Source: https://patents.google.com/patent/US7566132?oq=7%2C328%2C163
Timestamp: 2018-06-23 05:51:01
Document Index: 45579337

Matched Legal Cases: ['art 220', 'art 240', 'art 240', 'art 220', 'art 8', 'art 8', 'art 8', 'art 8', 'art 8', 'art 151', 'art 151', 'art 8', 'art 112', 'art 210', 'art 210', 'art 210', 'art 210', 'art 220', 'art 220', 'art 230', 'art 240', 'art 240', 'art 240', 'art 210', 'art 210', 'art 210', 'art 210', 'art 210', 'art 240', 'art 240', 'art 220', 'art 230', 'art 240', 'art 210', 'art 240', 'art 240', 'art 240', 'art 210', 'art 240', 'art 240', 'art 210', 'art 210', 'art 210', 'art 210', 'art 210', 'art 210', 'art 210', 'art 210', 'art 220', 'art 220', 'art 230', 'art 230', 'art 210', 'art 210', 'art 212', 'art 213', 'art 214', 'art 212', 'art 220', 'art 212', 'art 212', 'art 212', 'art 213', 'art 240', 'art 240', 'art 214', 'art 214', 'art 210', 'art 214', 'art 214', 'art 214', 'art 214', 'art 214', 'art 240', 'art 210', 'art 214', 'art 240', 'art 210', 'art 214', 'art 210', 'art 210', 'art 240', 'art 240', 'art 240', 'art 215', 'art 210', 'art 215', 'art 215', 'art 215', 'art 220', 'art 215', 'art 215', 'art 215', 'art 220', 'art 210', 'art.\n3', 'art.\n4']

US7566132B2 - Fundus observation device - Google Patents
US7566132B2
US7566132B2 US11697030 US69703007A US7566132B2 US 7566132 B2 US7566132 B2 US 7566132B2 US 11697030 US11697030 US 11697030 US 69703007 A US69703007 A US 69703007A US 7566132 B2 US7566132 B2 US 7566132B2
US11697030
US20070236660A1 (en )
LCD 140 is provided for displaying an internal fixation target for fixating an eye E. Projection optical system (a part of an imaging optical system 120) is provided for projecting the displayed internal fixation target onto the a fundus oculi Ef. Image forming part 220 is provided for forming 2-dimensional images (images of fundus oculi) Ef of the surface of fundus oculi Ef. Display part 240A is provided for displaying images of fundus oculi Ef. Operation part 240B is provided for specifying the position of the displayed images of fundus oculi Ef. Main controller 211 is provided for changing the projection position of the internal fixation target on the fundus oculi by changing the display position of the fixation target by the LCD 140 based on the specified position. The image forming part 220 forms tomographic images of the fundus oculi Ef with the internal fixation target projected.
As a fundus observation device, conventionally a fundus camera has been widely used. FIG. 11 shows one example of the appearance of a conventional fundus camera in general, and FIG. 12 shows one example of an optical system composition to be internally accommodated therein (e.g. JP Patent laid-open No. 2004-350849). Furthermore, “observation” is intended to include at least a case in which produced fundus images are observed (fundus observations with the naked eye may be included).
First, referring to FIG. 11, an explanation is made regarding the appearance of a conventional fundus camera 1000. This fundus camera 1000 is provided with a platform 3 mounted on a base 2 slidably in the front and rear, right and left (horizontal direction) directions. On this platform 3, an operation panel 3 a and a control lever 4 are installed for an examiner to conduct various operations.
On the side of the eye E of the main body part 8 (the left side of the page in FIG. 11), an objective lens part 8 a disposed opposite the eye E is installed. Also, on the examiner's side of the main body part 8 (the right side of the page in FIG. 11), an objective lens part 8 b for observing the fundus oculi of the eye E with the naked is installed.
Next, referring to FIG. 12, a composition of an optical system of the fundus camera 1000 is described. The fundus camera 1000 is provided with an illuminating optical system 100 to light the fundus oculi Ef of an eye E, an imaging optical system 120 to guide the fundus reflection light of the illumination light to the eyepiece part 8 b, a still camera 9, and an imaging device 10.
