JP4589607B2 - Optical imaging device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical imaging equipment for imaging biological tissue using a confocal optical system.
[0002]
[Prior art]
In recent years, an optical scanning type confocal microscope has been known as means for observing living tissue and cells with good resolution in the optical axis direction. However, in this case, a normal confocal microscope is large in size, and a sample is cut out and placed on the microscope for observation.
[0003]
In addition, a technique for reducing the size of the confocal microscope and guiding it to the digestive tract of a living organism for observation is proposed as a fine confocal microscope in, for example, Japanese Patent Laid-Open No. 9-230248.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-230248
[Problems to be solved by the invention]
However, in the above-described micro confocal microscope, in order to scan and irradiate a living tissue with a laser beam, for example, the irradiation laser beam is scanned inside the tip of an optical scanning probe inserted into a forceps channel or the like of an endoscope. Scanning mirrors are used, but the light quantity of the light source and the scanning response characteristics of the scanning mirror change due to secular change, etc., so conventionally, the light quantity and the scanning state of the mirror were observed using a test pattern before observation, There is a problem that it is necessary to adjust manually, and the work before observation becomes complicated.
[0006]
The present invention has been made in view of the above circumstances, and its object is to provide an optical imaging equipment capable of performing a simple and reliable automatic calibration of the confocal optical system.
[0007]
[Means for Solving the Problems]
An optical imaging apparatus according to an aspect of the present invention includes a light source that generates light, a probe unit that transmits and receives the light to a subject, and the subject that scans the light transmitted to the probe unit. Irradiating scanning means, driving means for driving and controlling the scanning means, light detecting means for detecting reflected light of the light reflected from the subject or scattered light of the light scattered from the subject, and the scanning A plurality of light receiving elements formed in a matrix array for detecting the light emitted from the means, and a timing of generating a drive signal of the driving means and a movement timing of the light detected by the plurality of light receiving elements Measuring means for measuring the scanning phase of the scanning means based on the time difference; and based on the scanning phase measured by the measuring means. Te, said light detecting means to signal processing a detection signal of the reflected light or scattered light is detected, the configured with an image generating device which generates a tomographic image of the subject, the.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0009]
1 to 4 relate to the first embodiment of the present invention, FIG. 1 is a configuration diagram showing the configuration of the optical imaging apparatus, FIG. 2 is a diagram showing the configuration of the calibration jig of FIG. 1, and FIG. FIG. 4 is a diagram showing a third photodetector provided in the calibration jig of FIG. 2, and FIG. 4 is a flowchart showing processing of a calibration operation by the CPU of FIG. 1.
[0010]
As shown in FIG. 1, the optical imaging apparatus 1 according to the present embodiment includes a confocal image generation apparatus 2, an optical scanning probe 3, and a calibration jig 4, and includes an optical scanning probe 3 and a calibration jig. The tool 4 is connected to the confocal image generating device 2 via the connectors 5 and 6, respectively, and the confocal image generated by the confocal image generating device 2 is displayed on the monitor 7 so that the confocal image can be observed. It has become.
[0011]
The confocal image generation apparatus 2 includes a light source 10 that generates laser light, a single mode fiber 11 that transmits laser light from the light source, and an optical transmission unit 13 that includes a four-terminal coupler 12 that bifurcates light in both directions. And the laser beam from the light source 10 is supplied from the first end 13 a of the optical transmission unit 13. In the optical transmission unit 13, the supplied laser light is transmitted to the second end 13 b provided inside the tip of the optical scanning probe 3 through the connector 5. The laser light emitted from the second end portion 13b is two-dimensionally scanned by the scanning optical system 14, and irradiates the observation site during observation.
[0012]
The return light from the observation site is incident on the second end portion 13 b by confocal action, and is transmitted to the third end portion 13 c of the optical transmission unit 13 through the connector 5 and the optical transmission unit 13. The light emitted from the third end 13 c is received by the first photodetector 15, and the detection signal detected by the first photodetector 15 is output to the signal processing circuit 16.
[0013]
In the signal processing circuit 16, the detection signal is sampled by the sampling signal from the CPU 17, pre-processed, etc., and the processed signal is output to the CPU 17, so that the CPU 17 generates a confocal image and displays the confocal image on the monitor 7.
[0014]
The scanning mirror 14 a constituting the scanning optical system 14 is driven by a scan driver 18, and the scan driver 18 is controlled by a driver control circuit 19.
