The present invention relates to an electronic endoscope system for acquiring information on a blood vessel from an image acquired by an electronic endoscope and producing an image from the acquired information.
In recent years, a number of diagnoses and treatments using electronic endoscopes have been made in the field of medicine. A typical electronic endoscope is equipped with an elongated insertion section that is inserted into a subject's body cavity. The insertion section has therein incorporated an imager such as a CCD at the tip thereof. The electronic endoscope is connected to a light source device, which emits light from the tip of the insertion section to illuminate the inside of a body cavity. With the inside of the body cavity illuminated by light, the subject tissue inside the body cavity is imaged by an imager provided at the tip of the insertion section. Images acquired by imaging undergoes various kinds of processing by a processor connected to the electronic endoscope before being displayed by a monitor. Thus, the electronic endoscope permits real-time observation of images showing the inside of the subject's body cavity and thus enables sure diagnoses.
The light source device uses a white light source such as a xenon lamp capable of emitting white broadband light whose wavelength ranges from a blue region to a red region. Use of white broadband light to illuminate the inside of a body cavity permits observing the whole subject tissue from the acquired images thereof.
However, although images acquired by broadband light illumination permit generally observing the whole subject tissue, there are cases where such images fail to enable clear observation of subject tissues such as micro-blood vessels, deep-layer blood vessels, pit patterns, and uneven surface profiles formed of recesses and bumps.
As is known, such subject tissues may be made clearly observable when illuminated by narrowband light having a wavelength limited to a specific range. As is also known, image data obtained by illumination with narrowband light yields various kinds of information on a subject tissue such as oxygen saturation level in a blood vessel.
For example, JP 2660009 B comprises filters each exclusively corresponding to their respective wavelength ranges for a color image (normal image), an oxygen saturation level image, and a blood vessel distribution image produced using ICG fluorescence, respectively, permitting selective display of such images and, hence, comparison between, for example, a special image containing blood information and a normal visible-wavelength image.