JP4475921B2 - Endoscope system - Google Patents

Description

  The present invention relates to an endoscope system for observing the inside of a body cavity such as the gastrointestinal tract and bronchi.

  As is well known, biological tissue is excited to emit fluorescence when irradiated with light of a specific wavelength. In addition, an abnormal living tissue in which a lesion such as a tumor or cancer has occurred emits weaker fluorescence than a normal living tissue. This reaction phenomenon can also be caused by living tissue below the body cavity wall. In recent years, endoscope systems have been developed that detect abnormalities occurring in a living tissue under a body cavity wall using this reaction phenomenon.

  As one of the endoscope systems, an illumination light for illuminating the inside of a body cavity into which the distal end of the endoscope is inserted and an excitation light for exciting a living tissue under the body cavity wall from one light source. An endoscope system that can supply illumination light and excitation light alternately from the distal end of the endoscope by supplying to the mirror is disclosed in Patent Document 1.

The endoscope system described in Patent Document 1 is a body cavity formed by an image (normal image) in a body cavity formed by illumination light reflected from the surface of a body cavity wall and fluorescence emitted from a living tissue under the body cavity wall. The image (fluorescence image) is alternately acquired through the photographing device, and the special image generated based on the normal image and the fluorescence image is sequentially displayed on the monitor.
JP 2002-336196 A (paragraphs 0068-0071)

  By the way, as is well known, the intensity of fluorescence emitted from a living tissue is very weak compared to the intensity of excitation light irradiated to the living tissue. For this reason, if the intensity of the illumination light and the excitation light are approximately the same, the fluorescence image becomes too dark with respect to the normal image, and a special image with high accuracy cannot be generated. However, as a result of recent technological development, it has become possible to raise the brightness of fluorescent images to the level of normal images. For this reason, recently, there has been a demand for adjusting the brightness of the normal image and the fluorescence image separately to further improve the accuracy of the special image.

  In the case where the illumination light and the excitation light are extracted from one light source as in the endoscope system described in Patent Document 1, the brightness of the normal image and the fluorescence image is separately adjusted as described above. In some cases, it may be considered that the amount of illumination light and excitation light may be adjusted separately using a diaphragm disposed immediately after the light source. However, in such a dimming method that physically cuts the luminous flux by the diaphragm, although the dimming range can be widened, the period of emitting illumination light and excitation light from the distal end of the endoscope is several tens. Since the time is 1 second, there is a problem that the driving of the diaphragm cannot follow the switching timing.

  On the other hand, as a dimming method capable of following the switching timing, Patent Document 1 describes that the output of a light source is electrically adjusted to separately adjust the amounts of illumination light and excitation light. However, according to such electrical output adjustment, since the dimming range is generally narrow, particularly for illumination light that requires a wide dimming range, such electrical output adjustment is performed using the dimming method. There was a problem that could not be adopted as.

  In addition, as a dimming method that can follow the switching timing, a normal image can be obtained by changing the charge accumulation period when the illumination light is emitted (so-called electronic shutter opening period) and the charge accumulation period when the excitation light is emitted. Patent Document 1 describes separately adjusting the brightness balance of a fluorescent image and a fluorescent image. However, when the imaging device captures illumination light reflected with high brightness on the surface of the body cavity wall with the tip of the endoscope approaching the body cavity wall, blooming occurs due to the structure of the imaging device, and a normal image Halation appears inside. As described above, if only the electronic shutter is used to adjust the brightness of the normal image, the image quality of the normal image may not be maintained at a high level. A means of dimming light was necessary.

  The present invention has been made in view of the problems of the prior art as described above, and the problem is that the illumination light and the excitation light extracted alternately from one light source are emitted from the distal end of the endoscope. Thus, when generating a special image based on the normal image and the fluorescent image, it is possible to separately adjust the brightness of the normal image and the fluorescent image while taking physical dimming means for the illumination light. An endoscope system is provided.

  An endoscope system invented to solve the above-described problems is configured as described below.

That is, the endoscope system includes a thin tubular insertion portion for insertion into a body cavity, and an objective optical system that forms an image in the body cavity when the distal end of the insertion portion is inserted into the body cavity. An imaging device that color-shoots an image of a body cavity formed by the objective optical system and outputs image data, and an illumination optical system that guides light from the proximal end to the distal end of the insertion portion and emits the light from the distal end When a white light source for emitting white light toward the illumination optical system, a first excitation Okoshiko transmission filter for extracting the excitation light for exciting the biological tissue from the white light, the first By inserting the second excitation light transmission filter having the same characteristics as the excitation light transmission filter and the first excitation light transmission filter repeatedly into the optical path of the white light at regular intervals, the illumination optical system is The white light and the excitation light An insertion mechanism that repeatedly and alternately introduces, normal image data acquired from the imaging device during a first field period in which white light is introduced into the illumination optical system, and excitation light that is introduced into the illumination optical system. An image processing unit that generates image data for displaying a special image showing a portion that can be estimated as an affected area based on fluorescence image data acquired from the imaging apparatus in a two-field period; and the second excitation light. An aperture mechanism that inserts a transmission filter into the optical path of the white light, and normal image data is acquired from the image processing unit, and the aperture of the normal image based on the acquired normal image data is set to a predetermined level. Fluorescence image data was acquired from the illumination light control unit that controls the amount of insertion of the second excitation light transmission filter into the optical path of the white light by the mechanism, and the image processing unit, and acquired. An excitation light control unit that controls an output amount of the white light from the white light source in the second field period so that the brightness of the fluorescent image based on the light image data becomes a predetermined level. , With features.