[0015]
The driver control circuit 19 is controlled by the CPU 17, and a drive synchronization signal synchronized with the drive signal for driving the scanning mirror 14 a output from the scan driver 18 is fed back to the CPU 17, and the signal processing circuit 16 is driven by the control of the CPU 17. The detection signal is sampled based on the synchronization signal.
[0016]
A second photodetector 20 is provided at the fourth end 13 d of the optical transmission unit 13 so that the CPU 17 can monitor the amount of laser light emitted from the light source 10 based on the detection signal of the second photodetector 20. It has become.
[0017]
The calibration jig 4 includes a cable 21 connected via a connector 6 and a tip 22 provided at the tip of the cable 21 and attachable to the tip of the optical scanning probe 3, as shown in FIG. In addition, a third photodetector 23 is provided in the distal end portion 22, and by attaching the distal end portion 22 to the distal end of the optical scanning probe 3, the output emitted from the scanning optical system 14 as shown in FIG. The emitted light beam 24 is received by the light receiving unit 23 a of the third photodetector 23, and the CPU 17 can monitor the emitted light emitted from the scanning optical system 14 by the detection signal of the third photodetector 23 . .
[0018]
Further, the CPU 17 controls a light amount adjuster 25 that adjusts the light amount of the light source 10 based on detection signals of the second light detector 20 and the third light detector 23.
[0019]
In the present embodiment configured as described above, the light amount of the light source 10 can be appropriately adjusted by attaching the calibration jig 4 to the tip of the optical scanning probe 3 before confocal observation.
[0020]
Specifically, in a state where the calibration jig 4 is attached to the tip of the optical scanning probe 3, the CPU 17 controls the light amount adjuster 25 to emit the laser light of the light source 10 to the scanning optical system 14 with a default light amount. The amount of light emitted to the scanning optical system 14 is detected by the third photodetector 23, and the CPU 17 detects the amount of light, so that the amount of light supplied to the scanning optical system 14 becomes a predetermined amount of light. As described above, the light amount adjuster 25 can be controlled to emit laser light from the light source.
[0021]
In the present embodiment, the CPU 17 can monitor the optical connection state of the connector 5. That is, as shown in FIG. 4, the CPU 17 detects the light amount Wout of the light emitted from the tip of the optical scanning probe 3 in step S <b> 1 by the third photodetector 23. In step S <b> 2, the second light detector 20 detects the amount of light Winside from the light source 10 before entering the optical scanning probe 3. In step S3, a light amount difference ΔW (= Wout−Winside) between the light amount Wout and the light amount Winside is calculated. In step S4, it is determined whether ΔW exceeds a predetermined threshold value. If ΔW is equal to or smaller than the predetermined threshold value, step S5 is performed. In step S6, it is determined that the optical connection state of the connector 5 is normal, and the process is terminated. If ΔW exceeds a predetermined threshold value, it is determined in step S6 that the optical connection state of the connector 5 is abnormal. Display and finish the process.
[0022]
In the optical connection at the connector 5, even if the connector optical connection is normal, there is generally some light amount attenuation. However, when the connector optical connection is unstable, the light amount attenuation becomes large, and the light source 10 is only controlled by the third photodetector 23. The light quantity of the light source 10 can be adjusted only when the connector light connection is normal by combining the control by the second light detector 20 to properly determine the connector light connection state. Can be done.
[0023]
5 to 12 relate to the second embodiment of the present invention, FIG. 5 is a diagram showing a configuration of the calibration jig, and FIG. 6 shows a third photodetector provided in the calibration jig of FIG. FIG. 7 is a first diagram for explaining the calibration action by the CPU in the calibration jig of FIG. 5, and FIG. 8 is a second figure for explaining the calibration action by the CPU in the calibration jig of FIG. 9 is a third diagram for explaining the calibration action by the CPU in the calibration jig of FIG. 5, and FIG. 10 is a fourth figure for explaining the calibration action by the CPU in the calibration jig of FIG. 11 is a fifth diagram for explaining the calibration operation by the CPU in the calibration jig of FIG. 5, and FIG. It is a diagram showing a modified example of Jingu device.
[0024]
Since the second embodiment is almost the same as the first embodiment, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
[0025]
As shown in FIGS. 5 and 6, the configuration of the light receiving unit of the third photodetector 23 is different from that of the first embodiment, and the light receiving unit 23 b of the third photodetector 23 of the present embodiment includes a plurality of light receiving units. The CPU 17 is formed of light receiving elements formed in a matrix array, and the CPU 17 scans the light receiving states of the light receiving elements formed in the matrix array so that the amount of light supplied to the scanning optical system 14 is predetermined. The light amount adjuster 25 is controlled so as to obtain a light amount, and the laser light of the light source is emitted.
