JP5543254B2 - Laser scanning imaging device - Google Patents

Description

  The present invention relates to a laser scanning type imaging apparatus that scans and projects laser light onto an object to be imaged to construct a captured image of the object to be scanned.

  At present, representative examples of an eye imaging apparatus using a laser scanning technique include a confocal laser scanning ophthalmoscope (SLO; Scanning Laser Ophthalmoscope, hereinafter abbreviated as SLO) and an optical coherence tomograph (OCT: Optical Coherence Tomography, hereinafter referred to as OCT). (Refer to Patent Documents 1 to 3).

  This SLO is an apparatus mainly used for fluorescence imaging of the fundus oculi, and includes an illumination optical system that scans and projects laser light generated by a laser light emitting diode onto an object to be imaged, a laser beam reflected by the object to be imaged, A light receiving optical system that guides fluorescence from the fluorescent material to the light receiving element is provided. Further, the SLO has an image constructing unit that constructs an observation image for one frame of the object to be imaged from the output signal of the light receiving element for each scanning period of the laser beam by the scanner.

  In this fluorescence imaging of the fundus using SLO, a fluorescent agent such as ICG (Indocyanine Green) or sodium fluorescein is injected into a vein. Along with the injection of the fluorescent agent, the SLO irradiates the fundus of the patient with laser light having an excitation wavelength of the fluorescent agent to excite the fluorescent agent on the fundus and generate fluorescence from the fundus. In addition, the SLO receives fluorescence generated from the fundus blood vessel and performs fluorescence contrast.

  In addition, it is also used for autofluorescence imaging that captures the fluorescence of substances such as lipostin accumulated in diseased eyes and infrared light observation of the fundus. However, these fundus images can also be taken with a conventional fundus camera.

  By the way, since the amount of the fluorescent agent that flows into the fundus blood vessel during fluorescence imaging changes with time, the amount of fluorescence generated from the fundus blood vessel changes every moment. When blood leaks from the fundus blood vessel or there is a new blood vessel on the fundus, fluorescence is generated from the leaked portion or the new blood vessel over time.

  Therefore, the fundus camera continuously captures still images of the fundus blood vessel over time in order to inspect for blood leakage from the fundus blood vessel and the presence or absence of new blood vessels.

  However, as described above, since the fluorescence amount of the fluorescence generated from the fundus blood vessel changes every moment, in the fundus fluorescence photographing by the fundus camera, the exposure amount and the illumination light amount necessary for the next photographing are predicted and frequently adjusted. At present, it is difficult for an expert to take an image suitable for diagnosis.

  On the other hand, in SLO shooting, it is possible to shoot as a moving image by continuous scanning, and the moving image that is being observed in real time is directly captured as a moving image. But you can easily shoot.

  However, since SLO acquires information as a moving image, when a fundus image of one frame of moving image is taken out as a still image, the image becomes darker and more noisy than a fundus camera that originally captured a still image. This is because the exposure time per pixel is shorter than that of the fundus camera, which is unavoidable due to the principle of the apparatus.

  Therefore, in SLO, a plurality of fundus images are continuously captured, and the image signals of the captured fundus images are processed and synthesized by an averaging process or the like, thereby generating random noise such as speckle noise. By constructing a fundus image that has been removed, the image quality of the fundus image is improved.

  That is, in this averaging process, the fundus image with random noise is sampled n times as time passes, and the image signals of the fundus image obtained by the n times of sampling are added, and the added image signal is obtained. Even if it is 1 / n, there is no change in the magnitude of the image signal. However, random noise with random appearance does not appear in all of the image signals sampled n times, so the magnitude of the noise is smaller than the original noise and the S / N ratio is improved. . Based on this principle, random noise can be removed from the image signal of the fundus image in the addition averaging process.

  Also, in OCT that obtains interference from fundus reflection light and reference light and obtains a tomographic image by processing the interference signal, the tomographic image includes a lot of speckle noise. Has improved the quality.

  However, since the eyeball always continues a minute movement called fixation fixation micromotion, and the fundus to be imaged vibrates, the imaged fundus image is blurred. When a plurality of such fundus images are taken and the averaging process is performed, the position of the blood vessel shown in the fundus image is shifted from image to image, and the contrast of the blood vessel is rather deteriorated. End up.

  In addition, when magnifying and observing a minute area of the fundus, the resolution decreases due to the influence of the fixational micromotion. Further, in OCT, the scanning position on the fundus is shifted due to the patient's fixation fine movement, resulting in an image having a different tomographic position. Therefore, even if the averaging process is performed, the image quality cannot be improved.

  In order to prevent these, a tracking process is performed in which the line-of-sight direction of the eye to be examined is detected, and the movement of the fundus image due to the shift in the line-of-sight direction is removed from the detection result. In order to improve the tracking state, it is necessary to increase the sampling frequency for detecting the deviation and increase the control frequency.

  For example, when sampling and position correction by the scanner are performed 5 times per second (5 Hz), the amount of deviation (detection result) of the fundus image obtained by sampling is applied to position correction at the next sampling. Become. However, a new shift occurs due to 0.2 second fixation fine movement until correction is performed, and tracking is continued in a state where the shift amount does not converge.

  Therefore, if sampling and position correction are performed 10 times per second (10 Hz), the correction interval is 0.1 seconds, and the amount of deviation generated during that time is small, so the tracking state is closer to convergence. . If the distance between the two is made shorter and shorter, the fundus image being photographed can appear to stop even if the fixation is caused. However, even if the correction is performed in 0.1 seconds (10 Hz), the tracking shift amount cannot be brought close to convergence if the sampling for detecting the shift amount is 0.2 seconds (5 Hz). In other words, even if the correction interval is shortened, the tracking state is not improved unless the sampling interval is shortened.

  Several methods are already known for tracking, but a typical method is to rotate a small spot half the size of the nipple at high speed so that the signals detected at the front, rear, left and right positions are the same. A specific part tracking scanning method (see Patent Document 4) that always controls the scanner to capture the nipple at a predetermined position in the imaging area, or changes in feature points between images by detecting several feature points from the captured image. There is a change amount canceling scanning method in which the scanner is controlled so as to cancel the amount and the same area is always photographed.

JP 2008-295804 A JP 2008-155491 A JP 2008-267891 A US Pat. No. 5,943,115

  In the former specific part tracking scanning method, since the position of the nipple is sampled at a high frequency, tracking can be performed so that the screen appears to be stopped if the correction control of the scanner is also performed at a high frequency. However, since a module for searching the nipple is required in addition to the photographing optical system, the mechanism configuration is complicated and expensive.

  In the case of the latter change amount cancel scanning method, since the amount of deviation is detected from the captured screen, the sampling frequency is the same as the frame rate of the captured image. For this reason, even if correction control is performed at a high frequency, the tracking state is such that the screen appears to shake at the sampling frequency.

  Further, when trying to obtain a high resolving power with an SLO captured image, since the scan pitch is made finer, the imaging time is extended and the frame rate is decreased. As a result, the tracking state becomes worse. However, this method does not require a new mechanism configuration for detecting the amount of deviation, and the device can be configured more simply and cheaper than the former.

  In addition, when shooting a high-resolution image with SLO, the video frame rate is low because the scanning pitch is fine, so the video screen in this state is taken on the top and bottom (or left and right) of the image. The time difference of becomes larger. This makes it difficult to adjust the focus and alignment uniformly throughout the image.

  Thus, in the SLO configured to detect the shift amount from the photographed image and perform tracking, the tracking sampling frequency cannot be made higher than the photographing frame rate, and the tracking state is not good.

  Further, in the eye photographing apparatus using the laser scanning technique as described above, it is difficult to obtain the original effect of image processing for improving the still image quality. In addition, it is difficult to adjust the focus and alignment when shooting a moving image with high resolution.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a laser scanning type imaging apparatus capable of easily adjusting the focus and alignment and improving the tracking state of moving images for imaging.

In order to achieve this object, a laser scanning type photographing apparatus of the present invention comprises a laser light generating means for emitting laser light for photographing, and a scanning means for scanning the laser light. an illumination optical system for scanning projecting a laser beam, said light receiving optical system for guiding the light receiving means receives the reflected light and or fluorescence from the imaging target portion, an output of said light receiving means of said laser beam by said scanning means An image constructing unit configured to construct an observation image of the imaging target unit from a signal; and a control circuit configured to control operation of scanning of the scanning unit. Moreover, the control circuit, by actuating controls the scanning means in a scanning pattern of a plurality of scan group that different for each scanning cycle of the laser beam in order for each of the scan group, by different scanning patterns of said laser beam The moving image of the object to be imaged is constructed in order by the image construction unit for each scanning group, and different moving image images acquired in the plurality of scanning groups are combined, thereby One moving image is formed. Further, the control circuit controls the scanning unit to acquire an image of the object to be imaged as a reference image by scanning with a normal scanning pattern, and thereafter, the moving image of the object to be imaged is different from the plurality of images. When sequentially acquiring a scan pattern in a scan group, the moving image acquired in a scan group before the scan group that is being scanned while scanning the portion to be imaged in one of the plurality of scan groups The amount of deviation between the image and the reference image is detected, and based on the amount of deviation, correction processing of the scanning start position of the scanning group after the scanning group being scanned is executed .