The Fourier domain OCT is designed to form a tomographic image having a depth-wise cross-section along its scanning line by scanning and irradiating a signal light onto the fundus oculi. Such scanning of signal lights is referred to as a B-scan (see NEDO Workshop “Seeing (examining) inside the body from the ‘window’ of the human body, the fundus oculi”—Development of an ultra early diagnostic device for lifestyle-related diseases using the latest optical technologies (held on Apr. 25, 2005).
When forming a 3-dimensional image, a B-scan is performed along a plurality of scanning lines, and an interpolation process is applied to the resulting plurality of tomographic images for the generation of 3-dimensional image data. This 3-dimensional image data is referred to as volume data, voxel data, and so forth, as well as medical imaging diagnosis devices such as an X-ray CT device, which is image data in a form in which pixel data (such as luminance value and RGB value regarding brightness, contrasting density and color) is assigned to each voxel. A 3-dimensional image is displayed as a pseudo 3-dimensional image seen from a certain viewing angle obtained by rendering volume data.
When scanning the peripheral region of a fundus oculi with signal light by an optical image measuring device, shading of signal light due to the iris of the eye or the like may occur and thereby the quality of the image may deteriorate, and at worst, an image may not be captured. Therefore, it is preferable to bring the region to be image-captured close to the optical axis of the optical system when capturing an image of the peripheral region of a fundus oculi, so as to avoid shading of signal light.
For that purpose, it is possible to project a fixation target onto the eye and to change the viewing angle of the eye so that the region to be image-captured is arranged close to the optical axis of the optical system. In this case, the relative position of the fundus oculi region to the scanning position of the signal light will be changed.
However, it is not easy to fixate the eye such that the desired position on the fundus oculi is arranged close to the optical axis of the optical system. Consequently, it is not easy to capture an image at the desired position on the fundus oculi.
The present invention is intended to solve the abovementioned problems, with the purpose of providing a fundus observation device capable of easily capturing an image at the desired position on a fundus oculi.
In order to achieve the above purpose, the first aspect of the present invention is constructed as follows; A fundus observation device comprising: fixation target projecting part including fixation target displaying part and a projection optical system, the fixation target displaying part being configured to display a fixation target for fixating an eye, the projection optical system being configured to project the displayed fixation target onto the a fundus oculi, projection position changing part configured to change the display position of said fixation target so as to change the projection position of the fixation target on the fundus oculi, and image forming part configured to form an image of the fundus oculi with said fixation target projected based on optically captured data, wherein s aid image forming part forms a 2-dimensional image of the surface of a fundus oculi based on optically captured data and further comprises displaying part configured to display the formed 2-dimensional image, and said projection position changing part includes operation part configured to specify a position on said displayed 2-dimensional image and changes the display position of said fixation target based on the position specified by said operation part.
FIG. 1 is a schematic diagram representing one example of the entire structure in a preferred embodiment of the fundus observation device related to the present invention.
FIG. 2 is a schematic diagram representing one structural example of a scanning unit installed in a fundus camera unit in a preferred embodiment of the fundus observation device related to the present invention.
FIG. 3 is a schematic diagram representing one structural example of an OCT unit in a preferred embodiment of the fundus observation device related to the present invention.
FIG. 5 is a schematic block diagram representing one structural example of a control system in a preferred embodiment of the fundus observation device related to the present invention.
FIG. 7 is a drawing showing a structural example of the arithmetic and control unit in an preferred embodiment related to the present invention.
FIG. 10 is a schematic block diagram representing one example of modification of preferred embodiment of the fundus observation device related to the present invention.
FIG. 11 is a schematic diagram showing one example of the appearance of a tomographic image of the fundus oculi acquired with a conventional fundus observation device (optical image measuring device).
FIG. 12 is a schematic diagram representing one example of an internal configuration (an optical system configuration) of a conventional fundus observation device (fundus camera).