  Thus, another optical filter having the same transmission characteristics as the first excitation light transmission filter for extracting the excitation light from the white light source is prepared as the second excitation light transmission filter, and the second excitation light transmission filter is prepared. Can be adjusted in the optical path of white light and the amount of white light as illumination light can be adjusted simply by adjusting the amount of insertion, and as a result, the brightness of a normal image can be adjusted.

  At this time, the second excitation light transmission filter continues to be inserted into the optical path of white light. However, since the amount of excitation light is not affected by the second excitation light transmission filter, the second excitation light transmission filter is consequently obtained. The light transmission filter is used as a physical light control means for the illumination light.

  For the excitation light, the brightness of the fluorescent image is adjusted separately from the brightness of the normal image by adopting a conventional dimming method of controlling the output amount of the white light source during the emission period of the excitation light. be able to.

  If the imaging device of the endoscope system according to the present invention is an image sensor configured to change the charge accumulation period in each pixel in the second field period, the endoscope system includes: A fluorescence control unit that acquires fluorescence image data from the image processing unit and controls an accumulation period in the second field period in the image sensor so that the brightness of the fluorescence image based on the acquired fluorescence image data becomes a predetermined level. Can be further provided.

  As described above, according to the present invention, the special image based on the normal image and the fluorescence image is emitted by emitting the illumination light and the excitation light alternately extracted from one light source from the distal end of the endoscope. In the generation, it is possible to separately adjust the brightness of the normal image and the fluorescent image while taking physical dimming means particularly for the illumination light.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is an external view of an electronic endoscope system according to an embodiment of the present invention. As shown in FIG. 1, the electronic endoscope system includes an electronic endoscope 10, a light source processor device 20, and a monitor 30. FIG. 2 is a configuration diagram schematically showing the inside of the electronic endoscope 10 and the light source processor device 20.

  Although the detailed shape of the electronic endoscope 10 is not shown in FIG. 2, the electronic endoscope 10 has a flexible thin tubular insertion portion 10a for insertion into a body cavity. . A bending portion is incorporated at the distal end of the insertion portion 10a, and an operation portion 10b provided with an angle knob and various switches for operating the bending amount and the bending direction of the bending portion is provided at the base end. It has been.

  At least two through holes are formed in the distal end surface of the insertion portion 10a, and the light distribution lens 11 and the objective lens 12 are fitted in the pair of through holes, respectively.

  Further, the light guide 13 is passed through the insertion portion 10a. The light guide 13 is composed of a large number of flexible optical fibers, and the front end surface thereof faces the light distribution lens 11. The proximal end of the light guide 13 is led through a flexible tube 10c extending from the side surface of the operation unit 10b. It has been fixed.

  Further, an excitation light removal filter 14 is incorporated in the insertion portion 10a. The excitation light removal filter 14 is an optical filter that blocks light in the same wavelength band as the excitation light for exciting the living tissue and transmits light in other wavelength bands. The excitation light removal filter 14 is disposed on the optical axis in a state perpendicular to the optical axis of the objective lens 12.

  Further, an image sensor 15 is incorporated in the insertion portion 10a. The imaging element 15 is a single-plate area image sensor having an imaging surface composed of a large number of pixels arranged two-dimensionally, and a primary color filter is on-chip on the imaging surface. The imaging element 15 is arranged on the side opposite to the side where the objective lens 12 is located with the excitation light removal filter 14 interposed therebetween, and the position of the imaging plane substantially coincides with the position of the image plane of the objective lens 12. ing.

  At least two signal lines 15 a and 15 b are connected to the image sensor 15. One signal line 15a is an electric wire for transmitting a drive signal for the image pickup device 15, and the other signal line 15b is an electric wire for transmitting an image signal output from the image pickup device 15.

  These signal lines 15a and 15b are sequentially passed through the insertion portion 10a and the flexible tube 10c. One signal line 15a is connected to the driver 16 in the connector portion 10d, and the other signal line 15b is , And is fixed to the tip of the connector portion 10d.

  The driver 16 is a circuit for generating a drive signal for the image sensor 15 and outputting it to the image sensor 15. More specifically, the driver 16 supplies the charge in each pixel to the image sensor 15 in one field period starting at one timing indicated by a reference signal output from a timing control unit 21 described later. A signal for instructing to accumulate for a predetermined period and a signal for instructing the image sensor 15 to discharge the accumulated charge of each pixel are output.

  The light source processor device 20 includes a timing control unit 21, a system control unit 22, a light source unit 23, an image processing unit 24, and a light control unit 25.

  Note that a connector receiver into which the connector portion 10d can be fitted is provided on a side surface of the housing of the light source processor device 20. When the connector part 10d is fitted into the connector receptacle, the driver 16 in the connector part 10d is connected to the timing control part 21 and the light control part 25 via a signal line (not shown), and the operation part of the electronic endoscope 10 Various switches provided in 10b are connected to the system control unit 22 via a signal line (not shown), the base end of the light guide 13 enters the light source unit 23, and the signal line 15b is connected to the image processing unit 24. The

  The timing control unit 21 is a controller for generating various reference signals and controlling the output of the signals. Various processes in the light source processor device 20 and the driver 16 in the connector unit 10d proceed according to this reference signal.

  In the light source processor device 20, one cycle (for example, 1/30 second) is defined by a set of two timings indicated by the reference signal, and the second timing from the first timing in the cycle is the second. The period between the timings is defined as a first field period, and the period from the second timing to the first timing in one cycle is defined as a second field period.

  The system control unit 22 is a controller for controlling the entire light source processor device 20. The system control unit 22 is connected to various switches provided on the operation unit 10b of the electronic endoscope 10 and switches on an operation panel (not shown). When an input is received through these switches, the system control unit 22 receives the input. Perform the appropriate process.