[0026]
That is, the CPU 17 uses a value obtained by multiplying the average value of the detection signals of the plurality of light receiving elements that have detected the incident light by the correction coefficient (variation correction of the light receiving elements) as the light amount of the light emitted to the scanning optical system 14. The adjuster 25 is controlled to emit the laser light from the light source 10.
[0027]
In the present embodiment, the optical scanning range and scanning phase of the scanning optical system 14 can be controlled.
[0028]
The optical scanning range of the scanning optical system 14 is detected by the CPU 17 by calculating the number in the vertical direction and the number in the horizontal direction of the plurality of light receiving elements that detect the incident light, and the CPU 17 controls the driver control circuit 19. The scan driver 18 is driven to set the scanning optical system 14 to an appropriate scanning range. FIG. 7 and FIG. 8 show examples of waveforms before correction when the number in the vertical direction and the optical scanning range in the horizontal direction are narrow, and FIGS. 9 and 10 show appropriate numbers after correction in the vertical direction and the horizontal direction. An example of a waveform when the optical scanning range is reached is shown.
[0029]
The scanning phase of the scanning optical system 14 is generated due to a delay in the operation response of the scanning mirror 14 a with respect to the drive signal of the scan driver 18. Therefore, based on the time difference between the generation timing of the drive synchronization signal from the driver control circuit 19 and the vertical movement timing and the horizontal movement timing of the plurality of light receiving elements that detect incident light with respect to the drive synchronization signal, the scanning optical system 14 The scan phase is calculated, and the sampling signal is output to the signal processing circuit 16 so as to oppose the operation response of the scanning mirror 14a, so that the detection signal is sampled in a state where the signal processing circuit 16 corrects the phase. FIG. 11 shows the phase states of the detection signal, the drive synchronization signal, and the sampling signal.
As described above, in this embodiment, in addition to the effects of the first embodiment, calibration of the optical scanning range and the scanning phase can be automatically performed.
[0030]
In the first and second embodiments, the calibration jig 4 including the cable 21 and the distal end portion 22 is connected to the confocal image generation apparatus 2 via the connector 6 to perform calibration. 12, the connector 6 is configured so that the tip of the optical scanning probe 3 can be mounted, and the light emitted from the scanning optical system 14 via the connector 6 is detected inside the confocal image generation device 2. A third photodetector 23 may be provided.
[0031]
FIGS. 13 to 20 relate to a third embodiment of the present invention, FIG. 13 is a diagram showing a configuration of a calibration jig, FIG. 14 is a diagram showing a reflecting member provided in the calibration jig of FIG. 15 is a view showing a display example of the confocal image of the reflecting member in FIG. 14 on the monitor, FIG. 16 is a flowchart showing the flow of light amount calibration processing using the reflecting member in FIG. 14, and FIG. 17 is the reflection in FIG. FIG. 18 is a diagram showing a confocal image of a member, FIG. 18 is a diagram showing a cell image to be compared with the confocal image of FIG. 17, and FIG. 19 is a flowchart showing a flow of scan phase calibration processing using the reflecting member of FIG. FIG. 20 is a diagram showing a two-dimensional correlation calculation in the process of FIG.
[0032]
Since the third embodiment is almost the same as the second embodiment, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
[0033]
Unlike the second embodiment, the configuration of the calibration jig 4 is different from that of the second embodiment. The calibration jig 4 of the present embodiment reflects the light emitted from the scanning optical system 14 as shown in FIG. The tip of the optical scanning probe 3 having a mounting portion 42 is configured to be mountable.
[0034]
The reflection member 41 of the calibration jig 4 of the present embodiment forms a matrix-like test pattern 43 having different reflectivities as shown in FIG. 14, and the light from the scanning optical system 14 is formed on the test pattern 43. The beam scans a predetermined observation range 44. The test pattern 43 is detected by the first photodetector 15 as described in the first embodiment.
[0035]
As a result, an image 43a of the test pattern 43 in the observation range 44 is displayed on the monitor 7 as shown in FIG.
[0036]
Further, the CPU 17 performs light amount calibration according to the flowchart (S11 to S13) shown in FIG. Further, the test pattern image 43a in the observation range 44 shown in FIG. 17 and the comparison cell image data stored in advance shown in FIG. 18 are used, and according to the flowchart (S14 to S20) shown in FIG. As shown in the second embodiment, the two-dimensional correlation calculation as shown is performed, the high reflection portion of the test pattern image 43a in the observation range 44 is extracted, and the extracted high reflection portion is used. Calibration of light quantity, optical scanning range, and scanning phase is automatically performed.
