Patent ID: 8668639

Claim:
An image obtainment apparatus comprising: an illumination light illuminating unit that illuminates a region to be observed with illumination light output from a light source; an image obtainment unit that obtains an image of the region to be observed by imaging, by an imaging device, light output from the region to be observed by illumination with the illumination light; a light amount control unit that controls the light amount of the illumination light output from the light source; and an electronic shutter speed control unit that controls the electronic shutter speed of the imaging device, wherein the electronic shutter speed control unit controls the electronic shutter speed at a first constant speed, and the light amount control unit controls the light amount of the illumination light output from the light source based on the light amount of the illumination light with which the region to be observed has been illuminated, when the light amount of the illumination light with which the region to be observed has been illuminated is less than or equal to a first threshold value, and wherein the electronic shutter speed control unit controls the electronic shutter speed at a speed based on the light amount of the illumination light with which the region to be observed has been illuminated, and the light amount control unit controls the light amount of the illumination light output from the light source at a predetermined constant light amount, when the light amount of the illumination light with which the region to be observed has been illuminated is greater than the first threshold value and less than or equal to a second threshold value that is larger than the first threshold value, and wherein the electronic shutter speed control unit controls the electronic shutter speed at a second constant speed that is higher than the first constant speed, and the light amount control unit controls the light amount of the illumination light output from the light source based on the light amount of the illumination light with which the region to be observed has been illuminated, when the light amount of the illumination light with which the region to be observed has been illuminated is greater than the second threshold value.