  According to this configuration, it is possible to easily adjust the focus and alignment, and to improve the tracking state of the moving image for shooting.

1 is a photographing optical system of a laser scanning ophthalmoscope as a laser scanning photographing apparatus according to the present invention. It is the schematic which shows the control circuit of the laser scanning ophthalmoscope of FIG. FIG. 3 is a detailed diagram of the image data processing circuit of FIG. 2. It is explanatory drawing of the laser scanning (laser scan) of the fundus by the laser scanning ophthalmoscope of FIG. FIG. 3B is a schematic explanatory diagram of an image memory that stores image data obtained by the laser scanning of FIG. 3A. It is explanatory drawing which shows the example of a scan by the scanning group 1. FIG. 10 is an explanatory diagram illustrating an example of scanning by a scanning group 2. FIG. It is scanning explanatory drawing when the scanning group 1 of FIG. 4A and the scanning group 2 of FIG. 4B were synthesize | combined. It is explanatory drawing when the fundus image by the scanning group 1 of FIG. 4A and the fundus image by the scanning group 2 of FIG. 4B are synthesized. It is explanatory drawing which shows the scanning position when there are three scanning groups. It is explanatory drawing which shows the scanning position when there are four scanning groups. It is explanatory drawing of the shift correction process accompanying the scanning of FIG. It is explanatory drawing of the deviation | shift amount with respect to the reference | standard image of the scanning group 1 accompanying a fixation fine movement. It is explanatory drawing of the deviation | shift amount with respect to the reference | standard image of the scanning group 2 accompanying a fixation fine movement. It is explanatory drawing which shows the other example of the deviation | shift amount detection for a shift correction process.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Constitution]
FIG. 1 shows an example of an imaging optical system of a laser scanning ophthalmoscope SLO as a laser scanning imaging apparatus according to the present invention. The photographing optical system includes an illumination optical system (illumination light projection optical system) 1 and a light receiving optical system 2.
<Illumination optical system 1>
The illumination optical system 1 includes an illumination light generation unit 3 that is laser light generation means, and a common optical system 4 that is shared with the light receiving optical system 2.
・ Illumination light generator 3
The illumination light generation unit 3 includes a first light source 5, a second light source 6, a dichroic mirror (first light separation means) 7, a relay lens 8, a diaphragm 9, and a relay lens 10.

  The first light source 5 generates infrared fluorescence excitation illumination light (laser light) having an excitation wavelength λ1 of 790 nm for infrared fluorescence excitation, and ICG (Indocyanine Green) is generated by the infrared fluorescence excitation illumination light. Infrared light emitting diodes that generate fluorescence from the ICG are used as light sources for exciting infrared fluorescence. The second light source 6 generates visible fluorescence excitation illumination light (laser light) having an excitation wavelength λ2 for excitation of visible fluorescence of 473 nm, and excites sodium fluorescein with this illumination light for excitation of visible fluorescence. A visible light emitting diode that generates fluorescence from sodium fluorescein is used as a light source for exciting visible fluorescence.

  The dichroic mirror 7 transmits an illumination light beam having an infrared fluorescence excitation wavelength (λ = 790 nm) and reflects an illumination light beam having a visible fluorescence excitation wavelength (λ = 473 nm).

  The illumination light beam having the infrared fluorescence excitation wavelength (λ = 790 nm) emitted from the first light source 5 passes through the dichroic mirror 7 and then passes through the relay lens 8, the diaphragm 9, and the relay lens 10, 2) is guided to the common optical system 4 through the dichroic mirror 11. At this time, the diaphragm 9 converts the illumination light beam from the first light source 5 into a laser spot light having a set diameter.

  The visible fluorescence excitation wavelength (λ = 473 nm) emitted from the second light source 6 is reflected by the dichroic mirror 7 and then guided to the dichroic mirror 11 by the relay lens 8, the diaphragm 9 and the relay lens 10. The light passes through the dichroic mirror 11 and is guided to the common optical system 4. At this time, the diaphragm 9 converts the illumination light beam from the second light source 6 into a laser spot light having a set diameter.

Furthermore, the dichroic mirror 11 reflects infrared light and visible light that are incident on the common optical system 4 and guided from the eye E to be examined.
・ Common optical system 4
The common optical system 4 includes a relay lens 12, a resonant mirror (horizontal scanner or horizontal scanning means) 13, relay lenses 14 and 15, a galvano mirror (vertical scanner or vertical scanning means) 16, pupil correction mirrors 17 and 18, and a relay lens. 19, 20, half mirrors 21, 22, focusing lens 23, half mirrors 24 and 25, and objective lens 26.

  Moreover, the pupil correction mirrors 17 and 18 are provided so as to be integrally movable and adjustable in the optical axis O direction (left and right direction in FIG. 1) of the focusing lens 23 and the objective lens 26. This movement adjustment is performed by the correction drive motor M1 in FIG. A pulse motor or the like is used as the correction drive motor M1, but a motor other than the pulse motor may be used. The focusing lens 23 is provided so as to be movable and adjustable in the optical axis direction by a focusing drive motor M2 such as a pulse motor. A known external photographing device (not shown) for taking out and photographing the reflected light beam from the fundus image through the half mirror 22 can also be provided.

  The infrared fluorescent excitation illumination light and the visible fluorescent excitation illumination light transmitted through the dichroic mirror 11 are spot illumination lights having a diameter set by the diaphragm 9, and the relay lens 12, resonant mirror (horizontal scanning means) ) 13, relay lenses 14 and 15, galvanometer mirror (vertical scanning means) 16, pupil correction mirrors 17 and 18, relay lenses 19 and 20, half mirrors 21, 22, focusing lens 23, and half mirrors 24 and 25 It is guided to the objective lens 26 and projected from the objective lens 26 onto the eye E.

  At this time, the resonant mirror 12 horizontally scans the spot illumination light, and the galvano mirror 16 vertically scans the spot illumination light.

  The illumination optical system 1 includes an internal fixation light source 27 for fixing the eye to be examined, an alignment light source 28, and a split light beam projection optical system 29 for focusing.

  The fixation light beam from the internal fixation light source 27 is guided to the objective lens 26 via the relay lens 27a, the half mirrors 21, 22, the focusing lens 23, and the half mirrors 24, 25, and is then examined from the objective lens 26 to the eye E. Is projected onto the fundus oculi Er. The visual direction of the eye E is fixed by making the eye to be visually recognized by the fixation light beam. Since a known configuration can be adopted for this configuration, detailed description thereof is omitted.

  The alignment light beam from the alignment light source 28 is guided to the objective lens 26 through the half mirrors 24 and 25, projected from the objective lens 26 onto the cornea of the eye E, and the alignment bright spot is projected onto the cornea of the eye E. An image is formed. Since a well-known configuration can be adopted for this configuration, a detailed description thereof is omitted.

Further, the split luminous flux from the split luminous flux projection optical system 29 is guided to the objective lens 26 through the half mirror 25, projected from the objective lens 26 onto the fundus Er of the eye E, and split onto the fundus Er of the eye E to be examined. An image is formed. The split image formed on the fundus Er of the eye E to be examined is matched by driving and adjusting the focusing lens 23 in the optical axis direction, and an APD (light receiving element) to be described later is focused on the fundus Er of the eye E to be examined. Can be made. Since this split beam projection optical system 29 can employ a known technique, a detailed description thereof will be omitted.
<Light receiving optical system 2>
The light receiving optical system 2 includes a common optical system 4 and a light receiving unit 30 as light receiving means. The light receiving unit 30 includes a diaphragm 31, a relay lens 32, and third and fourth dichroic mirrors (third and fourth light separating means) 33 and 34.

  The reflected light reflected by the eye E and the fluorescence generated by the eye E enter the common optical system 4 and are guided to the dichroic mirror 11 through the common optical system 4, and then are reflected by the dichroic mirror 11. The light is reflected and guided to the light receiving unit 30. The light guided to the light receiving unit 30 is guided to the third dichroic mirror 33 through the diaphragm 31 and the relay lens 32.

  The third dichroic mirror 33 transmits a light beam having a wavelength shorter than 820 nm and reflects a light beam having a wavelength of 820 nm to 900 nm. The fourth dichroic mirror 34 transmits a light beam having a wavelength of 450 nm to 700 nm and reflects a light beam having a wavelength of 700 nm to 820 nm.

  The light receiving unit 30 includes first to third APDs (avalanche photodiodes) 35, 36, and 37 as first to third light receiving elements (light receiving means). The first APD 35 receives a light beam with an infrared wavelength of 820 nm to 900 nm, the second APD 36 receives a light beam with an infrared wavelength of 700 nm to 820 nm, and the third APD 37 has a visible wavelength of 450 nm to 700 nm. Receives light flux.