[0037]
Although the test pattern is extracted by two-dimensional correlation calculation, the present invention is not limited to this, and the test pattern may be extracted by contour extraction or other known image processing.
[0038]
As described above, also in the present embodiment, the same effects as those of the second embodiment can be obtained, and the calibration jig 4 can be configured more simply.
[0039]
FIGS. 21 to 24 relate to the fourth embodiment of the present invention, FIG. 21 is a diagram showing the configuration of the calibration jig, FIG. 22 is a diagram showing a cross section along line AA in FIG. 21, and FIG. FIG. 24 is a diagram showing a cross-sectional view taken along the line B-B in FIG. 23.
[0040]
Since the fourth embodiment is almost the same as the first and third embodiments, only different points will be described, and the same components are denoted by the same reference numerals and description thereof will be omitted.
[0041]
Unlike the second embodiment, the configuration of the calibration jig 4 is different from that of the second embodiment. The calibration jig 4 of the present embodiment has the test pattern described in the third embodiment as shown in FIGS. A slide plate 53 having a reflective surface 51 and an opening 52 is movable back and forth perpendicularly to the outgoing optical axis of the optical scanning probe 3.
[0042]
In the present embodiment, when the light amount is calibrated, as shown in FIGS. 21 and 22, the slide plate 53 is moved so that the opening 52 is aligned with the outgoing optical axis of the optical scanning probe 3, and the first embodiment is performed. Similarly to the embodiment, the light quantity of the light source 10 is adjusted by the detection signal of the third detector 23.
[0043]
When the optical scanning range and the scanning phase are calibrated, the slide plate 53 is moved so that the reflection surface 51 of the test pattern 43 is aligned with the outgoing optical axis of the optical scanning probe 3 as shown in FIGS. Similarly to the third embodiment, the high reflection portion of the test pattern image 43a is extracted, and the optical scanning range and the scanning phase are adjusted.
[0044]
As described above, in the present embodiment, in addition to the effects of the third embodiment, the light amount adjustment is performed by the detection signal of the third detector 21, so that more accurate light amount calibration can be performed.
[0045]
FIGS. 25 to 33 relate to the fifth embodiment of the present invention, FIG. 25 is a first flowchart showing the flow of image distortion calibration processing, and FIG. 26 is a first diagram for explaining the processing of FIG. 27 is a second diagram for explaining the processing of FIG. 25, FIG. 28 is a third diagram for explaining the processing of FIG. 25, FIG. 29 is a fourth diagram for explaining the processing of FIG. 25, and FIG. FIG. 31 is a second flowchart showing the flow of the image distortion calibration process following FIG. 25, and FIG. 32 is a test pattern calibrated by the processes of FIGS. 25 and 31. FIG. 33 is a diagram showing a test pattern image before calibration by the processing of FIGS. 25 and 31.
[0046]
The fifth embodiment is different from the third embodiment only in part of the operation of the CPU 17, and the configuration and other operations are the same as those of the third embodiment.
[0047]
The scanning of the scanning mirror 14a is performed by a drive signal from the scan driver, but differs from the waveform of the drive signal due to followability of the scan response of the scanning mirror 14a (for example, when the drive signal is a sine waveform, the scan response waveform is a sine waveform) Therefore, the image 43a obtained by photographing the test pattern 43 becomes a distorted image as shown in FIG. The CPU 17 of this embodiment calibrates this distortion.
[0048]
That is, as shown in FIG. 25, the mark (cell) position of the test pattern in the image is extracted by the two-dimensional correlation calculation in step S31 (see FIG. 26). Next, in step S32, the approximate line of the mark (cell) position in the row direction and the approximate line of the mark (cell) position in the vertical direction are calculated (see FIG. 27).
[0049]
Then, in step S33, an average straight line in the row direction and an average straight line in the vertical direction are calculated as shown in FIG. 28, and in step S34, as shown in FIG. 29, the mark position (example: X1, Y1) and the matrix A difference (eg, ΔX1, ΔY1) from the intersection of the approximate lines is calculated, and a slip difference correction table as shown in FIG. 30 is created in step S35.
[0050]
Then, image correction is performed using this slip difference correction table. Specifically, as shown in FIG. 31, confocal images are sampled in step S41 to obtain sampling data, and acquired in step S42. The coordinates of the sampling data are corrected by the seat difference correction table, the arrangement position on the image is adjusted, and the adjusted image is displayed on the monitor 7 in step S43.
