Fluorescence observation device, endoscopic system, processor device, and operation method

A fluorescence observation device, comprising:

• an illumination light source that irradiates a subject, at least a part of which is colored with a colorant, with illumination light by which a color due to the colorant can be identified;
• an excitation light source that irradiates the subject with excitation light for emitting fluorescence by exciting a fluorescent material contained in the subject;
• an image sensor that images the subject with the illumination light and outputs a first image signal and that images the subject with the fluorescence and outputs a second image signal;
• and
• a processor unit that
• sets a reference region according to a color due to the colorant,
• sets a region of interest of the subject,
• calculates a normalized fluorescence intensity indicating a normalized emission intensity of the fluorescence by dividing a region-of-interest fluorescence intensity, which is calculated using a pixel value of the region of interest of the subject in the second image signal, by a reference fluorescence intensity calculated using a pixel value of the reference region of the subject in the second image signal, and
• generates a fluorescent image of the region of interest which is pseudo colored based on the normalized fluorescence intensity.

An endoscopic system, comprising:

• a signal light source that irradiates a subject with signal light having a wavelength band where an absorption coefficient changes with an oxygen saturation of blood hemoglobin;
• an excitation light source that irradiates the subject with excitation light for emitting fluorescence by exciting a fluorescent material contained in the subject;
• an image sensor that images the subject with the signal light and outputs a first image signal and that images the subject with the fluorescence and outputs a second image signal;
• and
• processor unit that
• calculates an oxygen saturation of the subject for each pixel based on the first image signal,
• sets a reference region of the subject based on the oxygen saturation,
• sets a region of interest of the subject,
• calculates a normalized fluorescence intensity indicating a normalized emission intensity of the fluorescence by dividing a region-of-interest fluorescence intensity, which is calculated using a pixel value of the region of interest of the subject in the second image signal, by a reference fluorescence intensity calculated using a pixel value of the reference region of the subject in the second image signal, and
• generates a fluorescent image of the region of interest which is pseudo colored based on the normalized fluorescence intensity.

A processor device of an endoscopic system including a signal light source that irradiates a subject with signal light having a wavelength band where an absorption coefficient changes with an oxygen saturation of blood hemoglobin, an excitation light source that irradiates the subject with excitation light for emitting fluorescence by exciting a fluorescent material contained in the subject, and an image sensor that images the subject with the signal light and outputs a first image signal and that images the subject with the fluorescence and outputs a second image signal, the processor device comprising:

• a processor unit that
• calculates an oxygen saturation of the subject for each pixel based on the first image signal,
• sets a reference region of the subject based on the oxygen saturation,
• sets a region of interest of the subject,
• calculates a normalized fluorescence intensity indicating a normalized emission intensity of the fluorescence by dividing a region-of-interest fluorescence intensity, which is calculated using a pixel value of the region of interest of the subject in the second image signal, by a reference fluorescence intensity calculated using a pixel value of the reference region of the subject in the second image signal, and
• generates a fluorescent image of the region of interest which is pseudo colored based on the normalized fluorescence intensity.

An operation method of a device including a signal light source that irradiates a subject with signal light having a wavelength band where an absorption coefficient changes with an oxygen saturation of blood hemoglobin, an excitation light source that irradiates the subject with excitation light for emitting fluorescence by exciting a fluorescent material contained in the subject, and an image sensor that images the subject with the signal light and outputs a first image signal and that images the subject with the fluorescence and outputs a second image signal, the operation method comprising:

• an oxygen saturation calculation step of calculating an oxygen saturation of the subject for each pixel based on the first image signal;
• a reference region setting step of setting a reference region of the subject based on the oxygen saturation;
• a region-of-interest setting step of setting a region of interest of the subject;
• a normalized fluorescence intensity calculation step of calculating a normalized fluorescence intensity indicating a normalized emission intensity of the fluorescence by dividing a region-of-interest fluorescence intensity, which is calculated using a pixel value of the region of interest of the subject in the second image signal, by a reference fluorescence intensity calculated using a pixel value of the reference region of the subject in the second image signal;
• and
• a fluorescent image generation step of generating a fluorescent image of the region of interest which is pseudo colored based on the normalized fluorescence intensity.