One example of favorable embodiments of a fundus observation device related to the present invention is described in detail referring to figures. Furthermore, for structual parts that are the same as conventional ones, the same symbols used in FIG. 11 and FIG. 12 are used.
To the OCT unit 150, one end of a connection line 152 is attached. To the other end of this connection line 152, a connector part 151 is attached. This connector part 151 is attached to a mounting part 8 c shown in FIG. 11. Furthermore, a conductive optical fiber runs through the inside of the connection line 152. The OCT unit 150 and the fundus camera unit 1A are optically connected through the connection line 152. The constitution details of the OCT unit 150 are to be described later referring to FIG. 3.
A fundus camera unit 1A is a device for forming a 2-dimensional image of the surface of a fundus oculi of an eye based on optically captured data (data detected by imaging devices 10 and 12), and the fundus camera unit 1A has substantially the same appearance as the conventional fundus camera 1000 shown in FIG. 11. Furthermore, as in the conventional optical system shown in FIG. 12, the fundus camera unit 1A is provided with an illuminating optical system 100 to light a fundus oculi Ef of an eye E, and an imaging optical system 120 for guiding the fundus reflection light of the illumination light to an imaging device 10.
The observation light source 101 emits the illumination light of a wavelength in the visible region included within about 400 nm to 700 nm. Furthermore, the imaging light source 103 outputs the illumination light of a wavelength in the near-infrared region included within about 700 nm to 800 nm. The near-infrared light output from this imaging light source 103 is provided shorter than the wavelength of the light used by the OCT unit 150 (to be described later).
The imaging optical system 120 comprises: an objective lens 113, an aperture mirror 112 (aperture part 112 a thereof), an imaging diaphragm 121, a barrier filter 122 and 123, a variable magnifying lens 124, a relay lens 125, an imaging lens 126, a dichroic mirror 134, a field lens 128, a half mirror 135, a relay lens 131, a dichroic mirror 136, an imaging lens 133, an imaging device 10 (an image pick-up element 10 a), a reflection mirror 137, an imaging lens 138, an imaging device 12 (an image pick-up element 12 a), and a lens 139 and LCD (Liquid Crystal Display) 140.
The imaging optical system 120 related to the present embodiment is different from the conventional imaging optical system 120 shown in FIG. 12 in that the dichroic mirror 134, the half mirror 135, a dichroic mirror 136, the reflection mirror 137, the imaging lens 138, and the lens 139 and LCD 140 are provided.
In FIG. 2, one example of a concrete constitution of the scanning unit 141 is shown. The scanning unit 141 is comprised including Galvano mirrors 141A, 141B, and reflection mirrors 141C, 141D.
Next, the configuration of an OCT unit 150 is described with reference to FIG. 3.
The OCT unit 150 shown in the FIG. 3 is a device for forming a tomographic image of fundus oculi based on data captured by an optical scan (data detected by CCD 184 to be described below). The OCT unit 150 has a similar optical system to a conventional optical image measuring device. That is, the OCT unit 150 has an interferometer that splits the light emitted from a light source into a reference light and a signal light, and generates interference light by superposing the reference light having reached the reference object and the signal light having reached the object to be measured (fundus oculi Ef), and a device configured to output a signal as a result of detecting the interference light toward the arithmetic and control unit 200. The arithmetic and control unit 200 forms an image of the object to be measured (fundus oculi Ef) by analyzing this signal.
A low coherence light source 160 is composed of a broad band light source such as super luminescent diode (SLD) or a light emitting diode (LED), etc that emits low coherence light L0. This low coherence light L0, for instance, has a wave length in the near-infrared region and is supposed to be light having a time wise coherence length of approximately several tens of micro-meters. The low coherence light LO emitted from the low coherence light source 160 has a longer wavelength than the illumination light (wavelength: about 400 nm to 800 nm) of the fundus camera unit 1A, for example, a wavelength included within about 800 nm to 900 nm.
Furthermore, the glass block 172 and the density filter 173 act as a delaying a device for matching the optical path length (optical distance) between the reference light LR and the signal light LS, and as a device for matching the dispersion characteristics of reference light LR and the signal light LS.