[0051]
As described above, in this embodiment, in addition to the effects of the third embodiment, the distorted image shown in FIG. 33 can be calibrated to an image in which the distortion is corrected as shown in FIG.
[0052]
The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the scope of the present invention.
[0053]
【The invention's effect】
As described above, according to the present invention, there is an effect that the confocal optical system can be calibrated easily and reliably automatically.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of an optical imaging apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a calibration jig in FIG. 1. FIG. The figure which shows the 3rd photodetector provided in a fixture. FIG. 4 is a flowchart which shows the process of the calibration action by CPU of FIG. 1. FIG. 5 is the structure of the calibration jig | tool which concerns on the 2nd Embodiment of this invention. FIG. 6 is a diagram illustrating a third photodetector provided in the calibration jig of FIG. 5. FIG. 7 is a first diagram illustrating a calibration operation by the CPU in the calibration jig of FIG. 8 is a second diagram for explaining a calibration operation by the CPU in the calibration jig of FIG. 5. FIG. 9 is a calibration by the CPU in the calibration jig of FIG. FIG. 10 is a fourth diagram illustrating the calibration operation by the CPU in the calibration jig of FIG. 5. FIG. 11 is a calibration operation by the CPU in the calibration jig of FIG. FIG. 12 is a diagram showing a modification of the optical imaging apparatus in FIG. 1. FIG. 13 is a diagram showing a configuration of a calibration jig according to the third embodiment of the present invention. FIG. 15 is a view showing a reflection member provided in the calibration jig of FIG. 13. FIG. 15 is a view showing a display example of a confocal image of the reflection member of FIG. FIG. 17 is a flowchart showing a confocal image of the reflecting member in FIG. 14. FIG. 18 is a cell image to be compared with the confocal image in FIG. FIG. 19 is a flowchart showing the flow of scan phase calibration processing using the reflecting member of FIG. 14. FIG. 20 is a diagram showing two-dimensional correlation calculation in the processing of FIG. 19. FIG. The figure which shows the structure of the calibration jig | tool which concerns on 4 embodiment. FIG. 22 The figure which shows the AA line cross section of FIG. 21. FIG. 23 The arrangement | positioning state of the slide board of FIG. FIG. 24 is a cross-sectional view taken along line BB in FIG. 23. FIG. 25 is a first flowchart showing a flow of image distortion calibration processing according to the fifth embodiment of the present invention. FIG. 27 is a first diagram illustrating the processing of FIG. 25. FIG. 28 is a third diagram illustrating the processing of FIG. 25. FIG. 29 is a processing of FIG. The fourth figure explaining FIG. 31 is a second flowchart showing the flow of the image distortion calibration process following FIG. 25. FIG. 32 is a test pattern calibrated by the processes of FIGS. 25 and 31. FIG. 33 is a diagram showing an image of a test pattern before calibration by the processing of FIG. 25 and FIG. 31.
DESCRIPTION OF SYMBOLS 1 ... Optical imaging apparatus 2 ... Confocal image generation apparatus 3 ... Optical scanning probe 4 ... Calibration jig | tool 5,6 ... Connector 7 ... Monitor 10 ... Light source 11 ... Single mode fiber 12 ... 4-terminal coupler 13 ... Optical transmission part 14 ... Scanning optical system 15 ... first photodetector 16 ... signal processing circuit 17 ... CPU
DESCRIPTION OF SYMBOLS 18 ... Scan driver 19 ... Driver control circuit 20 ... 2nd photodetector 21 ... Cable 22 ... Tip part 23 ... 3rd photodetector 25 ... Light quantity adjuster

Claims (2)

A light source that generates light;
A probe unit that transmits and receives the light to the subject;
Scanning means for irradiating the subject with the light transmitted to the probe unit by scanning;
Driving means for driving and controlling the scanning means;
Light detection means for detecting reflected light of the light reflected from the subject or scattered light of the light scattered by the subject;
A plurality of light receiving elements formed in a matrix array for detecting the light emitted from the scanning means; a generation timing of a drive signal of the driving means and a movement timing of light detected by the plurality of light receiving elements Measuring means for measuring the scanning phase of the scanning means based on the time difference between
Based on the scan phase measured by the measurement unit, the detection signal of the reflected light or scattered light detected by the light detection unit is signal-processed to generate a tomographic image of the subject; and
An optical imaging apparatus comprising:   The optical imaging apparatus according to claim 1, further comprising a calibration jig that can be attached to a tip of the probe unit and includes a plurality of light receiving elements formed in the matrix shape.

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