When the photographing optical system (illumination optical system 1, light receiving optical system 2, etc.) of FIG. 1 is aligned with respect to the eye E, the optics of the photographing optical system (illumination optical system 1, light receiving optical system 2 etc.) The conjugate position between the member and the fundus Er of the eye E is indicated by a black circle, and the conjugate position between the optical member of the imaging optical system (illumination optical system 1, light receiving optical system 2, etc.) and the pupil Ep of the eye E is indicated by a white circle. It was.
<Image Data Processing Circuit 38>
Further, the laser scanning ophthalmoscope has the image data processing circuit 38 on the ophthalmoscope (device main body) side shown in FIG. 2 as a control circuit.

  The image data processing circuit 38 includes a first image construction unit 39 that is a first image signal processing circuit, a second image construction unit 40 that is a second image signal processing circuit, and a third image signal processing. It has the 3rd image construction part 41 which is a circuit. Further, the image data processing circuit 38 has a mirror drive control circuit 42 as shown in FIG.

1 and 2, the image signal from the first APD 35 is input to the first image construction unit 39, and the image signal from the second APD 36 is input to the second image construction unit 40. The input image signal from the third APD 37 is input to the third image construction unit 41.
(A). First image construction unit 39
As shown in FIG. 3, the first image construction unit 39 includes an ADC (analog / digital converter) 43 to which an image signal from the first APD 35 is input, and a digital image signal converted into a digital signal by the ADC. And an arbitration circuit (a write / read / stop control adjusting unit, that is, a write / read / stop control adjusting circuit) that controls the image memory 44 to write and read image data. ) 45.

  The first image construction unit 39 includes a write address generation unit (write address generation circuit) 46 that generates a write address of image data and a read address generation unit (read address generation circuit) 47. The write address generated by the write address generation unit 46 and the read address generated by the read address generation unit 47 are input to the arbitration circuit 45, and image data is written to the image memory 44 by the arbitration circuit 45. The image data written (stored) in the image memory 44 is used for reading.

  Further, the first image construction unit 39 includes a synchronization signal generation unit (synchronization signal generation circuit) 48.

The first image construction unit 39 has a PC interface 49 for external connection. The PC interface 49 is connected to an image processing circuit (not shown) of the personal computer 50 shown in FIG.
Mirror drive control circuit 42
As shown in FIG. 3, the mirror (scanner) drive control circuit 42 includes a resonant mirror (horizontal scanner) drive circuit 51, a galvano mirror (vertical scanner) drive circuit 52, a row counter 53, and a pixel clock generation circuit. 54 and a column counter 55.

The resonant mirror drive circuit 51 outputs a horizontal drive signal to cause the resonant mirror 13 to vibrate and scan in the horizontal direction at high speed, and the galvano mirror drive circuit 52 outputs a vertical drive signal to rotate the galvano mirror 16 in the vertical direction. It is designed to drive.
・ Low counter 53
The row counter 53 inputs a vertical drive signal to the galvano mirror drive circuit 52 for each horizontal scan of the resonant mirror 13 in the horizontal direction, and counts the number of horizontal scans of the resonant mirror 13 in the horizontal direction.

  In addition, the value of the row counter 53 is not simply increased sequentially, but as shown in the laser scanning pattern example of FIG. 4, the scanning of each scanning pattern is performed with two or more scanning patterns that do not scan the same place. Is performed individually for each cycle, and is added with a large value, and when scanning for one cycle is completed, it is decremented to a position slightly shifted from the head, and row addition for the next cycle is resumed.

When a vertical drive signal is input from the row counter 53 to the galvano mirror drive circuit 52, the galvano mirror drive circuit 52 rotates the galvano mirror 16 by a predetermined set angle in the vertical direction.
Pixel clock generation circuit 54
The resonant mirror 13 performs high-speed scanning in the horizontal direction and does not stop. For this reason, a synchronous pulse is output from the resonant mirror drive circuit 51 when a specific position is scanned. When the synchronizing pulse is output, the pixel clock PCL for determining the dot position is output from the pixel clock generation circuit 54 and input to the column counter 55.

  Since the angular scanner has an angular velocity given by ω = COS (ω ′ · t), the resonant scanner moves at a low speed at the end of the scanning range and moves at a high speed at the center. For this reason, the pixel clock generation circuit 54 is a circuit for outputting a pixel clock PCL having a wide pulse interval in the peripheral portion and a narrow pulse interval in the vicinity of the central portion in order to keep the sample points at equal intervals.

The column counter 55 is a counter that holds the current horizontal position, and is used for address calculation when writing pixel data to the image memory 44. As described above, the operation of the circuit for positioning in the horizontal direction is started by the synchronization signal output from the resonant mirror driving circuit 51. At the same time, the operation of the row counter 53 for positioning the galvanometer mirror that performs scanning in the vertical direction is started. The value is also updated.
・ Column counter 55
The column counter 55 is a counter that holds the current horizontal position, and is used for address calculation when writing pixel data to the image memory 44. As described above, the operation of the circuit for positioning in the horizontal direction is started by the synchronization signal output from the resonant mirror driving circuit 51. At the same time, the operation of the row counter 53 for positioning the galvanometer mirror that performs scanning in the vertical direction is started. The value is also updated.
(B). Second and third image construction units 40 and 41
Since the configurations of the second and third image construction units 40 and 41 have the same configuration as that of the first image construction unit 39, description thereof will be omitted.

  The image data processing circuit 38 is controlled by the control circuit 60 shown in FIG. The control circuit 60 starts operation by turning on the power switch 61 to generate a control clock, and inputs the control clock to the image data processing circuit 38. In addition, a mode changeover switch 62 is connected to the control circuit 60. With this mode changeover switch 62, the control circuit 60 can be switched between the infrared fluorescent photographing mode and the visible fluorescent photographing mode. The control circuit 60 is set so as to be in either the infrared fluorescent photographing mode or the visible fluorescent photographing mode when the power is turned on by turning on the power switch 61. Usually, the control circuit 60 is set to the infrared fluorescent photographing mode. Keep it. The control circuit 60 turns on the first light source 5 in the infrared fluorescent photographing mode and turns on the second light source 6 in the visible fluorescent photographing mode. Further, the mode switching operation can be performed by the personal computer 50.

Further, the control circuit 60 controls the correction drive motor M1 and the focus drive motor M2. Further, when the control circuit 60 is turned on, the internal fixation light source 27, the alignment light source 28, and the light source 29a of the split beam projection optical system 29 are turned on.
[Action]
Next, control by the control circuit 60 and the image data processing circuit 38 of the laser scanning ophthalmoscope having such a configuration will be described.
(1). Basic Control Operation for Shooting The control circuit 60 operates when the power switch 61 is turned on, and operates as an anterior ocular segment illumination light source (not shown), first and second light sources 5 and 6, an internal fixation light source 27, an alignment light source. 28, the light source 29a of the split beam projection optical system 29 is turned on.
(I). Alignment By turning on the anterior ocular segment illumination light source (not shown), the anterior segment of the eye E is illuminated by the anterior segment illumination light source, and the reflected light beam from the anterior segment of the eye E is not illustrated. The anterior segment image of the eye E is captured by a photographing optical system or the like and displayed on a monitor (display device such as a liquid crystal display) (not shown). Since this configuration is well known, illustration and detailed description are omitted. Moreover, the control circuit 60 turns on the alignment light source 28 during this anterior segment illumination.

  As a result, the alignment light beam from the alignment light source 28 is guided to the objective lens 26 via the half mirrors 24 and 25, projected from the objective lens 26 onto the cornea of the eye E, and aligned to the cornea of the eye E. Form an image. The optical axis of the objective lens 26 is adjusted by moving the laser scanning ophthalmoscope (device main body) up and down and left and right so that the alignment bright spot image is positioned at the center of the pupil of the eye E. It is made to coincide with the optical axis of E. In addition, along with this, the laser scanning ophthalmoscope (apparatus body) is moved and adjusted to adjust the working distance of the laser scanning ophthalmoscope (apparatus body), that is, the working distance of the objective lens 26 with respect to the eye E. .

  Although the alignment of the objective lens 26 with respect to the eye E by such movement adjustment can be performed manually or automatically, a well-known configuration can be adopted as a configuration for automatically detecting the alignment state and performing alignment.

When the alignment of the objective lens 26 with the eye E is completed, the internal fixation light source 27 and the split index (not shown) of the split light beam projection optical system 29 become conjugate with the fundus Er of the eye E.
(Ii). Fixation control and focusing control of eye E In this state, fixation light (fixation target) from internal fixation light source 27 is relay lens 27a, half mirrors 21, 22, focusing lens 23, and half mirrors 24 and 25. , And projected onto the fundus Er of the eye E through the objective lens 26. Thereby, the fixation light from the internal fixation light source 27 is visually recognized by the eye E, and the direction of the eye E is fixed.

  At this time, the split index (split index beam) used for the focusing operation is projected from the focusing split beam projection optical system 29 onto the fundus Er of the eye E through the half mirror 25 and the objective lens 26.

