Apparatus and method for determining a condition of a solid object, vehicle, mobile device and method for training a machine-learning model

An apparatus for determining a condition of a solid object, the apparatus comprising:

• interface circuitry configured to receive image data representing a sequence of images, wherein each image of the sequence comprises a plurality of pixels representing a spatial distribution of intensities of reflected light being reflected from a surface of the solid object, and wherein each image of the sequence represents the intensities for a different light polarization;
• and
• processing circuitry configured to:
• determine, for at least part of the pixel positions in the images of the sequence, a respective Mueller matrix based on the intensities given in the images of the sequence;
• decompose the respective Mueller matrix to determine one or more optical property of the surface for the respective pixel position;
• and
• determine information on the condition of the solid object based on the one or more optical property of the surface for the respective pixel position.