JP2771844B2 - Endoscope image observation device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscopic image observation device for observing fluorescence of a fluorescent agent injected into a test site.

[Prior art] In recent years, by inserting an elongated insertion portion into a body cavity,
2. Description of the Related Art Endoscopes capable of observing organs in a body cavity and the like and performing various treatments using a treatment tool inserted into a treatment tool channel as necessary are widely used.

Also, various electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging unit have been proposed.

By the way, as an apparatus for inspecting the state of internal organs and the like of a human body, for example, as shown in JP-A-63-122421,
2. Description of the Related Art There has been known an endoscope apparatus which administers a fluorescent agent to a test site such as an internal organ, irradiates the fluorescent agent with excitation light, and observes a fluorescent image by fluorescence emitted from the fluorescent agent.

[Problems to be Solved by the Invention] Here, fluorescent agents such as fluorescein and adreamycin generally have an absorption band on the short wavelength side and a band emitting fluorescence on the long wavelength side. In addition, an endoscope image generally has a strong red color. Therefore, when observing the fluorescence simultaneously with the normal observation, even if the test site of the endoscope emits fluorescence, the fluorescence is on the super-wavelength side, that is, close to red, so it is buried in the endoscope image, Fluorescence could not be clearly recognized.

In order to solve this, it is conceivable to emphasize the wavelength region of the fluorescence. However, as described above, since the fluorescence is close to red, it is difficult to make a relative difference from the original red of the test site in the endoscope image, and a sufficient enhancement effect cannot be obtained.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an endoscopic image observation device capable of observing fluorescence more clearly.

[Means for Solving the Problems] An endoscopic image observation apparatus according to the present invention is characterized in that a fluorescent agent that absorbs light in a first wavelength band and emits fluorescence in a second wavelength band, which is injected into a test site, is used. An apparatus for observing fluorescence, comprising: an irradiation unit configured to sequentially irradiate a plurality of irradiation lights having different wavelength bands including light in a band near the first wavelength band to the test site; Imaging means for receiving light from the test site irradiated with irradiation light by means, processing means for converting a signal from the imaging means to a video signal, and processing the video signal in the first wavelength band. Means for expanding the difference in video signal level between a nearby band and a wavelength band different from this band is provided.

[Action] In the present invention, the first means that the fluorescent agent absorbs by the irradiation means.
A plurality of irradiation lights having different wavelength bands, including light in a band in the vicinity of the wavelength band, are sequentially radiated to the test site. When the fluorescent agent injected into the test site is irradiated with light in a band near the first wavelength band, the fluorescent agent emits fluorescence. The light including the fluorescence from the test site is received by the imaging unit, and the signal from the imaging unit is converted into a video signal by the processing unit. For this video signal, the difference in video signal level between a band near the first wavelength band and a wavelength band different from this band is enlarged.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 9 relate to an embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of the endoscope apparatus, FIG. 2 is an explanatory view showing a band limiting filter unit, FIG. 3 is a functional block diagram of an arithmetic processing unit, and FIG. 4 shows the entire endoscope apparatus. FIG. 5 is a characteristic diagram showing a transmission wavelength region of each filter of the rotary filter. FIG. 6 is a characteristic diagram showing a transmission wavelength region of one filter of the band-limiting filter unit.
The figure is a characteristic diagram showing the absorption and fluorescence characteristics of fluorescein.
FIG. 8 is a two-dimensional histogram of GB of the endoscope image before the enhancement processing, and FIG. 9 is a two-dimensional histogram of GB of the endoscope image after the enhancement processing.

The endoscope apparatus according to the present embodiment includes an electronic endoscope 1 as shown in FIG. The electronic endoscope 1 has a slender, for example, flexible insertion section 2, and a large-diameter operation section 3 is connected to the rear end of the insertion section 2. A flexible cable 4 extends laterally from a rear end of the operation unit 3, and a connector 5 is provided at a distal end of the cable 4. The electronic endoscope 1 is connected via the connector 5 to a video processor 6 having a light source device and a signal processing circuit built therein. Further, a monitor 7 is connected to the video processor 6.

On the distal end side of the insertion portion 2, a rigid distal end portion 9 and a bending portion 10 which can be bent rearward adjacent to the distal end portion 9 are sequentially provided. By rotating a bending operation knob 11 provided on the operation section 3, the bending section 10 is rotated.
Can be bent in the horizontal direction or the vertical direction. The operation section 3 is provided with an insertion port 12 communicating with a treatment instrument channel provided in the insertion section 2.