  On the other hand, the split index light beam from the split light beam projection optical system 29 is guided to the half mirror 22 through the objective lens 26, the half mirrors 25 and 24, and the focusing lens 23, and the half mirror 22 uses a CCD ( 2D light receiving element).

  An image signal is output from the CCD (not shown) and input to the control circuit 60. Based on the image signal input to the control circuit 60, the fundus image is displayed together with the split index image (not shown) of the personal computer 50. Displayed on a monitor such as a liquid crystal display).

  The control circuit 60 controls the focusing drive motor M2 based on the image signal (output signal) from the CCD so that the split index images displayed on the display device (not shown) of the personal computer 50 coincide with each other. The focal lens 23 is moved and adjusted in the optical axis direction. Since this focusing control is well known, its detailed description is omitted.

  When the focusing operation is completed, the first and second light sources 5 and 6 and the first to third APDs 35 to 37 are substantially conjugate with the fundus Er of the eye E.

Further, the control circuit 60 moves and adjusts the pupil correction mirrors 17 and 18 in the direction of the optical axis O of the focusing lens 23 and the objective lens 26 (left and right direction in FIG. 1) by driving control of the correction drive motor M1. This movement adjustment corrects the difference in length of the wavelength λ of the spot illumination light projected onto the eye E, and conjugates the pupil Ep of the eye E with the resonant mirror 13 and the galvanometer mirror 16. Since this control is well known, its detailed description is omitted.
(Iii). As described above, when the power switch 61 is turned on, the control circuit 60 starts a control operation and the laser scanning ophthalmoscope is activated. As a result, the control circuit 60 generates a control clock and inputs the control clock to the image data processing circuit 38.

  The image data processing circuit 38 operates in accordance with the control clock input from the control circuit 60 and starts the operations of the resonant mirror driving circuit 51 and the galvano mirror 16. The resonant mirror drive circuit 51 outputs a horizontal drive signal to cause the resonant mirror 13 to vibrate and scan in the horizontal direction at a high speed, and the galvano mirror drive circuit 52 outputs a vertical drive signal to rotate the galvano mirror 16 in the vertical direction. Drive. Details of the operation control of the image data processing circuit 38, the resonant mirror 13 and the galvanometer mirror 16 will be described later.

  When the infrared fluorescent photographing mode is prioritized, the control circuit 60 turns on the first light source 5 when the power switch 61 is turned on. In this case, illumination light (infrared light) having an infrared fluorescence excitation wavelength having a wavelength λ of 790 nm can be emitted from the first light source 5. When the visible fluorescent photographing mode is prioritized, the control circuit 60 turns on the second light source 6 when the power switch 61 is turned on. In this case, illumination light (visible light) having a visible fluorescent excitation wavelength having a wavelength λ of 473 nm is emitted from the second light source 6. Normally, the infrared fluorescent photographing mode is set with priority.

  Illumination light (illumination light beam) emitted from the first light source 5 or the second light source 6 passes through the dichroic mirror 7 and then passes through the relay lens 8, the diaphragm 9, and the relay lens 10, and the dichroic mirror (second light beam). The light separating means 11) is transmitted through the dichroic mirror 11 and guided to the common optical system 4. At this time, the diaphragm 9 turns the illumination light beam from the first light source 5 into spot light (spot illumination light) having a set diameter.

  The spot illumination light transmitted through the dichroic mirror 11 is projected onto the eye E through the common optical system 4. That is, the spot illumination light is relay lens 12, resonant mirror (horizontal scanning means) 13, relay lenses 14 and 15, galvano mirror (vertical scanning means) 16, pupil correction mirrors 17 and 18, relay lenses 19 and 20, and half mirror. 21, 22 are guided to the objective lens 26 through the focusing lens 23 and the half mirrors 24, 25, projected from the objective lens 26 onto the eye E, and the eye E is scanned and illuminated with spot illumination light.

  In this projection, the conventional spot illumination light (laser illumination light) is normally scanned by one pitch (diameter of spot illumination light) in the vertical direction by the galvano mirror 16 every time one horizontal scan is performed by the resonant mirror 13. Is done. However, in the present embodiment, there are actually a plurality of laser scanning patterns that do not scan the same place as will be described later. The number of scannings of the spot illumination light in the vertical direction by the galvanometer mirror 16 is executed by the galvanometer mirror driving circuit 52 as many times as the number of horizontal scanning lines in the vertical direction is obtained for one frame.

A well-known operation control program is used for such basic control of the resonant mirror 13 and galvanometer mirror 16, that is, basic control of scanning of spot illumination light. The present embodiment is improved as described later based on such basic control of scanning of spot illumination light.
(IV). Outline of image construction of fundus image In the case of the infrared fluorescence imaging mode, the scanning illumination for the eye E with spot illumination light as in (iii) is performed by infrared fluorescence excitation with the wavelength λ of 790 nm from the first light source 5. This is performed with illumination light having a wavelength (infrared light). Therefore, in the infrared fluorescence imaging mode, ICG (Indocyanine Green) is injected (intravenous injection) into the vein of the subject (patient), and the eye E is scanned and illuminated with spot illumination light having an infrared fluorescence excitation wavelength. Then, the fluorescent agent flowing in the fundus blood vessel of the eye E is excited and generates fluorescence (emits light). The wavelength λ of this fluorescence is 826 nm or more.

  In the case of the visible fluorescent photographing mode, the scanning illumination for the eye E with the spot illumination light as in (iii) is the illumination light (visible fluorescence excitation wavelength) having a wavelength λ of 473 nm from the second light source 6. Visible light). Therefore, in the visible fluorescence imaging mode, when fluorescein sodium is injected (intravenous injection) into the vein of the subject (patient) and the eye E is scanned and illuminated with spot illumination light having a visible fluorescence excitation wavelength, the eye E The fluorescent agent flowing in the fundus blood vessels of the eye is excited to generate fluorescence (emission). The wavelength λ of this fluorescence is 513 nm.

  Then, in accordance with the scanning illumination of the eye E with the spot illumination light as in (iii), the fundus image light flux (reflected light or reflected light and fluorescence) from the fundus Er of the eye E is the common optical system described above. 4 to the dichroic mirror 11. The light beam for the fundus image is reflected by the dichroic mirror 11 and then guided to the dichroic mirror 33 through the relay lens 32.

  The fundus image luminous flux having a wavelength λ of 820 to 900 nm is reflected by the third dichroic mirror 33 and received by the first APD 35, and the rest passes through the third dichroic mirror 33.

  The fundus image light flux that has passed through the third dichroic mirror 33 is reflected by the fourth dichroic mirror 34 with a wavelength λ of 700 to 820 nm, and is received by the second APD 36, and the remainder is the fourth. The light passes through the dichroic mirror 34. The fundus image light flux transmitted through the fourth dichroic mirror 34 is received by the third APD 37 having a wavelength λ of 450 to 700 nm.

Image signals are output from the first to third APDs 35 to 37, and the image signals are input to the image data processing circuit 38. The image data processing circuit 38 constructs a fundus image (ophthalmic image) based on the image signals input from the first to third APDs 35 to 37.
(2). Details of image construction in the embodiment Since the image data processing circuit 38 performs the same processing on the image signal from the first to third APDs 35 to 37, only the processing of the image signal from the first APD 35 will be described. Description of the processing of the image signals from the second and third APDs 36 and 37 is omitted.
[I]. Basic Storage Control of Image Data Here, in describing the processing of the image signal from the first APD 35, as shown in FIG. 3A, horizontal scanning is performed with the spot illumination light (spot laser light) described above. The position in the vertical direction is defined as the vertical scanning position Pvi, the position in the horizontal direction that is horizontally scanned by the spot illumination light (spot laser light) is defined as the horizontal scanning position Phj, and the spot illumination light at the horizontal scanning position Phj at the vertical scanning position Pvi. Let Pij be the position of. Further, as shown in FIG. 3B, the address for the vertical scanning position of the image memory 44 is set to Mvi, the address for the horizontal scanning position of the image memory 44 is set to Mhj, and for storing actual image dot data. The address is Mij.

  As described above, when the image data processing circuit 38 is operated by the control circuit 60, the pixel clock PcL for determining the dot position is output from the pixel clock generation circuit 54 of the image data processing circuit 38. The pixel clock PcL is input to the ADC 43 corresponding to the column counter 55 and the first APD 35.

  The column counter 55 outputs a vertical position signal Svi of the vertical scanning position Pvi in the current vertical direction that is horizontally scanned by spot illumination light (spot laser light), and the vertical position signal Svi is input to the arbitration circuit 45. Is done. The arbitration circuit 45 receives the vertical position signal Svi and controls to store the image dot data at the address Mij in the image memory 44.

  On the other hand, the image signal from the first APD 35 is input to the ADC 43 corresponding to the first APD 35 of the image data processing circuit 38. The ADC 43 performs A / D conversion (analog / digital conversion) on the image signal from the first APD 35 based on the pixel clock PcL, and converts the converted digital image dot data to the address Mij instructed by the arbitration circuit 45. Remember me.