  Further, the system control unit 22 switches the observation mode to one of the normal observation mode and the special observation mode in accordance with the switching operation performed on the switch SW on the operation unit 10b of the electronic endoscope 10.

  The light source unit 23 is a unit for emitting light to be introduced into the base end surface of the light guide 13. FIG. 3 is a configuration diagram schematically showing the inside of the light source unit 23. As shown in FIG. 3, the light source unit 23 includes a lamp 231, a rotating plate 232, a first motor 233, a diaphragm plate 234, a second motor 235, a stage mechanism 236, and a third motor 237.

  The lamp 231 is a light source that emits white light having a wavelength component in the entire visible band of about 400 nm to 700 nm toward the base end surface of the light guide 13. The lamp 231 is supplied with power from the power supply circuit 231a.

  The power supply circuit 231a is a circuit for starting or stopping the supply of power to the lamp 231 described above. The power supply circuit 231a is connected to the system control unit 22 via an adder 231c. When a first control value is input from the system control unit 22 to the power supply circuit 231a, power is supplied to the lamp 231. When the input of the first control value is stopped, the supply of power to the lamp 231 is stopped.

  Note that the first control value input from the system control unit 22 to the power supply circuit 231a includes a normal observation mode and a special observation mode. When the first control value indicating the normal observation mode is input from the system control unit 22, the power supply circuit 231a changes the output amount of white light between the first field period and the second field period in the one cycle. The lamp 231 is controlled so that white light is always output at a predetermined output amount without being performed.

  On the other hand, when the first control value indicating the special observation mode is input from the system control unit 22, the power supply circuit 231a determines that the output amount of white light in the first field period is the output amount of white light in the second field period. The lamp 231 is controlled to be increased to a predetermined multiple of.

  Further, the power supply circuit 231a is connected to a dimming unit 25 described later through an adder 231c, and the first control value input from the system control unit 22 to the power supply circuit 231a is adjusted in the special observation mode. A first dimming value (having a positive or negative polarity), which will be described later, output from the light unit 25 is added by the adder 231c (substantially subtracting with a negative polarity).

  When the first control value when the first dimming value is not added is input, the power supply circuit 231a emits white light in the second field period in the special observation mode by a predetermined reference amount. In addition, when electric power is supplied to the lamp 231 and a positive or negative first dimming value is added to the input first control value, the output amount of white light in the second field period in the special observation mode is The amount of power supplied to the lamp 231 during the period is increased or decreased so that the amount is decreased or increased from the predetermined reference amount by an amount corresponding to the absolute value of the first dimming value.

  The rotating plate 232 includes a disc having several through holes and an optical filter fitted in each through hole. FIG. 4 is a front view of the rotating plate 232. The rotating plate 232 has two through holes having the same shape. Each of the through holes is formed in a semicircular arc-shaped band shape, and the center of the semicircular arc coincides with the center of the rotating plate 232. Therefore, on the rotating plate 232, these two through holes are almost ring-shaped as a whole.

  A visible light transmission filter 232a is fitted into one of the two through holes. The visible light transmission filter 232a is an optical filter for transmitting light having a wavelength band of about 400 nm to 700 nm, which is the same as the white light described above.

  The first excitation light transmission filter 232b is fitted into the other through hole. The first excitation light transmission filter 232b is an optical filter for extracting the above-described excitation light from the white light. Specifically, the first excitation light transmission filter 232b transmits only light in the wavelength band of about 400 nm to 450 nm and transmits other light. Shields light in the wavelength band.

  The first motor 233 is an actuator for rotating the rotary plate 232 configured as described above. The rotary plate 232 is coaxial with the drive shaft of the first motor 233 and is near the tip of the drive shaft. It is fixed to. The driving of the first motor 233 is controlled by a synchronization driver 233a. The synchronization driver 233a is a circuit for controlling the driving of the first motor 233 in accordance with the reference signal described above.

  An optical sensor 233b for detecting the rotational phase of the rotary plate 232 is disposed near the center of the rotary plate 232, and the synchronization driver 233a is based on a signal obtained from the optical sensor 233b. The rotational phase of the rotating plate 232 is synchronized with the timing indicated by the reference signal. However, the means for detecting the rotational phase of the rotating plate 232 may be a detector (sensor) assembled to the first motor 233, for example, instead of the optical sensor 233b.

  The diaphragm plate 234 is used to reduce the amount of white light by being inserted into the white light optical path described above. FIG. 5 is a front view of the diaphragm plate 234. The diaphragm plate 234 includes an action part 234a and a shaft part 234b.

  The action part 234a is formed in an oval flat plate shape in which the ratio of the major axis to the minor axis is approximately 2 to 1, and in one of the two regions formed by dividing the minor axis as a boundary line, A through-hole occupying almost the entire area is formed.

  And the 2nd excitation light transmission filter 234c is engage | inserted by this through-hole. The second excitation light transmission filter 234c has the same transmission characteristics as the first excitation light transmission filter 232b fitted in one through hole of the rotating plate 232 described above, and has the same wavelength band as the excitation light. Remove. In addition, the area | region on the opposite side to the side in which this 2nd excitation light transmissive filter 234c exists in this action part 234a is described with the shielding part 234d for convenience.

  On the other hand, the shaft part 234b is formed in a strip-like plate shape, and the tip in the longitudinal direction is fixed to the end of the action part 234a on the side where the second excitation light transmission filter 234c is present. More specifically, the shaft portion 234b is included in the same plane as the action portion 234a in a state where its longitudinal direction is directed to the same direction as the long axis direction of the action portion 234a, so that the action portion 234a is included. Furthermore, in the fixed state, it is coaxial with the action part 234a.

