Image data processing device and image data processing method

An image data processing device for processing image data obtained by imaging light of a subject, which has been spectrally separated into a plurality of wavelengths through a band-pass filter, with an image sensor, the image data processing device comprising:

• a processor,
• wherein the processor is configured to:
• acquire as first image data, which is image data obtained by imaging light of the subject under an imaging condition in which a specific environment in which influence of disturbance light is suppressed;
• calculate a feature amount in a transmission wavelength range of the band-pass filter on the basis of the first image data;
• and
• calculate information of spectral characteristics of the subject on the basis of the feature amount.