Basically, digital image dot data based on the image signal from the first APD 35 is stored in the image memory 44 in this way.
[II]. Actual processing control of image data 1
Incidentally, the resonant mirror drive circuit 51 does not stop the vibration of the resonant mirror 13 by causing the resonant mirror 13 to vibrate at high speed in the horizontal direction. As a result, the spot illumination light is scanned at high speed in the horizontal direction by the resonant mirror 13 and does not stop.

  For this reason, a synchronous pulse is output from the resonant mirror drive circuit 51 when a specific position is scanned. When the synchronization pulse is output, a pixel clock PcL for determining the dot position is output from the pixel clock generation circuit 54 and input to the column counter 55.

  Further, since the vibration of the resonant mirror 13 is given by the angular velocity ω = COS (ω ′ · t), the spot illumination light is scanned at a low speed at the end of the scanning range of the spot illumination light by the resonant mirror 13 and is scanned at a high speed at the center. To be. For this purpose, the pixel clock PcL is slow at the end of the scanning range of the spot illumination light by the resonant mirror 13 and fast at the center. That is, the pixel clock generation circuit 54 outputs a pixel clock PcL having a wide pulse interval in the peripheral portion and a narrow pulse interval in the vicinity of the central portion in order to keep the sample points at equal intervals.

  Further, the column counter 55 is a counter that holds the current horizontal position, and is used for address calculation when writing pixel data to the image memory 44. As described above, the operation of the circuit for positioning in the horizontal direction is started by the synchronization signal output from the resonant mirror driving circuit 51. At the same time, the row counter 53 for positioning the galvano mirror 16 for performing the scanning in the vertical direction is started. The value of is also updated.

  Therefore, in this embodiment, the value of the row counter 53 is not simply controlled to increase sequentially, but as shown in the laser scanning pattern examples of FIGS. 4A and 4B, two or more groups that do not scan the same place. The scanning pattern is controlled to be That is, control is performed so that the scanning by the scanning pattern of FIG. 4A and the scanning pattern of FIG.

  In FIG. 4A, horizontal scanning is performed at vertical scanning positions PAvi (i = 1, 2, 3... N−2, n−1, n) obtained by thinning every other vertical scanning position Pvi described above. Then, control is performed to perform horizontal scanning at the vertical scanning position PBvi (i = n + 1, n + 2, n + 3... 2n−2, 2n−1, 2n) obtained by thinning out the above-described vertical scanning position Pvi in FIG. 4A. As a result, the vertical scanning position PBvi (i = n + 1, n + 2, n + 3... 2n−2, 2n−1, 2n) in FIG. 4B corresponds to the vertical scanning position PAvi (i = 1, 2, 3... n-2, n-1, n) are shifted by one position.

Thus, when one cycle of scanning is completed by adding a large value (large interval) of the vertical scanning position PAvi in FIG. 4A, the position is slightly decremented from the top vertical scanning position in FIG. 4A as shown in FIG. 4B. The row addition for the next cycle is resumed. Note that the vertical scanning positions PAvi (i = 1, 2, 3... N−2, n−1, n) in FIG. 4A are i = 1, 3, 5,... Of the vertical scanning positions Pvi in FIG. 4B, the vertical scanning position PBvi (i = 1, 2, 3... N-2, n-1, n) in FIG. 4B corresponds to i = 2, 4, and 4 in the vertical scanning position Pvi in FIG. 3A. This corresponds to the even positions of 6,. As a result, when the scanning patterns of FIG. 4A and FIG. 4B are combined, Pvi is positioned at i = 1, n + 1, 2, n + 2, 3, n + 3... 2n as shown in FIG.
[III]. Image data processing control 2
Further, the fundus image (ophthalmologic image) is decomposed for each light reception wavelength by the third dichroic mirrors 33 and 34, and is received for each light reception wavelength by the first to third APDs 35 to 37 which are light receiving units. The image signals from the first to third APDs 35 to 37 are input to the ADCs 43 of the first to third image construction units 39 to 41, respectively, and A / D converted. Each of the first to third image constructing units 39 to 41 stores image dot data A / D converted by the ADC 43 for each frame, and reads out the image data stored in the image memory 44. An address generation unit 47 is included.

  For this reason, the first to third image construction units 39 to 41 divide into two scanning fields, that is, the field shown in FIG. 4A and the field shown in FIG. An image can be constructed by (field) 1 and scanning group (field) 2 in FIG. 4B to construct a high-speed frame rate moving image.

  When the images of the respective fields obtained by the scanning of scanning group 1 shown in FIG. 4A and scanning group 2 shown in FIG. 4B are combined, a scanning pattern for one frame as shown in FIG. 4C is obtained. Then, the fundus image (image) Er1 of FIG. 5 is constructed by the scan pattern of the scan group 1 shown in FIG. 4A, and the fundus image (image) Er2 of FIG. 5 is constructed by the scan of the scan group 2 shown in FIG. 4B.

  In the fundus oculi image Er1, for example, fundus bleeding portions 74a to 74d are imaged in addition to the features such as the nipple portion 70, the macula portion 71, and the fundus blood vessels 72 and 73. Further, in the fundus oculi image Er2, for example, fundus bleeding portions 75a to 75d are imaged in addition to the characteristic portions such as the nipple 70, the macula portion 71, and the fundus blood vessels 72 and 73. Then, by combining the fundus image (image) Er1 and the fundus image Er2 in FIG. 5, a combined fundus image Er3 is obtained. In the fundus oculi image Er3, an image including a fundus bleed portion 74a to 74d and a fundus bleed portion 75a to 75d in addition to features such as the nipple 70, the macula portion 71, and the fundus blood vessels 72 and 73 is constructed. In this embodiment, the scanning groups 1 and 2 are scanned at intervals at which the number of horizontal scanning lines is half the number of scanning lines of a normal scanning pattern.

In this image data processing control, the scanning patterns of the scanning group 1 in FIG. 4A and the scanning group 2 in FIG. 4B are used. However, the present invention is not necessarily limited to this. For example, as shown in FIG. 6, the fundus image may be constructed by scanning the fundus in the scan groups 1 to 3 divided into three fields. Scanning of the fundus with the spot illumination light is performed in the scanning group 1 at the vertical scanning position Pvi (i = 1, 2, 3... N) in FIG. 6, and the scanning group 2 is in the vertical scanning position Pvi in FIG. (I = n + 1, n + 2, n + 3... 2n), and scanning group 3 is performed at the vertical scanning position Pvi (i = 2n + 1, 2n + 2, 2n + 3... 3n) in FIG. In this case, a fundus image for one frame can be constructed by combining the fundus images of the respective fields obtained by scanning the fundus with the scan groups 1 to 3 by image processing. In this case, the scanning groups 1 to 3 are scanned at intervals at which the number of horizontal scanning lines is 1/3 of the number of scanning lines of a normal scanning pattern. In this way, scanning is performed in which the scanning line interval is 1 / X according to the number X of scanning groups.
[IV]. Actual processing control of image data 3
Next, as shown in FIG. 7, a case will be described in which the fundus Er is divided into four fields (scanning groups) for high-speed scanning, and the fundus Er is scanned at high speed in these four fields, that is, four scanning groups. .

In this embodiment, a tracking start switch Ts is provided as shown in FIG. 2, and an ON / OFF signal of the tracking start switch Ts is input to the control circuit 60. Then, when the tracking start switch Ts is turned on and this ON signal is input to the control circuit 60, the control circuit 60 starts tracking.
<Scanning group>
(A). Scanning pattern grouping for fast fundus scanning Here, when all normal fundus scanning lines are (1, n + 1,2n + 1,3n + 1,3... N, 2n, 3n, 4n) in FIG. , Horizontal scanning position in the vertical direction of all scanning lines for high-speed scanning,
Scan group 1
First vertical scanning position (1, 2, 3,... N)
Scan group 2
Second vertical scanning position (n + 1, n + 2, n + 3... 2n)
Scan group 3
Third vertical scanning position (2n + 1, 2n + 2, 2n + 3... 3n)
Scan group 4
Fourth vertical scanning position (3n + 1, 3n + 2, 3n + 3... 4n)
These four vertical scanning positions are divided into scanning groups (fields) to form a high-speed scanning pattern I scanning group.

  The four scanning groups 1 to 4 of the high-speed scanning pattern I are stored in advance in a memory (not shown) of the control circuit 60. In FIG. 8, the scans of the scan groups S0 to S4 are switched by the scan timings S0 to S4.

That is, the scanning timing is · S0
Normal scanning by all scanning lines (1, n + 1, 2n + 1, 3n + 1, 3... N, 2n, 3n, 4n) S1
High-speed scan by scan group 1 S2
High-speed scan by scan group 2 S3
High-speed scan by scan group 3 S4
High-speed scanning by the scanning group 4 is executed.