  The second motor 235 is an actuator for rotating the diaphragm plate 234 configured as described above, and its drive shaft is located near the base end of the shaft portion 234b of the diaphragm plate 234 as shown in FIG. It is fixed. The driving of the second motor 235 is controlled by a driving driver 235a.

  The driving driver 235a is a circuit for controlling the driving of the second motor 235. The driving driver 235a is connected to the system control unit 22 via an adder 235c. When a second control value is input from the system control unit 22 to the driving driver 235a, the driving of the second motor 235 is performed. When the second control value input is stopped, the second motor 235 is not driven.

  The drive driver 235a is connected to the dimming unit 25 through the adder 235c, and the second control value input from the system control unit 22 to the drive driver 235a includes the dimming in the special observation mode. The second dimming value (having a positive or negative polarity) output from the unit 25 is added by the adder 235c (substantially subtracting for the negative polarity).

  Then, when the second control value when the second dimming value is not added is input, the driving driver 235a controls the driving of the second motor 235, and a predetermined reference amount is added to the white light optical path. When the diaphragm plate 234 is arranged at the inserted position and the positive or negative second dimming value is added to the input second control value, the driving of the second motor 235 is controlled to The diaphragm plate 234 is disposed at a position where the insertion amount into the optical path is increased or decreased from the predetermined reference amount by an amount corresponding to the absolute value of the second dimming value.

  A position sensor 235b for detecting the amount of rotation of the diaphragm plate 234 is disposed in the vicinity of the base end of the shaft portion 234b of the diaphragm plate 234, and a driving driver 235a is obtained from the position sensor 235b. Based on the signal, the rotation amount of the diaphragm plate 234 is acquired.

  The stage mechanism 236 is a mechanism for translating an object installed on the stage only in a direction orthogonal to the direction in which the white light is emitted from the lamp 231. On the stage, the first motor 233 and the optical sensor are arranged. 233b, a second motor 235, and a position sensor 235b are installed.

  Note that on the stage, the first and second motors 233 and 235 are both oriented in a direction in which the drive axis is orthogonal to the parallel movement direction of the stage. When the stage mechanism 236 is driven in the forward and reverse directions, the rotating plate 232 fixed to the drive shaft of the first motor 233 is inserted / removed perpendicularly to the optical path of white light emitted from the lamp 231.

  The third motor 237 is an actuator for driving the stage mechanism 236. The driving of the third motor 237 is controlled by the movement driver 237a. The movement driver 237 a is a circuit for receiving an instruction from the system control unit 22 and controlling the driving of the third motor 237.

  The stage mechanism 236 is provided with a position sensor 237b for detecting the position of the stage. The system control unit 22 detects the amount of movement of the stage based on a signal obtained from the position sensor 237b. The movement driver 237a is instructed to drive the third motor 237 until the stage reaches a predetermined position.

  More specifically, when the observation mode is switched to the normal observation mode, the system control unit 22 controls the third motor 237 through the moving driver 237a to pull out the rotating plate 232 from the optical path of white light. Until the stage mechanism 236 is driven. FIG. 3 shows the state at this time.

  When the diaphragm plate 234 is rotated forward and backward by the second motor 235 when the stage is at this position, the shielding portion 234d of the diaphragm plate 234 is inserted / removed perpendicularly to the white light optical path. 5 and 6 show the states before and after this insertion / extraction. FIG. 5 shows a state where all of the white light is shielded by the shielding part 234d, and FIG. 6 shows a state where about half of the white light is shielded by the shielding part 234d.

  Further, when the observation mode is switched to the special observation mode, the system control unit 22 controls the third motor 237 through the moving driver 237a until the rotating plate 232 is inserted into the white light optical path. The mechanism 236 is driven. FIG. 7 shows the state at this time.

  When the stage is in this position, the visible light transmission filter 232a is inserted into the white light path in the first field period, and the first excitation light transmission filter 232b is white light in the second field period. Inserted into the optical path. For this reason, white light and excitation light are alternately introduced into the base end face of the light guide 13 in synchronization with the first field period and the second field period.

  If the diaphragm plate 234 is rotated forward and backward by the second motor 235 when the stage is at this position, the second excitation light transmission filter 234c in the diaphragm plate 234 is inserted / removed perpendicularly to the optical path of white light. The 8 and 9 show states before and after this insertion / extraction. FIG. 8 shows a state where all of the white light is incident on the second excitation light transmission filter 234c, and FIG. 9 shows that about one-eighth of the white light is incident on the second excitation light transmission filter 234c. Indicates the state.

  The image processing unit 24 is a unit for performing various types of processing on the image signal sent from the image sensor 15. FIG. 10 is a configuration diagram schematically showing the inside of the image processing unit 24 and the light control unit 25.

  As shown in FIG. 10, the image processing unit 24 includes a first-stage processing circuit 241, a red component memory 242r, a green component memory 242g, a blue component memory 242b, a luminance component generation circuit 243, and a first luminance component memory. 244a, a second luminance component memory 244b, an affected part image data generation circuit 245, a switch circuit 246, an adder 247, and a post-stage processing circuit 248.

  The first stage processing circuit 241 is a circuit for performing predetermined processing on the image signal sent from the image sensor 15. The processing performed on the image signal by the first stage processing circuit 241 includes high-frequency component removal, amplification, blanking, clamping, white balance, gamma correction, analog-digital conversion, and color separation. The first-stage processing circuit 241 generates image data of each color component of red (R), green (G), and blue (B) by performing the above-described processing on the image signal.

