Abstract: A method of determining a material property of an object. The method comprises: obtaining a real light intensity value for each of a first number of light source positions and each of a second number of light sensor positions, the real light intensity value indicating an intensity of light from the light source position that is reflected or diffused by an object to the light sensor position; determining a three-dimensional surface of the object; and for each of a plurality of points on the three-dimensional surface of the object, using a model that has been trained by machine learning, predicting the material property for the object at the point based on the obtained real light intensity values.