In the following description, S1 to S4 are nS1 to nS4 when the number of scans of the high-speed scanning group pattern I is n.
<Reference image BEr>
(B). Acquisition of the reference image BEr at the scanning timing S0 in FIG. 8 In such a setting, the tracking start switch Ts is turned on to start tracking, and photographing of the fundus is started. First, the fundus of the normal scanning pattern by all the scanning lines is started. An image (image) is acquired as a reference image.

That is, when the tracking start switch Ts is turned on, the control circuit 60 controls the operation of the mirror drive control circuit 42 of the image data processing circuit 38, and the mirror drive control circuit 42 controls the operation of the resonant mirror 13 and the galvano mirror 16. Then, the spot illumination light is projected onto the fundus of the eye E to be scanned in the normal scanning pattern by the resonant mirror 13 and the galvanometer mirror 16 of FIG. 1 at the scanning timing S0 of FIG. This scanning is performed using all the scanning lines (1, n + 1, 2n + 1, 3n + 1, 3,... N, 2n, 3n, 4n) in FIG. 7 as the fundus image (image) of the normal scanning pattern as the reference image BEr in FIG. 8A. The reference image BEr is acquired by the data processing circuit 38 and stored (stored) in the image memory 44 of the image data processing circuit 38.
<Fundus scan with high-speed scan group pattern I>
(C). Detection of deviation amount of fundus image acquired by high-speed scanning with respect to reference image BEr After acquiring the reference image BEr, the control circuit 60 controls the operation of the mirror drive control circuit 42 of the image data processing circuit 38, and the mirror drive control circuit 1 is changed (switched) from the normal scanning pattern to the high-speed scanning group pattern I shown in FIG.

  When the control circuit 60 controls to change the scanning pattern to the high-speed scanning group pattern I, the high-speed scanning group pattern I (first time), I (second time), the high-speed scanning group pattern I (third time) in FIG. Control is sequentially repeated as in the high-speed scanning group pattern I (n-th time).

  Here, the scanning groups 1 to 4 scan the fundus Er in FIG. 1 with spot illumination light (spot laser light) as described above. Then, the scanning group 1 is performed at the vertical scanning position Pvi (i = 1, 2, 3... N) in FIG. 7, and the scanning group 2 is performed in the vertical scanning position Pvi (i = n + 1, n + 2, n + 3,. .. 2n), the scanning group 3 is performed at the vertical scanning position Pvi (i = 2n + 1, 2n + 2, 2n + 3... 3n) in FIG. 7, and the scanning group 4 is performed at the vertical scanning position Pvi (i = 3n + 1, 3n + 2, 3n + 3... 4n).

As shown in FIG. 8, the scanning timings 1S1 to 1S4 by the scanning groups 1 to 4 of the high-speed scanning group pattern I (first time) and the scanning timings by the scanning groups 1 to 4 of the high-speed scanning group pattern I (second time). The fundus scanning at 2S1 to 2S4, the scanning timings 3S1, 3S2, etc. by the scanning groups 1 and 2 of the high-speed scanning group pattern I (third time) will be described.
(i) Fundus scanning with high-speed scanning group pattern I (first time)
(i-1). Scanning timing 1S1 (detection of fundus image Er1)
When the reference image BEr is acquired at the scanning timing S0, the control circuit 60 described above performs scanning of the fundus Er by the scanning group 1 at the scanning timing 1S1 of the high-speed scanning group pattern I (first time), and the fundus image Er1 ( Image).
(i-2). Scanning timing 1S2 (detection of fundus image Er2)
(Detection of fundus image Er2, detection of first shift amount Δx1 of first fundus image Er1 with respect to reference image BEr, and correction process for next scanning)
In addition, when the fundus image Er1 (image) is acquired, the control circuit 60 performs scanning of the fundus Er by the scan group 2 at the scan timing 1S2 of the high-speed scan group pattern I (first time), and the fundus image Er2 (image) ) To get.

  On the other hand, the personal computer 50 or the control circuit 60 extracts feature points of the fundus image Er1 (image) by image processing while acquiring the fundus image Er2 (image) by the scan group 2 at the scan timing 1S2. A first shift amount Δx1 (see FIG. 8A) between the image BEr and the fundus image Er1 obtained by the scanning group 1 is detected.

Then, the control circuit 60 performs scanning based on the detected first deviation amount Δx1 before scanning with the spot illumination light of the scanning group 3 of the high-speed scanning group pattern I (first time). Shift correction processing 1 is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror driving circuit 52 so that the detected first deviation amount Δx1 is canceled, and the pixel clock generation circuit 54 causes the pixel clock PcL to shift. The timing is shifted.
(i-3). Scanning timing 1S3 (detection of fundus image Er3)
(Detection of fundus image Er3, detection of second shift amount Δx2 of first fundus image Er2 with respect to reference image BEr, and correction process for next scanning)
Further, when the fundus oculi image Er2 (image) is acquired, the control circuit 60 performs scanning of the fundus oculi Er by the scanning group 3 at the scanning timing 1S3 of the high-speed scanning group pattern I (first time) based on the shift correction processing 1. Then, the fundus oculi image Er3 (image) is acquired.

  On the other hand, the personal computer 50 or the control circuit 60 extracts feature points of the fundus oculi image Er2 (image) by image processing while acquiring the fundus oculi image Er3 (image) by the scan group 3 at the scan timing 1S3. A second shift amount Δx2 (see FIG. 8B) between the image BEr and the fundus oculi image Er2 obtained by the scanning group 2 is detected.

The control circuit 60 performs scanning for scanning based on the detected second deviation amount Δx2 before scanning with the spot illumination light of the scanning group 4 of the high-speed scanning group pattern I (first time). Shift correction processing 2 is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror driving circuit 52 so as to correct the detected second shift amount Δx 2, and the pixel clock PcL is shifted by the pixel clock generation circuit 54. The timing is shifted.
(i-4). Scanning timing 1S4 (detection of fundus image Er4)
(Detection of fundus image Er4, detection of third deviation amount Δx3 of first fundus image Er3 with respect to reference image BEr, and correction process for next scanning)
Further, when the fundus oculi image Er3 (image) is acquired, the control circuit 60 performs scanning of the fundus oculi Er by the scanning group 4 at the scanning timing 1S4 of the high-speed scanning group pattern I (first time) based on the shift correction processing 2. Then, the fundus oculi image Er4 (image) is acquired.

  On the other hand, the personal computer 50 or the control circuit 60 extracts feature points of the fundus oculi image Er3 (image) by image processing while acquiring the fundus oculi image Er4 (image) by the scan group 4 at the scan timing 1S4. A third shift amount Δx3 between the image BEr and the fundus image Er3 obtained by the scanning group 3 is detected in the same manner as the shift amount Δx1.

Then, the control circuit 60 performs scanning for scanning based on the detected third shift amount Δx3 before scanning with the spot illumination light of the scanning group 1 of the high-speed scanning group pattern I (second time). Shift correction processing 3 is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror driving circuit 52 so that the detected third shift amount Δx3 is canceled, and the pixel clock PcL is shifted by the pixel clock generation circuit 54. The timing is shifted.
(ii). Fundus scanning by the high-speed scanning group pattern I (second time) When the first scanning by the high-speed scanning group pattern I is completed, the scanning timings 2S1 to 2S4 of the high-speed scanning group pattern I (second time) in FIG. Scans of scan groups 1 to 4 are executed.
(ii-1). Scanning timing 2S1 (detection of fundus oculi image Er1 ')
(Detection of fundus image Er1 ′, detection of fourth shift amount Δx4 of fundus image Er4 with respect to reference image BEr, and correction process for next scanning)
When the above-described control circuit 60 acquires the fundus image Er4 (image) by the scan group 4 at the scan timing 1S4 of the high-speed scan group pattern I (first time), the high-speed scan group pattern I (second time) is obtained based on the shift correction processing 3. ) Is scanned at the scanning timing 2S1, and the fundus Er is scanned by the scanning group 1 to obtain the fundus image Er1 ′ (image).

  On the other hand, the personal computer 50 or the control circuit 60 acquires the fundus image Er1 ′ (image) by the scanning group 1 at the scanning timing 2S1 of the high-speed scanning group pattern I (second time), while the high-speed scanning group pattern I (1 The feature points of the fundus image Er4 (image) obtained in the scanning group 4 of the first time are extracted by image processing, and the fundus image obtained by the scanning group 4 of the reference image BEr and the high-speed scanning group pattern I (first time). The fourth deviation amount Δx4 of Er4 is detected in the same manner as the deviation amount Δx1.

The control circuit 60 performs scanning for scanning based on the detected fourth shift amount Δx4 before scanning with the spot illumination light of the scanning group 2 of the high-speed scanning group pattern I (second time). Shift correction processing 4 is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror drive circuit 52 so that the detected fourth shift amount Δx4 is canceled, and the pixel clock generation circuit 54 causes the pixel clock PcL. The timing is shifted.
(ii-2). Scanning timing 2S2 (detection of fundus image Er2 ')
(Detection of fundus oculi image Er2 ', detection of first deviation amount Δx1' of fundus oculi image Er2 'for the second time with respect to reference image BEr, and correction processing for next scanning)
Further, when the fundus image Er1 ′ (image) is acquired, the control circuit 60 scans the fundus Er by the scan group 2 at the scan timing 2S2 of the high-speed scan group pattern I (second time) based on the shift correction process 4. The fundus image Er2 ′ (image) is acquired.