  The first stage processing circuit 241 outputs the image data of each color component generated in the first field period to the color component memories 242r, 242g, and 242b, and the image data of each color component generated in the second field period. Are not output to each color component memory 242r, 242g, 242b. Further, the first stage processing circuit 241 outputs the image data of each color component sequentially generated in the first field period and the second field period to the luminance component generation circuit 243.

  The color component memories 242r, 242g, and 242b are memories for temporarily storing RGB color component image data output from the first stage processing circuit 241. Each of these memories 242r, 242g, and 242b outputs each color component image data at a timing according to the reference signal. However, the R component image data is output to the adder 247, but the G component image data and the B component image data are output to the post-processing circuit 248.

  The luminance component generation circuit 243 is a circuit that generates image data of the luminance component (Y component) in the YCrCb color space based on the RGB color component image data output from the first stage processing circuit 241. In other words, the luminance component generation circuit 243 conceptually sets the gradation values (R, G, B) of pixels at the same position in the RGB color component image data to Y = 0.30R + 0.59G + 0.11B. By calculating by substituting into the equation, the luminance value Y of the pixel at that position is calculated.

  The luminance component generation circuit 243 uses the Y component image data based on the color component image data output from the first stage processing circuit 241 after the first field period as Y component normal image data as the first luminance component memory 244a. Y component image data based on each color component image data output from the first stage processing circuit 241 after the second field period is output to the second luminance component memory 244b as Y component fluorescent image data.

  The first luminance component memory 244a is a memory for temporarily storing Y component normal image data, and the second luminance component memory 244b is a memory for temporarily storing Y component fluorescent image data. Each of these memories 244a and 244b outputs both image data to the affected part image data generation circuit 245 at a timing according to the reference signal.

  The affected part image data generation circuit 245 is a circuit that generates affected part image data based on both image data output from the first and second luminance component memories 244a and 244b. More specifically, the affected part image data generation circuit 245 first performs a normalization process for equalizing the gradation widths of both image data, and then calculates the difference between the gradation values of pixels at the same position in both image data. An absolute value is calculated, and image data in which the absolute value of the difference of each pixel is the gradation value of itself is generated as affected part image data.

  The switch circuit 246 is a circuit for opening and closing between the affected part image data generation circuit 245 and the adder 247. The switch circuit 246 is controlled by the system control unit 22 so that the affected part image data is not output to the adder 247 in the normal observation mode, and the affected part image data is output to the adder 247 in the special observation mode. Let

  The adder 247 is a circuit that adds the affected part image data to the R component image data only when the affected part image data is input. That is, the adder 247 passes the R component image data as it is to the post-processing circuit 248 in the normal observation mode, and passes the R component image data obtained by adding the affected part image data to the post-processing circuit 248 in the special observation mode. send.

  The post-stage processing circuit 248 uses the R component image data output from the adder 247 and the G component image data and B component image data output from the G component memory 242g and the B component memory 242b, respectively, for monitor output. It is a circuit for converting into an image signal. Processing performed on each color component image data in the post-stage processing circuit 248 includes digital-analog conversion, encoding, impedance matching, and the like. The post-processing circuit 248 generates a separate video signal and a composite video signal by performing the above-described processing on each color component image data, and outputs it to the monitor 30.

  The monitor 30 is a display device that, when receiving a video signal output from the light source processor device 20, displays a color image based on the video signal.

  The light control unit 25 is a unit for adjusting the brightness of the image based on the image data acquired by the image sensor 15. As shown in FIG. 10, the dimming unit 25 includes a normal image brightness detection circuit 251 and a fluorescent image brightness detection circuit 252.

  The normal image brightness detection circuit 251 determines the image brightness based on the image data acquired by the image sensor 15 in the normal observation mode or the image data acquired by the image sensor 15 in the first field period in the special observation mode. This is a circuit for maintaining a predetermined level. The normal image brightness detection circuit 251 is connected to the luminance component generation circuit 243 and is also connected to an adder 235c incorporated between the system control unit 22 and the driving driver 235a. ing.

  When the luminance component generation circuit 243 outputs the Y component normal image data to the first luminance component memory 244a, the normal image brightness detection circuit 251 acquires the Y component normal image data. When the Y component normal image data is acquired, the normal image brightness detection circuit 251 calculates an average value for one screen of the gradation value of each pixel, and removes a predetermined reference value from the average value. Thereafter, the normal image brightness detection circuit 251 outputs the value obtained by the division to the adder 235c as the second dimming value.

  As described above, the second dimming value is added to the second control value from the system control unit 22 in the adder 235c, and the second control value after the addition is driven from the adder 235c. To the driver 235a. The driving driver 235a decreases or increases the amount of insertion of the diaphragm plate 234 into the optical path of the white light according to the absolute value and polarity of the second dimming value added to the second control value from the predetermined reference amount. The second motor 235 is driven so as to achieve the set amount.

  At this time, if the polarity of the second dimming value is positive (that is, if the brightness of the Y component normal image is brighter than the predetermined reference value), the driving driver 235a moves the aperture plate 234 to the optical path of white light. If the insertion amount is increased from the predetermined reference amount and the polarity of the second dimming value is negative (that is, if the Y component normal image is darker than the predetermined reference value), the diaphragm plate 234 is inserted into the white light optical path. Reduce the amount.

  For this reason, the amount of light introduced into the light guide 13 is reduced when the Y component normal image becomes brighter than the predetermined reference value, and is increased when the Y component normal image becomes darker than the predetermined reference value. As a result, even if the image based on the image data acquired by the image sensor 15 tends to become brighter or darker, the brightness of the image is adjusted so that it always becomes a predetermined level. .

