A device measures a spectral distribution with respect to each of a plurality of color charts, sets default values to band specification data, and computes a camera output signal based on spectral sensitivity of the multiband camera and spectral feature of light from each of the plurality of charts. The device computes a candidate value of a spectral estimation parameter from the measured spectral distribution of each color chart and the computed camera output signal. The device successively varies the band specification data from the default values to make an evaluation function approach a target value, determines a spectral estimation parameter corresponding to the band specification data when the evaluation function reaches the target value. The evaluation function is defined to correlate the measured spectral distribution of each color chart to a spectral estimation value computed from the candidate value of the spectral estimation parameter and the camera output signal.