step to provide an estimate of desired electromechanical quantities, wherein the estimation step is based at least on the usage of a similarity metric between the (at least one) two dimensional image of the electromechanical machine or parts of it and the images generated by the photorealistic numerical model.