  By the way, in the normal observation mode, as described above, the shielding part 234d of the diaphragm plate 234 is inserted into and removed from the optical path of white light. Since the shielding portion 234d completely shields light, the amount of white light inserted into the light guide 13 is reliably reduced as the amount of insertion of the shielding portion 234d into the optical path increases. As the amount of insertion of the shielding part 234d into the optical path decreases, it is surely increased.

  On the other hand, in the special observation mode, as described above, the second excitation light transmission filter 234c of the diaphragm plate 234 is inserted into and extracted from the optical path of white light. The second excitation light transmission filter 234c allows light in a part of the wavelength band to pass through. However, since the wavelength band is very narrow compared to the wavelength band of white light, the second excitation light transmission filter 234c functions as a shielding plate for white light. Therefore, the amount of white light introduced into the light guide 13 in the first field period is reliably reduced as the amount of the second excitation light transmission filter 234c inserted into the optical path increases, and the optical path As the amount of insertion of the second excitation light transmission filter 234c into is reduced, it is surely increased.

  However, in the second field period in the special observation mode, the light transmitted only through the first excitation light transmission filter 232b of the rotating plate 232 and the second excitation light transmission of the first excitation light transmission filter 232b and the diaphragm plate 234 are transmitted. All the light transmitted through the filter 234c is excitation light having the same wavelength band. That is, even if the second excitation light transmission filter 234c of the diaphragm plate 234 is inserted before and after the rotating plate 232 in the white light optical path, the excitation light is substantially blocked by the second excitation light transmission filter 234c. There is no. Therefore, the amount of excitation light introduced into the light guide 13 in the second field period does not change depending on the amount of the second excitation light transmission filter 234c inserted into the optical path.

  On the other hand, the fluorescence image brightness detection circuit 252 is a circuit for adjusting the brightness of the image based on the image data acquired by the image sensor 15 in the second field period in the special observation mode. The fluorescent image brightness detection circuit 252 is connected to the luminance component generation circuit 243 and also to an adder 231c incorporated between the system control unit 22 and the power supply circuit 231a. Further, it is also connected to the driver 16 in the connector portion 10d of the electronic endoscope 10.

  When the luminance component generation circuit 243 outputs the Y component fluorescent image data to the second luminance component memory 244b, the fluorescent image brightness detection circuit 252 acquires the Y component fluorescent image data. When the Y component fluorescence image data is acquired, the fluorescence image brightness detection circuit 252 calculates an average value for one screen of gradation values of each pixel only in the special observation mode, and determines a predetermined value from the average value. Divide the reference value. Thereafter, the fluorescence image brightness detection circuit 252 outputs the value obtained by the division to the adder 231c and the driver 16 as the first dimming value. However, the first dimming value is output from the fluorescence image brightness detection circuit 252 only in the special observation mode.

  As described above, the first dimming value is added to the first control value from the system control unit 22 in the adder 231c, and the first control value after the addition is supplied from the adder 231c to the power source. Input to the circuit 231a. In the power supply circuit 231a, the output amount of white light in the second field period in the special observation mode decreases from the predetermined reference amount according to the absolute value and polarity of the first dimming value added to the first control value. Alternatively, the supply amount of power to the lamp 231 during the period is increased or decreased so as to increase the amount.

  At this time, if the polarity of the first dimming value is positive (that is, if the brightness of the Y component fluorescent image is brighter than the predetermined reference value), the power supply circuit 231a is white in the second field period in the special observation mode. If the light output amount is decreased from the predetermined reference amount and the polarity of the first dimming value is negative (that is, if the brightness of the Y component fluorescent image is darker than the predetermined reference value), the second light amount in the special observation mode is set. The amount of white light output in the field period is increased from a predetermined reference amount.

  For this reason, the amount of light introduced into the light guide 13 in the second field period in the special observation mode is reduced when the Y component fluorescent image becomes brighter than the predetermined reference value, and the Y component fluorescent image becomes darker than the predetermined reference value. Will be increased. As a result, even if the image based on the image data acquired by the image sensor 15 in the second field period in the special observation mode tends to become brighter or darker, the brightness of the image is always at a predetermined level. To be adjusted.

  When this first dimming value is input to the driver 16, the driver 16 sets the charge accumulation period (so-called electronic shutter opening period) in each pixel of the image sensor 15 during the second field period. It is changed by an amount corresponding to the absolute value of one dimming value.

  At this time, if the polarity of the first dimming value is positive (that is, if the brightness of the Y component fluorescent image is brighter than the predetermined reference value), the driver 16 opens the electronic shutter during the second field period. If the polarity of the first dimming value is negative (that is, if the brightness of the Y component fluorescent image is darker than the predetermined reference value), the electronic shutter during the second field period The opening period of is increased from a predetermined reference period.

  For this reason, even if the image based on the image data acquired by the image sensor 15 in the second field period in the special observation mode tends to become brighter or darker, the brightness of the image is always at a predetermined level. To be adjusted.

  Since the electronic endoscope system of the present embodiment is configured as described above, an operator of this electronic endoscope system can observe the inside of the body cavity by the procedure as described below.

  First, the operator connects the electronic endoscope 10, the light source processor device 20, and the monitor 30, and turns on the light source processor device 20 and the monitor 30. Subsequently, the operator inserts the distal end of the insertion portion 10a of the electronic endoscope 10 into the body cavity and operates the switch SW in the operation portion 10b of the electronic endoscope 10 to switch to the normal observation mode.

