Surgery – Endoscope – Having imaging and illumination means
Reexamination Certificate
2001-10-03
2003-12-16
Roane, Aaron (Department: 3739)
Surgery
Endoscope
Having imaging and illumination means
C600S178000
Reexamination Certificate
active
06663561
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a video endoscope system that enables an object to be observed through autofluorescence caused from a living body.
2. Description of the Related Art
Video endoscope system for obtaining a color image of an object under examination, for example a coelomic wall of the living body and the like, are known and being utilized. RGB frame sequential system is also known as method for obtaining a color image of an object under examination. The RGB frame sequential system is adapted to obtain a color video signal by synthetically combining monochromatic video signals obtained separately while the object under examination is being irradiated with blue, green and red light, respectively.
Besides, video endoscope systems enable a living body to be observed through fluorescence (i.e., autofluorescence) generated from the living body when the living body is irradiated with excitation light. The autofluorescence generated from diseased tissue is weaker than the autofluorescence generated from healthy tissue. Therefore, an operator can explore the object under examination through the autofluorescence generated from the object and recognize an area where the autofluorescence is weak as a diseased area.
Recently, video endoscope systems that are adopted with the RGB frame sequential system and incorporated with the functional feature of fluorescence observation have been proposed. Such a video endoscope system can display both an ordinary moving color image of an object under examination and a moving fluorescent image of the object based on the autofluorescence generated from the object. Therefore, the operator using the video endoscope system can selectively acquire either the ordinary moving color image of the object or the moving fluorescent image of the object based on the autofluorescence generated from of the object. Such a video endoscope system has a light source unit for emitting light with which the object is irradiated, and a CCD for picking up an image of the object that is illuminated with the light. When the video endoscope system is operating in the ordinary observation mode, the light source unit emits blue, green and red light sequentially and repeatedly. When, on the other hand, the video endoscope apparatus is operating in the fluorescence observation mode, the light source unit emits excitation light and white light alternately and repeatedly.
FIG. 19
is a timing chart for illumination of light emitted from the light source unit and processes of image acquirement by the CCD. Firstly, the operation of the video endoscope system in the ordinary observation mode will be described by referring to FIG.
19
A and FIG.
19
B.
FIG. 19A
shows the operation of the CCD in the ordinary observation mode and
FIG. 19B
shows the periods in which illumination light emitted from the light source unit is irradiated in the ordinary observation mode. A “B irradiation” period during which blue light is emitted from the light source unit corresponds to a “B accumulation” period for the CCD, which means that an electric charge corresponding to the image of the object formed from blue light is accumulated in each pixel of the CCD when the object under examination is irradiated with blue light. The electric charge accumulated in the “B accumulation” period is output as B video signal in a “B transfer” period that comes immediately after the “B accumulation” period. The “G accumulation” period that comes immediately after the “B transfer” period corresponds to a “G irradiation” period during which green light is emitted from the light source unit, which means that an electric charge corresponding to the image of the object formed from green light is accumulated in each pixel of the CCD during the “G accumulation” period. The electric charge accumulated in the “G accumulated period is output as G video signal in a “G transfer” period that comes immediately after the “G accumulation” period. The “R accumulation” period that comes immediately after the “G transfer” period corresponds to an “R irradiation” period during which red light is emitted from the light source unit, which means that an electric charge corresponding to the image of the object formed from red light is accumulated in each pixel of the CCD during the “R accumulation” period. The electric charge accumulated in the “R accumulation” period is output as R video signal in an “R transfer” period that comes immediately after the “R accumulation” period. Then, a color video signal representing a color image of the object under examination is synthesized from the B video signal, the G video signal and the R video signal output sequentially from the CCD.
Next, the operation of the video endoscope system in the fluorescence observation mode will be described with reference to FIG.
19
C and FIG.
19
D.
FIG. 19C
shows the operation of the CCD in the fluorescence observation mode and
FIG. 19D
shows the periods in which illumination light emitted from the light source unit is irradiated in the fluorescence observation mode. The object under examination generates autofluorescence as it is irradiated with excitation light (ultra violet light). Then, the CCD picks up the image formed from the autofluorescence generated from the object. Thus, a “UV irradiation” period during which the excitation light (ultra violet light) is emitted from the light source unit corresponds to an “F accumulation” period for the CCD, which means that an electric charge corresponding to the image of the object formed from the autofluorescence generated from the object is accumulated in each pixel of the CCD when the object under examination is irradiated with the excitation light. The electric charge accumulated in the “F accumulation” period is output as F video signal in an “F transfer” period that comes immediately after the “F accumulation” period. A “W irradiation” period during which white light is emitted from the light source unit corresponds to a “W accumulation” period of the CCD, which means that an electric charge corresponding to the image of the object formed from the white light is accumulated in each pixel of the CCD when the object under examination is irradiated with the white light. The electric charge accumulated in the “W accumulation” period is output as W video signal in a “W transfer” period that comes immediately after the “W accumulation” period. A video signal as to the object to be used for diagnosis is synthesized from the F video signal and the W video signal output from the CCD. More specifically, the video signal of the object, to be used for diagnosis is obtained by subtracting the F video signal from the W video signal.
In the above described video endoscope system, the “W irradiation” period is as long as the “UV irradiation” period, as shown in FIG.
19
D. Therefore, the “W accumulation” period is as long as the “F accumulation” period, as shown in FIG.
19
C. Now, the autofluorescence generated from the object is very weak. Therefore, when obtaining a video signal to be used for diagnosis is generated from a W video signal and an F video signal, the F video signal needs to be greatly amplified. However, as the amplification factor is increased, the S/N ratio of the F video signal falls and the video signal to be used for diagnosis which is ultimately obtained may contain a high level of noise.
SUMMARY OF THE INVENTION
In view of the above identified circumstances, it is therefore the object of the present invention to provide a video endoscope system which is adapted to obtain an image to be used for diagnosis, without lowering the S/N ratio.
In the first aspect of the present invention, the above object is achieved by a video endoscope system which has an illuminating optical system for illuminating an object under examination, and a light source unit which emits visible light and excitation light for exciting a living tissue of the object to cause fluorescence. The light source unit alternately transmits the visible light and the excitation light t
Enomoto Takayuki
Ozawa Ryo
Sugimoto Hideo
Greenblum & Bernstein P.L.C.
Pentax Corporation
Roane Aaron
LandOfFree
Video endoscope system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Video endoscope system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Video endoscope system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3134745