As shown in FIG. 1, a light guide 14 for transmitting illumination light is inserted into the insertion section 2 of the electronic endoscope 1. The distal end surface of the light guide 14 is arranged at the distal end 9 of the insertion section 2 so that illumination light can be emitted from the distal end 9. The light guide 14 has an incident end inserted into the universal cord 4 and connected to the connector 5. Further, an objective lens system 15 is provided at the distal end portion 9, and a solid-state imaging device 16 is provided at an image forming position of the objective lens system 15. This solid-state imaging device 16
Has sensitivity in a wide wavelength range from the ultraviolet region to the infrared region including the visible region. Signal lines 26 and 27 are connected to the solid-state imaging device 16. These signal lines 26 and 27 are inserted into the insertion section 2 and the universal cord 4 and connected to the connector 5.

On the other hand, the video processor 6 is provided with a lamp 21 that emits light in a wide band from ultraviolet light to infrared light. As the lamp 21, a general xenon lamp, a strobe lamp, or the like can be used. The xenon lamp and the strobe lamp emit a large amount of ultraviolet light and infrared light as well as visible light. This lamp 21 is connected to a power supply 22
Is supplied with power. A rotary filter 50 driven by a motor 23 is provided in front of the lamp 21. In the rotary filter 50, filters for transmitting light in the respective red (R), green (G), and blue (B) wavelength regions for normal observation are arranged along the circumferential direction. FIG. 5 shows the transmission characteristics of each filter of the rotary filter 50.

The rotation of the motor 23 is controlled by a motor driver 25 to be driven.

A wavelength limiting filter unit 51 is provided on the illumination light path between the rotary filter 50 and the light guide 14 entrance end. As shown in FIG. 2, the wavelength limiting filter unit 51 includes, as shown in FIG. 6, a filter 51a that transmits only the visible light region, and a filter 51a that transmits all the light emitted by the lamp 21 or an observation and fluorescent agent. Filter (or holes may be used) that cuts the area not required for the excitation of
51b. This wavelength limiting filter unit 51
Is rotated by a motor 52 whose rotation is controlled by a filter switching device 55. The filter switching device 55 is controlled by a control signal from the switching circuit 43. Then, by selecting the observation wavelength by the switching circuit 43, a filter corresponding to the observation wavelength selected by the switching circuit 43 among the filters 51a and 51b of the wavelength limiting filter unit 51 is provided on the illumination optical path. The motor 52 is rotated so as to be mounted, and the position of the wavelength limiting filter unit 51 is changed.

The light that has passed through the rotary filter 50 and has been separated in time series into light in the R, G, and B wavelength regions is further transmitted through a selected filter of the wavelength limiting filter unit 51, and the light guide This light guide is incident on 14 entrance ends.
The light is guided to the distal end portion 9 through 14 and emitted from the distal end portion 9 to illuminate the observation site.

The return light from the observation site due to the illumination light is imaged on the solid-state imaging device 16 by the objective lens system 15, and is photoelectrically converted. This solid-state imaging device 16 includes:
A drive pulse from a driver circuit 31 in the video processor 6 is applied via the signal line 126, and reading and transfer are performed by the drive pulse. The video signal read from the solid-state imaging device 16 is input to a preamplifier 32 provided in the video processor 6 or the electronic endoscope 1 via the signal line 27. The video signal amplified by the preamplifier 32 is input to a process circuit 33, subjected to signal processing such as γ correction and white balance, and converted into a digital signal by an A / D converter. The digital video signal is supplied by a select circuit 35 to three memories (1) 36a, memories (2) 36b, and memories (3) corresponding to, for example, each color of red (R), green (G), and blue (B). 36c is selectively stored. The memory (1) 36a, the memory (2) 36b, and the memory (3) 36c
Are simultaneously read out, converted to analog signals by a D / A converter 37, output as R, G, B color signals, input to an encoder 38, and output from the encoder 38 as an NTSC composite signal. It has become.

Then, the R, G, B color signals or the NTSC composite signals are input to a color monitor 7, and the color monitor 7 displays the observation region in color.

In the video processor 6, a timing generator 42 for generating the timing of the entire system is provided, and the timing generator 42 synchronizes the circuits such as the motor driver 25, the driver circuit 31, and the select circuit 35. ing.

In this embodiment, the signal is output from the D / A converter 37.
The R, G, and B color signals are captured and stored in the moving image file 101. This moving image file 101 may capture all moving images, or may capture images at predetermined intervals. The image stored in the moving image file 101 is input to and stored in the image data file 103 via the input / output interface 102.
The image data file 103 picks up the image of the moving image file 101 at an interval of about one second, digitizes the image, and stores the digitized image. The R, G, B data from the image data file 103 is input to an arithmetic processing unit (CPU) 104, where a predetermined enhancement process is performed,
The data is input to the monitor 106 via the input / output interface 105. Then, the endoscope image after the enhancement processing is displayed on the monitor 106.

The arithmetic processing unit 104 has a functional configuration as shown in FIG.