  Then, the rotating plate 232 is pulled out from the optical path of the white light emitted from the lamp 231, and the white light is always incident on the base end surface of the light guide 13, and from the distal end of the insertion portion 10 a of the electronic endoscope 10. The white light is continuously emitted to illuminate the body cavity. After the illumination light reflected by the surface of the body cavity wall, the light transmitted through the objective lens 12 is transmitted through the excitation light removal filter 14 to remove the same wavelength component of about 400 nm to 450 nm as the excitation light. , And enters the imaging surface of the image sensor 15. At this time, an image (normal image) in the body cavity is formed on the imaging surface by the objective lens 12.

  The normal image formed on the image pickup surface is picked up by the image pickup device 15 and an image signal is output to the image processing unit 24. In the image processing unit 24, the first-stage processing circuit 241 performs predetermined processing on the image signal to generate image data of each color component of RGB. Each color component image data is output to the post-processing circuit 248 without adding the affected part image data, and is converted into a video signal which is an image signal for monitor output in the post-processing circuit 248. The video signal is output to the monitor 30.

  Therefore, a normal image is displayed on the monitor 30 as a color normal observation image. The operator can observe the state of the body cavity wall while viewing the normal observation image.

  At this time, in the normal image brightness detection circuit 251 of the dimming unit 25, the second dimming value is sequentially generated based on the Y component normal image data acquired from the image processing unit 24, and is sequentially generated. The amount of white light inserted into the optical path of the shielding portion 234d of the diaphragm plate 234 is adjusted according to the amount of change in the light control value. As a result, since the brightness of the normal observation image displayed on the monitor 30 is maintained at a predetermined level, the operator can observe the state of the body cavity wall in detail through the high-quality normal observation image without halation. it can.

  Furthermore, the operator observes the special observation image obtained by using the excitation light for the part selected through observation of the normal observation image on the monitor 30. Specifically, the operator operates the switch SW in the operation unit 10b of the electronic endoscope 10 to switch to the special observation mode.

  Then, the rotating plate 232 is inserted into the optical path of the white light emitted from the lamp 231, and the visible light transmission filter 232 a and the first excitation light transmission filter 232 b of the rotation plate 232 are respectively in the first field period and the second field. The white light is alternately inserted into the optical path in synchronization with the field period. As a result, white light and excitation light are alternately incident on the base end surface of the light guide 13, and white light and excitation light are alternately emitted from the distal end of the insertion portion 10a of the electronic endoscope 10. .

  In the first field period in which white light is irradiated into the body cavity, the body cavity is illuminated. After the illumination light reflected by the surface of the body cavity wall, the light transmitted through the objective lens 12 is transmitted through the excitation light removal filter 14 to remove the same wavelength component of about 400 nm to 450 nm as the excitation light. , And enters the imaging surface of the image sensor 15. At this time, an image (normal image) in the body cavity is formed on the imaging surface by the objective lens 12.

  On the other hand, in the second field period in which the excitation light is irradiated into the body cavity, the living tissue under the body cavity wall is excited to emit fluorescence, and the excitation light is reflected on the surface of the body cavity wall. Of the light including the fluorescence and the excitation light, the light transmitted through the objective lens 12 passes through the excitation light removal filter 14 to remove the same wavelength component of about 400 nm to 450 nm as the excitation light. That is, the excitation light and a part of the fluorescence are removed from the light including the fluorescence and the excitation light. The fluorescence that has passed through the excitation light removal filter 14 enters the imaging surface of the imaging element 15. At this time, an image in the body cavity (fluorescence image) is formed on the imaging surface by the objective lens 12.

  The normal image and the fluorescence image alternately formed on the imaging surface are picked up by the image pickup device 15, and their image signals are sequentially output to the image processing unit 24. In the image processing unit 24, the first-stage processing circuit 241 performs predetermined processing on the image signal, and in the first field period, each color component image data (normal image data) based on the normal image is stored in each color component memory 242r, 242g, 242b. The luminance component generation circuit 243 outputs the color component image data (fluorescence image data) based on the fluorescent image to the luminance component generation circuit 243 in the second field period.

  When the luminance component generation circuit 243 obtains each color component image data based on the normal image in the first field period, the luminance component generation circuit 243 converts it into luminance component image data and outputs it to the first luminance component memory 244a and the normal image brightness detection circuit 251. When each color component image data based on the fluorescent image is acquired in the second field period, it is converted into luminance component image data and output to the second luminance component memory 244b and the fluorescent image brightness detection circuit 252. Then, based on the luminance component image data in the first and second luminance component memories 244a and 244b, the affected area image data generation circuit 245 generates affected area image data.

  Then, after the affected area image data is added to the R component image data in each color component image data based on the normal image, each color component image data is converted into a video signal which is an image signal for monitor output in the post-processing circuit 248. This video signal is output to the monitor 30.

  For this reason, a special image generated based on the normal image and the fluorescent image is displayed on the monitor 30 as a color special observation image. The operator can identify the contours and irregularities of the body cavity wall while looking at the special observation image, and a biological body that emits relatively weak fluorescence due to the red spots in the image as spots or lumps. A group of tissues, that is, a site where a lesion such as a tumor or cancer is highly likely to be recognized can be recognized.

  At this time, in the normal image brightness detection circuit 251 of the dimming unit 25, the second dimming value is sequentially generated based on the Y component normal image data acquired from the image processing unit 24, and is sequentially generated. The amount of white light inserted into the optical path of the second excitation light transmission filter 234c of the diaphragm plate 234 is adjusted according to the amount of change in the light control value. For this reason, the brightness of the normal image based on the Y-component normal image data is maintained at a predetermined level by the second excitation light transmission filter 234c that substantially functions as a physical dimmer.

