A signal processing apparatus configured to separate light from a specified subject into an illumination light component and a pigment component, the illumination light component resulting from a colour of light with which the subject is irradiated and being light reflected from the surface of the subject being imaged, the pigment component resulting from a colour of a pigment of the subject, the signal processing apparatus comprising: a light receiving section configured to capture an image based on light having a first wavelength, an image based on light having a second wavelength, and a subject image, an optical intensity detecting section configured to detect an intensity of the light from the subject at the first wavelength and the second wavelength, the first wavelength being different from the second wavelength; a pigment component identifying section configured to identify the pigment component in the light from the subject, based on (i) a difference between a first absorptance of the subject at the first wavelength and a second absorptance of the subject at the second wavelength and (ii) a difference between the intensity at the first wavelength and the intensity at the second wavelength that are detected by the optical intensity detecting section; an illumination light component identifying section configured to identify the illumination light component in the light from the subject, based on the subject image obtained by image-capturing the subject by the light receiving section, and based on the pigment component identified by the pigment component identifying section; and a subject information storing section configured to store colour information of the subject in association with (i) the difference between the first absorptance and the second absorptance of the subject and (ii) the difference between the detected intensity at the first wavelength and the detected intensity at the second wavelength, wherein the pigment component identifying section is configured to identify the pigment component in the light from the subject, based on the colour information stored in the subject information storing section; characterized in that the apparatus further comprises an illumination light image generating section configured to generated an image of the illumination light component identified by the illumination light component identifying section, by subtracting colour information of the pigment component identified by the pigment component identifying section from colour information of the subject image obtained by image-capturing the subject. a light receiving section configured to capture an image based on light having a first wavelength, an image based on light having a second wavelength, and a subject image, an optical intensity detecting section configured to detect an intensity of the light from the subject at the first wavelength and the second wavelength, the first wavelength being different from the second wavelength; a pigment component identifying section configured to identify the pigment component in the light from the subject, based on (i) a difference between a first absorptance of the subject at the first wavelength and a second absorptance of the subject at the second wavelength and (ii) a difference between the intensity at the first wavelength and the intensity at the second wavelength that are detected by the optical intensity detecting section; an illumination light component identifying section configured to identify the illumination light component in the light from the subject, based on the subject image obtained by image-capturing the subject by the light receiving section, and based on the pigment component identified by the pigment component identifying section; and a subject information storing section configured to store colour information of the subject in association with (i) the difference between the first absorptance and the second absorptance of the subject and (ii) the difference between the detected intensity at the first wavelength and the detected intensity at the second wavelength, wherein the pigment component identifying section is configured to identify the pigment component in the light from the subject, based on the colour information stored in the subject information storing section; characterized in that the apparatus further comprises an illumination light image generating section configured to generated an image of the illumination light component identified by the illumination light component identifying section, by subtracting colour information of the pigment component identified by the pigment component identifying section from colour information of the subject image obtained by image-capturing the subject.