  On the other hand, the personal computer 50 or the control circuit 60 acquires the fundus image Er2 ′ (image) by the scanning group 2 at the scanning timing 2S2 of the high-speed scanning group pattern I (second time), while the high-speed scanning group pattern I (2 The feature points of the fundus image Er1 ′ (image) obtained by the scanning group 4 of the second time are extracted by image processing, and the first shift amount Δx1 between the reference image BEr and the fundus image Er1 ′ obtained by the scanning group 1 is extracted. ′ Is detected.

Then, the control circuit 60 performs scanning (scanning) with the spot illumination light of the scanning group 3 of the high-speed scanning group pattern I (second time) based on the detected first deviation amount Δx1 ′. A shift correction process 1 'for scanning is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror driving circuit 52 so that the detected first deviation amount Δx1 ′ is canceled, and the pixel clock generating circuit 54 The timing of PcL is shifted.
(ii-3). Scanning timing 2S3 (detection of fundus oculi image Er2 ')
(Detection of fundus oculi image Er2 ′, detection of second deviation amount Δx2 ′ of fundus oculi image Er2 ′ for the second time with respect to reference image BEr, and correction processing for next scanning)
Further, when the fundus oculi image Er2 ′ (image) is acquired, the control circuit 60 scans the fundus oculi Er by the scanning group 3 at the scanning timing 2S3 of the high-speed scanning group pattern I (second time) based on the shift correction processing 1 ′. To obtain the fundus oculi image Er3 ′ (image).

  On the other hand, the personal computer 50 or the control circuit 60 acquires the fundus image Er2 ′ (image) while acquiring the fundus image Er3 ′ (image) by the scanning group 3 at the scanning timing 2S3 of the high-speed scanning group pattern I (second time). Are extracted by image processing, and a second shift amount Δx2 ′ between the reference image BEr and the fundus oculi image Er2 ′ obtained by the scanning group 2 is detected.

Then, the control circuit 60 performs scanning (scanning) with the spot illumination light of the scanning group 4 of the high-speed scanning group pattern I (second time) based on the detected second deviation amount Δx2 ′. Shift correction processing 2 'for scanning is performed. That is, the scanning start position of the galvano mirror 16 is shifted via the galvano mirror driving circuit 52 so as to cancel the detected second deviation amount Δx 2 ′ for the second time, and the pixel clock generation circuit 54. To shift the timing of the pixel clock PcL.
(ii-4). Scanning timing 2S4 (detection of fundus oculi image Er4 ′)
(Detection of fundus oculi image Er4 ', detection of third deviation amount Δx3' of fundus oculi image Er3 'for the second time with respect to reference image BEr, and correction processing for next scanning)
When the fundus image Er3 ′ (image) is acquired, the control circuit 60 scans the fundus Er by the scan group 4 at the scan timing 2S4 of the high-speed scan group pattern I (second time) based on the shift correction processing 2 ′. To obtain the fundus oculi image Er4 ′ (image).

  On the other hand, the personal computer 50 or the control circuit 60 acquires the fundus image Er3 ′ (image) while acquiring the fundus image Er4 ′ (image) by the scan group 4 at the scan timing S4 of the high-speed scan group pattern I (second time). Are extracted by image processing, and the third displacement amount Δx3 ′ between the reference image BEr and the fundus image Er3 ′ obtained by the scanning group 3 is detected in the same manner as the displacement amount Δx1.

Then, the control circuit 60 performs scanning (scanning) with the spot illumination light of the scanning group 1 of the high-speed scanning group pattern I (third time) based on the detected third deviation amount Δx3 ′ for the second time. A shift correction process 3 'for scanning is performed. That is, the scanning start position of the galvanomirror 16 is shifted via the galvanomirror driving circuit 52 so as to correct the detected third misalignment amount Δx3 ′ of the second time, and the pixel clock generation circuit 54 is shifted. To shift the timing of the pixel clock PcL.
(iii). Fundus scanning by high-speed scanning group pattern I (third time) to (n-th) (detection of the fourth deviation amount Δx4 ′ of the second fundus image Er4 ′ with respect to the reference image BEr and correction processing of the next scanning)
When the above-described control circuit 60 acquires the fundus image Er4 ′ (image) by the scanning group 4 at the scanning timing 2S4 of the high-speed scanning group pattern I (second time), the high-speed scanning group pattern I ( The fundus Er is scanned by the scan group 1 at the (third) scan timing 3S1, and a fundus image Er1 ″ (image) is acquired.

  On the other hand, the personal computer 50 or the control circuit 60 acquires the fundus image Er1 ″ (image) by the scanning group 1 at the scanning timing 3S1 of the high-speed scanning group pattern I (third time). Feature points of the fundus image Er4 ′ (image) obtained in the first scanning group 4 are extracted by image processing, and obtained by the scanning group 4 of the reference image BEr and the high-speed scanning group pattern I (second time). The fourth shift amount Δx4 ′ of the fundus image Er4 is detected in the same manner as the shift amount Δx1.

  Then, the control circuit 60 performs scanning (scanning) with the spot illumination light of the scanning group 2 of the high-speed scanning group pattern I (third time) based on the detected fourth deviation amount Δx4 ′. A shift correction process 4 'for scanning is performed. That is, the scan start position of the galvano mirror 16 is shifted via the galvano mirror drive circuit 52 so that the detected fourth shift amount Δx4 ′ is canceled, and the pixel clock generation circuit 54 The timing of PcL is shifted.

  Further, scanning after the scanning timing 3S2 of the high-speed scanning group pattern I (third time) is also performed in the same manner as the scanning timing 3S1 of the high-speed scanning group pattern I (second time) scanning timing 2S1 to the high-speed scanning group pattern I (third time). The scans of the scan groups 1 to 4 are executed at the timing, and the shift amount of the acquired fundus image with respect to the reference image BEr is scanned from the scan timing 2S1 to the fast scan group pattern I (third) of the fast scan group pattern I (second). Detection is performed in the same manner as at timing 3S1, and shift correction processing of the shift amount for the next scanning is performed.

  As described above, in this embodiment, the fundus image (ophthalmologic image) obtained by the previous scanning group is converted into the reference image (reference fundus image by normal scanning due to fixation eye movement of the eye E before the start of scanning by the next scanning group. ) To detect the degree of deviation. For detection of this deviation, the nipple 70 of the fundus image (ophthalmologic image) obtained by the previous scanning group is used as a feature point. The amount of deviation is detected by the degree of deviation from the nipple portion 70).

As described above, the shift correction process 1 for scanning (scanning) is performed while the scanning group 2 of the high-speed scanning group pattern I (first time) is being scanned, and the shift correction process 2 is performed in the high-speed scanning group pattern I. The shift correction process 3 is performed while the scan group 4 of the high-speed scan group pattern I (first time) is performed, while the scan group 3 of the first scan is performed.
The shift correction process 4 is performed while the scanning group 1 of the high-speed scanning group pattern I (second time) is being scanned.

  Further, the shift correction processing 1 'for scanning (scanning) is performed while the scanning group 2 of the high-speed scanning group pattern I (second time) is being scanned, and the shift correction processing 2' is performed in the high-speed scanning group pattern. The shift correction process 3 ′ is performed while the scan of the scan group 4 of the high-speed scan group pattern I (second time) is performed. Then, the shift correction process 4 'is performed while the scan of the scan group 1 of the high-speed scan group pattern I (third time) is being performed.

  In the high-speed scanning group pattern I (first time), the scanning with the spot illumination light based on the shift correction process 1 is reflected in the scanning of the scanning group 3, and the scanning with the spot illumination light based on the shift correction process 2 is performed on the scanning group 4. Reflected in the scan. In the high-speed scanning group pattern I (second time), the scanning with the spot illumination light based on the shift correction process 3 is reflected in the scanning of the scanning group 1, and the scanning with the spot illumination light based on the shift correction process 4 is performed on the scanning group 4. Reflected in the scan. Similarly, in the high-speed scanning group pattern I (third time), the scanning by the spot illumination light based on the shift correction process 1 ′ is reflected in the scanning of the scanning group 1, and the scanning by the spot illumination light based on the shift correction process 2 ′ is performed by scanning. Reflected in group 2 scans.

  In the high-speed scanning group pattern I (first time), the images of the scanning groups 1 and 2 and the fields of the scanned scanning groups 3 and 4 are combined by image processing to construct one high-resolution image. Display on the monitor. In the high-speed scanning group pattern I (second time), the images of the fields of the scanned scanning groups 1 to 4 are synthesized by image processing, and one high-resolution image is constructed and displayed on the monitor. . Similarly, in the high-speed scanning group pattern I (n-th time), the images of the fields in the scanned scanning groups 1 to 4 are synthesized by image processing, and one high-resolution image is constructed and displayed on the monitor. To do.