  Further, in the fluorescent image brightness detection circuit 252 of the dimming unit 25, the first dimming value is sequentially generated based on the Y component fluorescent image data acquired from the image processing unit 24, and the first dimming is sequentially generated. The amount of white light output from the lamp 231 in the second field period is adjusted according to the light value, and the charge accumulation period (the electronic shutter opening period) in each pixel of the image sensor 15 in the second field period. ) Is adjusted. For this reason, the brightness of the fluorescent image based on the Y component fluorescent image data is maintained at a predetermined level by a dimming method such as control of the output amount of white light or control of the open period of the electronic shutter.

  As described above, the brightness of the normal image and the brightness of the fluorescent image are individually adjusted appropriately, and as a result, the accuracy of the special image is further improved. Therefore, the operator can recognize the lesion site more accurately through the high-quality special observation image.

  As described above, in the electronic endoscope system of the present embodiment, an optical filter having the same transmission characteristics as the first excitation light transmission filter 232b for extracting excitation light from the lamp 231 is used as the second excitation light transmission filter 234c. In another special observation mode, the amount of white light as illumination light can be adjusted by inserting the second excitation light transmission filter 234c into the optical path of white light and adjusting the amount of insertion. As a result, the brightness of the normal image can be adjusted.

  At this time, the second excitation light transmission filter 234c continues to be inserted into the optical path of white light, but the amount of excitation light is not affected by the second excitation light transmission filter 234c. The two excitation light transmission filter 234c is used as a physical light control means for the illumination light.

  For the excitation light, a dimming method is adopted in which the output amount of the lamp 231 in the emission period of the excitation light is controlled or the open period of the electronic shutter of the image sensor 15 in the period is controlled. The brightness of the fluorescent image can be adjusted separately from the brightness of the normal image.

  In the electronic endoscope system according to the present embodiment, two through holes having the same shape are formed in the rotating plate 232 in the light source unit 23. However, the shape of the through hole is limited to this. It is not a thing. When the difference between the brightness of the normal image and the brightness of the fluorescent image is too wide and the brightness of the normal image and the fluorescent image cannot be balanced within the adjustment range described above, as shown in FIG. In addition, the size of the through hole in which the visible light transmission filter 232a is fitted may be halved.

External view of electronic endoscope system according to this embodiment Configuration diagram schematically showing inside of electronic endoscope and light source processor device Configuration diagram schematically showing the inside of the light source Front view of rotating plate Front view showing a state where the shielding part of the diaphragm plate blocks all white light Front view showing a state where the shielding part of the aperture plate blocks about half of the white light Explanatory drawing which shows the state by which the rotating plate was inserted in the optical path of white light Front view showing a state in which the second excitation light transmission filter blocks all white light Front view showing a state in which the second excitation light transmission filter blocks white light by about one-eighth Configuration diagram schematically showing the inside of the image processing unit and the light control unit Front view of a variation of the rotating plate

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic endoscope 11 Light distribution lens 12 Objective lens 13 Light guide 14 Excitation light removal filter 15 Image pick-up element 15a Signal line 15b Signal line 16 Driver 20 Light source processor apparatus 21 Timing control part 22 System control part 23 Light source part 231 Lamp 232 Rotation Plate 232a Visible light transmission filter 232b First excitation light transmission filter 233 First motor 233a Synchronization driver 234 Diaphragm plate 234c Second excitation light transmission filter 234d Shield part 235 Second motor 235a Driver for driving 236 Stage mechanism 237 Third motor 237a Moving driver 24 Image processing unit 241 Pre-processing circuit 243 Luminance component generation circuit 245 Affected image data generation circuit 246 Switch circuit 247 Adder 248 Post-processing circuit 25 Dimming 251 normal image brightness detecting circuit 252 fluorescence image brightness detecting circuit 30 monitors

Claims (2)

A tubular insertion portion for insertion into a body cavity;
An objective optical system that forms an image in the body cavity when the distal end of the insertion portion is inserted into the body cavity;
An imaging device that performs color imaging of an image of a body cavity formed by the objective optical system and outputs image data;
An illumination optical system that guides light from the proximal end of the insertion portion to the distal end and emits the light from the distal end; and
A white light source for emitting white light toward the illumination optical system;
A first excitation Okoshiko transmission filter for extracting the excitation light for exciting the biological tissue from the white light,
A second excitation light transmission filter having the same characteristics as the first excitation light transmission filter;
An insertion mechanism for alternately and repeatedly introducing the white light and the excitation light into the illumination optical system by periodically inserting the first excitation light transmission filter into the optical path of the white light at regular intervals. When,
Normal image data acquired from the imaging device during a first field period in which white light is introduced into the illumination optical system, and acquired from the imaging device during a second field period in which excitation light is introduced into the illumination optical system. An image processing unit that generates image data for displaying a special image showing a portion that can be estimated as an affected part based on the fluorescence image data,
A diaphragm mechanism for inserting the second excitation light transmission filter into the optical path of the white light;
The normal image data is acquired from the image processing unit, and the optical path of the white light of the second excitation light transmission filter by the diaphragm mechanism is set so that the brightness of the normal image based on the acquired normal image data becomes a predetermined level. An illumination light control unit for controlling the amount of insertion into,
The fluorescent image data is acquired from the image processing unit, and the white light from the white light source in the second field period is set so that the brightness of the fluorescent image based on the acquired fluorescent image data is at a predetermined level. An endoscope system comprising: an excitation light control unit that controls an output amount. The imaging device is an imaging device configured to change a charge accumulation period in each pixel in the second field period,
Fluorescence image data is acquired from the image processing unit, and the accumulation period in the second field period of the image sensor is controlled so that the brightness of the fluorescence image based on the acquired fluorescence image data becomes a predetermined level. The endoscope system according to claim 1, further comprising a fluorescence control unit.

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