That is, the input G and B signals are input to the noise elimination filters 112 and 113, respectively, to perform noise elimination. The noise elimination filters 112 and 113 are configured by, for example, median filters, and perform noise elimination and halation elimination. The noise removal filters 112 and 113
Are input to the inverse γ correction units 114 and 115, respectively. The inverse γ correction means 114 and 115 receive an input of 2. for setting the density gradation to γ = 1, for example.
It is designed to be squared. Outputs of the inverse γ correction units 114 and 115 are input to an enhancement processing unit 116. This emphasis processing means 116 Is performed. In addition, (1)
In the formula, c is a multiplier for changing the degree of emphasis, and can be arbitrarily adjusted. For example, c = 5.

Output signals G 'and B' of the emphasis processing means 116 are input to γ correction means 117 and 118, respectively. The γ correction means 117 and 118 provide a γ
= 0.45.

The input R signal is input to the delay unit 111, and is delayed by the time required for the above-described processing on the G and B signals.
The signal is output as an R 'signal.

The R ′ signal and the G ′ signal from the γ correction means 117 and 118,
The B ′ signal is the output of the processing unit 104.

 Next, the operation of the present embodiment will be described.

When the wavelength is limited by the filter 51a of the wavelength limiting filter unit 51 as shown in FIG. 6, the emission wavelength of the illumination lamp 21 is sequentially limited by the rotating filter 50, and as shown in FIG. The light is color-separated into light of each wavelength of R, G, and B, and this light is radiated on a mucous membrane of a living body or the like in time series. Then, with this light, a color image in a normal visible light range is obtained.

By the way, when a fluorescent substance called fluorescein having absorption and fluorescence characteristics as shown in FIG. 7 is injected intravenously while observing the living mucous membrane with a normal color image, the fluorescein in the blood changes with time. In concentration changes. This change depends on changes in blood flow and blood volume.

Here, as shown in FIG. 7, the fluorescein has an absorption characteristic substantially coincident with the wavelength region of B, and absorbs this light to emit fluorescence in the wavelength region of G. Therefore, when the light of each wavelength region of R, G, and B is illuminated in time series by the rotation filter 50, the fluorescence becomes weaker at the time of R and G illumination than at the time of illumination by B. That is, if the concentration of fluorescein in the mucous membrane is high during B illumination, this mucosa emits fluorescence, but during signal processing, it emits fluorescence at the timing of B, so that the B image changes regardless of the wavelength of the fluorescence. Processing is performed. That is, the B component in the color image increases due to the fluorescence. Therefore, the concentration distribution of fluorescein and its chronological change can be observed by changing the color tone.

In the present embodiment, when observing the fluorescence,
It is not necessary to switch the wavelength limiting filter unit 51 to the filter 51b. Further, the wavelength limiting filter unit 51 is not always necessary.

In this embodiment, the RGB image is input to the arithmetic processing device 104 via the moving image file 101, the input / output interface 102, and the image data file 103. In the arithmetic processing device 104, G, B
Is processed so as to enlarge the difference between the video signal levels. That is, the data distribution in the GB plane is stretched with the direction in which G and B have a negative correlation as the axis of extension. The G 'and B' signals after such processing and the R 'signal delayed without performing the processing are input to the monitor 106, and the monitor 106 displays the endoscope image after the enhancement processing.

Here, as an example, a change over time in fluorescence of a test site such as the large intestine after intravenous injection of fluorescein will be described.

As described above, in the present embodiment, the generation of the fluorescence is observed as an increase in the density value of the B image. FIGS. 8 (a) to 8 (d) show GBs of endoscope images before fluorescein intravenous injection, 36 seconds, 41 seconds and 46 seconds after intravenous fluorescein injection, respectively.
Is a two-dimensional histogram. In this figure, the horizontal axis is G
The vertical axis indicates the density value of B. As shown in FIG. 8 (a), the histogram before intravenous injection of fluorescein
This shows that GB has a very strong positive correlation, which is consistent with the histogram of GB in general endoscopic images.
However, as shown in FIGS. 8 (c) and (d), in the histograms at 41 seconds and 46 seconds after the appearance of the fluorescence, a branch is found in the data distribution, which branches upward from the main distribution. . This branch indicates the existence of a portion where the value of the B concentration value is relatively larger than the G concentration value, and it is estimated that the data of the portion where strong fluorescence is generated are plotted upward.

FIGS. 9 (a) to 9 (d) show the enhancement processing by the formula (1) on the endoscopic images before fluorescein intravenous injection and 36 seconds, 41 seconds and 46 seconds after intravenous fluorescein injection, respectively. Is a two-dimensional histogram of GB of the image subjected to the above.

