Endoscope apparatus

An endoscope apparatus comprising:

• a light source unit comprising:
• a first light source configured to emit first narrow band light towards an observation object selected based on an absorption spectrum of a first characteristic substance in the observation object, wherein the first characteristic substance is hemoglobin;
• and
• a second light source configured to emit second narrow band light towards the observation object selected based on an absorption spectrum of a second characteristic substance in the observation object, wherein the second characteristic substance is an externally derived substance that is dispersed, administered or applied to the observation object;
• an image sensor;
• and
• a processor comprising hardware, wherein the processor is configured to:
• receive selection of a two-substance observation mode for observation of both the first characteristic substance and the second characteristic substance;
• in response to receiving selection of the two-substance observation mode, control the first light source to emit the first narrow band light and the second light source to emit the second narrow band light towards the observation object;
• control the image sensor to separately acquire a first image of the observation object illuminated by the first narrow band light and to acquire a second image of the observation object illuminated by the second narrow band light;
• extract a characteristic substance region related to the first characteristic substance in the first image as a first characteristic substance region;
• extract a characteristic substance region related to the second characteristic substance in the second image as a second characteristic substance region;
• extract an overlapping region of the first characteristic substance region and the second characteristic substance region, as a characteristic substance overlapping region;
• and
• control a display to display a display image of the observation object acquired by the image sensor having a visibility of the characteristic substance overlapping region enhanced in the display image.