  By such control and image processing, it is possible to obtain a moving image in which an image having a resolution that is the same as that of a normal scan image is tracked at a sampling frequency four times that of the normal scan.

  As described above, since it is possible to simultaneously obtain moving images having different frame rates from the scan groups 1 to 4 with respect to the normal scan image, the position correction of the image to be processed and the tracking accuracy of the shooting position are improved, and high quality diagnosis is performed. An image can be provided.

  The feature point for detecting the amount of deviation is the nipple 70, but the fundus blood vessels 72 and 73 other than the nipple 70, fundus bleeding portions 74a to 74d, 75a to 75d, and the like can be used. Multiple combinations are possible. The determination of the feature points can be easily set by the control circuit 60 if the amount of light in the fundus image has a certain area when the reference image is captured.

In the above-described embodiment, the fundus image captured first is used as the reference image, but is not necessarily limited thereto. For example, the reference image for detecting the shift amount of the image of the high-speed scanning group pattern I (n-th) is several times before the high-speed scanning group pattern I (n-th) (for example, one or two before). A fundus image constructed by photographing with the high-speed scanning group pattern I may be used.
(E). In the above example, the shift amount is detected and the shift correction processing is performed at the stage where the scanning of each field is completed. The amount of misalignment may be detected at the stage where scanning is completed. If the feature point for detecting the amount of deviation is the nipple 70, the amount of deviation can be ensured when capturing a fundus image in which the nipple 70 is positioned at the approximate center of the fundus image in the vertical direction. It can be detected.

  By doing so, the time for detecting the shift amount can be shortened, so that the shift correction processing and the feedback control by this can be accelerated.

  For example, scanning correction control by shift processing can be performed in the latter half of the time when the second fundus image is captured.

  In this embodiment, the feature point for detecting the deviation amount is the nipple 70, but the fundus blood vessels 72 and 73 other than the nipple 70, fundus bleeding portions 74a to 74d, 75a to 75d, and the like may be used. A plurality of these can be combined. The determination of the feature points can be easily set by the control circuit 60 if the amount of light in the fundus image has a certain area when the reference image is captured.

  In this case, if the feature point is the fundus blood vessel 72, the amount of deviation can be detected when the length of the fundus blood vessel 72 is detected to some extent, so that the time point is faster than when the amount of deviation is detected with the nipple 70 as the feature point. Thus, feedback control by shift correction processing can be performed.

  Note that when shooting high-resolution images with SLO, the frame rate of the moving image is low because the scanning pitch is set fine, and the moving image screen in this state is the upper and lower (or left and right) shooting images. Since the time difference becomes large, it becomes difficult to perform uniform focus and alignment adjustment on the entire image. However, the frequency of the frame rate of each scanning group can be increased by capturing fundus images with a plurality of scanning groups in which the number of scans is reduced and the scanning positions are shifted in addition to the basic image as in this embodiment. In addition, since the amount of deviation is detected from a captured image of another scan group with respect to the basic image, tracking based on this amount of deviation is performed, and a fundus image is captured with a scan group with a high frequency frame rate. The difference between the first half and the second half of the fundus image and the deviation of the fundus image in each scanning group can be reduced. Then, by combining a plurality of fundus images with little deviation and constructing a fundus image for one frame, it is possible to obtain a fundus image without deviation when photographing with a fine scanning pitch.

  As described above, the laser scanning type photographing apparatus according to the embodiment of the present invention includes the laser light generating means (illumination light generating section 3) for emitting laser light for photographing, and the scanning means for scanning the laser light ( An illumination optical system 1 that includes a resonant mirror 13 and a galvanometer mirror 16, and that scans and projects laser light onto a subject to be photographed (fundus) by the scanning means (resonant mirror 13 and galvanometer mirror 16); and the subject to be photographed The light receiving optical system 2 that receives the reflected laser light and guides it to the light receiving means (light receiving unit 30), and the light receiving means (every scanning period of the laser light by the scanning means (resonant mirror 13, galvanometer mirror 16)). An image constructing unit (first to third image constructing units 35 to 37) for constructing an observation image for one frame of the imaging target unit (fundus) from an output signal of the light receiving unit 30); It said scanning means (resonant mirror 13, the galvanometer mirror 16) and a control circuit for controlling operation of the scanning (image data processing circuit 38), the. In addition, the control circuit (image data processing circuit 38) is different for each scanning period of the laser light, and the scanning means (resonant mirror 13, galvanometer) with a plurality of scanning patterns that do not scan the same portion of the object to be imaged. By controlling the operation of the mirror 16), the image construction unit (first to third image construction units 39 to 41) uses the image construction unit (first to third image construction units 39 to 41) to generate a moving image of the object to be imaged (fundus) according to different scanning patterns of the laser light. By constructing a plurality of images and synthesizing the plurality of moving image images, one photographed image of the portion to be photographed is formed.

  According to this configuration, it is possible to easily adjust the focus and alignment, and to improve the tracking state of the moving image for shooting.

  In the laser scanning type photographing apparatus according to the embodiment of the present invention, the plurality of moving image images have different frame rates.

  According to this configuration, by capturing a plurality of moving image images (fundus images) having different frame rates, a shift amount between the plurality of moving image images is detected, and a scanning position for imaging based on the shift amount is corrected. Therefore, the shift of the fundus image in the first half and the latter half of each scan group and the shift of the fundus image in each scan group can be reduced. Then, by combining a plurality of fundus images with little deviation and constructing a fundus image for one frame, it is possible to obtain a fundus image without deviation when photographing with a fine scanning pitch.

  Further, in the laser scanning type photographing apparatus according to the embodiment of the present invention, the plurality of moving image images are constructed by signals having different wavelengths.

  In the laser scanning imaging apparatus according to the embodiment of the present invention, the light receiving means (light receiving unit 30) includes a plurality of light receiving elements (first to third APDs 35 to 37) capable of receiving different wavelengths.

  In the laser scanning type photographing apparatus according to the embodiment of the present invention, the laser light generation means (illumination light generation unit 3) can irradiate a plurality of laser lights having different wavelengths.

DESCRIPTION OF SYMBOLS 1 ... Illumination optical system 2 ... Light reception optical system 3 ... Illumination light generation part (laser light generation means)
13 ... Resonant mirror (resonant scanner, scanning means)
16 ... Galvano mirror (scanning means)
30. Light receiving part (light receiving means)
35 ... 1st APD (light receiving element)
36: Second APD (light receiving element)
37 ... Third APD (light receiving element)
38... Image data processing circuit (control circuit)
39 ... 1st image construction part 40 ... 2nd image construction part 41 ... 3rd image construction part

Claims (6)

Laser light generating means for emitting laser light for photographing;
An illumination optical system that includes a scanning unit that scans the laser beam, and that scans and projects the laser beam onto the object to be imaged by the scanning unit;
A light receiving optical system that receives reflected light and / or fluorescence from the object to be imaged and guides it to a light receiving means;
An image construction unit for constructing the observation image of the subject to be imaged object unit from the output signal of the light receiving means of said laser beam by said scanning means,
A control circuit for controlling the scanning of the scanning means;
Equipped with a,
Wherein the control circuit, by actuating controls the scanning means in a scanning pattern of a plurality of scan group that different for each scanning cycle of the laser beam in order for each of the scan group, the object according to different scanning patterns of said laser beam The moving image of the shooting target part is constructed in order by the image construction unit for each scanning group, and different moving picture images acquired by the plurality of scanning groups are combined to form one moving picture of the shooting target part. A laser scanning imaging device for forming an image for use ,
The control circuit controls the scanning unit to acquire an image of the object to be imaged as a reference image by scanning with a normal scanning pattern, and then converts the moving image of the object to be imaged into the plurality of different scanning patterns. When sequentially acquiring in the scanning group, the moving image image acquired in the scanning group before the scanning group being scanned while scanning the target object with one of the plurality of scanning groups, A laser scanning imaging apparatus , wherein a deviation amount from the reference image is detected, and correction processing of a scanning start position of a scanning group subsequent to the scanning group being scanned is executed based on the deviation amount . 2. The laser scanning imaging apparatus according to claim 1, wherein the control circuit obtains a shift amount between the moving image based on a feature point of the moving image . 2. The laser scanning imaging apparatus according to claim 1 , wherein the moving image having a different scanning pattern is different from a frame rate of the moving image formed by the synthesis . 2. The laser scanning imaging apparatus according to claim 1, wherein the moving image is constructed by signals having different wavelengths of one wavelength or two or more wavelengths . 2. The laser scanning imaging apparatus according to claim 1, wherein the light receiving means includes a plurality of light receiving elements capable of receiving different wavelengths. 2. The laser scanning type photographing apparatus according to claim 1, wherein the laser light generating means can irradiate a plurality of laser lights having different wavelengths.

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