In the image before the generation of the fluorescent light, the G density value is slightly higher than the B density value almost uniformly in the entire image, so that the image as a result of the emphasis processing has a yellowish color as a whole, and FIG. As shown in the figure, B decreases and G increases. When fluorescence is generated, the G density value increases, and as a result of the enhancement process, the fluorescence generation site rapidly changes to magenta. That is, G decreases and B increases. This is shown in FIG. 9 (c),
As shown in (d), it can be seen from the fact that the data distribution is expanded in the direction where G and B have a negative correlation.

As described above, according to the present embodiment, the portion to be inspected is irradiated with the R, G, and B plane-sequential illumination light including the band B in the vicinity of the absorption wavelength band of fluorescein, and the absorption wavelength band of fluorescein is absorbed. Since the enhancement processing is performed so as to enlarge the difference in the video signal level between the nearby band B and the wavelength band G different from the band B, the fluorescence can be more clearly observed. On the other hand, in the endoscope image obtained by the simultaneous endoscope, if the wavelength range of the fluorescence of fluorescein is emphasized, the fluorescence is close to red, so It is difficult to make a difference relative to the original red color of the inspection site, and a sufficient emphasis effect cannot be obtained.

Therefore, according to the present embodiment, it is possible to more clearly observe and measure time-series changes in information due to fluorescence, for example, temporal changes in the distribution state of the fluorescent agent on the mucosal surface after intravenous injection of the fluorescent agent. It becomes possible.

In addition, in this way, by observing or measuring the time-series change of the mucous membrane after intravenous injection of the fluorescent agent, in particular, in the case of fluorescein, the time-series change between the B image and the other G, R images, By grasping the hemodynamics of the mucosal surface of a living body, the ability to observe a lesion is improved and the ability to diagnose is improved.

Further, according to this embodiment, even if the emission of the fluorescent agent is not in the visible light range, the information based on the fluorescence can be observed as a change in the color tone of the image.

The present invention is not limited to the above embodiments. For example, the fluorescent agent may be adreamycin, hematoporpherin, pheophorbide a, or the like, and the surface sequential light containing the light in the absorption wavelength band of the fluorescent agent used. By irradiating the test site with light, the fluorescence can be observed as a change in color tone.

Further, the emphasis method is not limited to the matrix operation, and the data distribution in the color space or the chromaticity diagram may be enlarged. The emphasizing process may be performed by hardware.

In addition, the present invention is not limited to an electronic endoscope having a solid-state imaging device at the distal end of the insertion portion, and may be replaced with an eyepiece of an endoscope such as a fiberscope capable of observing the naked eye or with the eyepiece. Thus, the present invention can also be applied to an endoscope apparatus used by connecting a television camera.

[Effects of the Invention] As described above, according to the present invention, a plurality of fluorescent materials having different wavelength bands from each other including light in a band near the first wavelength band in which a fluorescent agent injected into a test site absorbs light. Irradiation light,
Irradiation is sequentially performed on the test site, and an enhancement process is performed so as to enlarge the difference in video signal level between a band near the first wavelength band and a wavelength band different from this band. This has the effect of allowing clear observation.

[Brief description of the drawings]

1 to 9 relate to an embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of an endoscope apparatus, FIG. 2 is an explanatory diagram showing a band limiting filter unit, and FIG. FIG. 4 is a side view showing the entire endoscope device, FIG. 5 is a characteristic diagram showing a transmission wavelength region of each filter of the rotary filter, and FIG. 6 is one of band-limiting filter units. FIG. 7 is a characteristic diagram showing the absorption and fluorescence characteristics of fluorescein, FIG. 8 is a two-dimensional histogram of GB of an endoscope image before enhancement processing, and FIG. Is a GB two-dimensional histogram of the endoscope image after the enhancement processing. DESCRIPTION OF SYMBOLS 1 ... Electronic endoscope, 16 ... Solid-state image sensor 21 ... Lamp, 50 ... Rotating filter 51 ... Wavelength limiting filter unit 104 ... Arithmetic processing unit 116 ... Emphasis processing means

Continuation of the front page (72) Inventor Keiichi Hiyama 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (56) References JP-A-63-122421 (JP, A) JP-A-1- 223930 (JP, A) JP-A-2-200237 (JP, A) JP-A-1-113018 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) A61B 1/00

Claims (1)

(57) [Claims] 1. An endoscope image observation device for observing the fluorescence of a fluorescent agent that absorbs light in a first wavelength band and emits fluorescence in a second wavelength band, which is injected into a test site, Irradiating means for sequentially irradiating the test site with a plurality of irradiation lights having different wavelength bands including light in a band near the first wavelength band; and the test site irradiated with the irradiation light by the irradiation means. An imaging unit that receives light from the imaging unit; a processing unit that uses a signal from the imaging unit as a video signal; a band near the first wavelength band; and a wavelength band different from the band for the video signal. Means for enlarging the difference in video signal level between the endoscope image observation device and the endoscope image observation device.