Furthermore, although a Michelson type interferometer has been adopted in the present embodiment, for instance, a Mach Zender type, etc. or any optional type of interferometer may be adopted appropriately.
The spectrometer 180 is comprised of a collimator lens 181, a diffraction grating 182, an image forming lens 183, and a CCD (Charge Coupled Device) 184. The diffraction grating 182 in the present embodiment is a transmission type diffraction grating; however, needless to say, a reflection type diffraction grating may also be used. Furthermore, needless to say, in place of CCD 184, it is also possible to adopt other photo-detecting elements.
As for the control of the fundus camera unit IA, to be controlled is, for example: the emission of illumination light by the observation light source 101 or the imaging light source 103; the insertion/retraction operation of the exciter filters 105, 106, or the barrier filters 122, 123 on the optical path; the display operation of the LCD 140; the shift of the illumination diaphragm 110 (controlling the diaphragm value); the diaphragm value of the imaging diaphragm 121; the shift of the variable magnifying lens 124 (controlling the magnification), etc.
Furthermore, the display 207 may be any display device such as LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube), etc. which is configured to display images of a fundus oculi Ef formed by the fundus observation device 1 and also configured to display various operation screens or set up screens, etc. This display 207 (and /or a touch panel monitor 11) corresponds to one example of “display part” of the present invention.
An image forming board 208 is a dedicated electronic circuit for operating to form (image data of) the image of the fundus oculi Ef of an eye E. In this image forming board 208, the fundus image forming board 208 a and OCT image forming board 208 b are installed. The fundus image forming board 208 a is a dedicated electronic circuit for operating in order to form the image of the fundus oculi Ef′ based on the video signal from the imaging device 10 or the imaging device 12 of the fundus camera unit 1A. Furthermore, the OCT image forming board 208 b is a dedicated electronic circuit for operating in order to form image data of tomographic images of fundus oculi Ef′ based on the detecting signal from CCD 184 of the spectrometer 180 in the OCT unit 150. The image forming board 208 allows the processing speed for forming image data of fundus images Ef and tomographic images to improve.
The controlling part 210 executes said controlling processes by the microprocessor 201 that is operated based on the control program 204 a. In particular, the controlling part 210 executes control for allowing the LCD 140 to display an internal fixation target and control of the mirror drive mechanism 241, 242 of the fundus camera unit 1A to independently work the Galvano mirrors 141A, 141B as well as control of the reference mirror drive mechanism 243 to move the reference mirror 174 toward the direction in which the reference light LR travels.
Furthermore, the controlling part 210 executes control for allowing the display 207 of the user interface 240 to display two kinds of images produced by the fundus observation device 1: that is, a 2-dimensional image (fundus image Ef′) of the surface of a fundus oculi Ef by the fundus camera unit 1A, and an tomographic image(sectional image, 3-dimensional image, etc.) of a fundus oculi Ef formed based on the detection signal obtained by the OCT unit 150. These images can be displayed on the display 207 both respectively and simultaneously. As to the details of constitution of the controlling part 210, it is described later according to FIG. 7.
An image forming part 220 is intended to operate the process forming the fundus image based on the video signal from the imaging device 10 and 12 of the fundus camera unit 1A and to operate the process forming image data of the tomographic images of fundus oculi Ef based on the detecting signal from CCD 184 in the OCT unit 150. This image forming part 220 comprises an imaging forming board 208. In addition, “image” may be identified with corresponding “image data” relating to the present invention.
Herein, 3-dimensional data is image data made by assigning voxel values to each of a plurality of voxels arranged 3-dimensionally, referred to as volume data, voxel data, and so forth. When displaying an image based on volume data, the image processing part 230 operates to form image data of a pseudo 3-dimensional image seen from a particular viewing direction by applying a rendering process (such as volume rendering and MIP (Maximum Intensity Projection)) to this volume data. A display device such as a display device 207 will display such a pseudo 3-dimensional image based on the image data.
The user interface (UI) 240, as shown in FIG. 7, comprises a display part 240A consisting of a display device such as a display 207, and an operation part 240B consisting of an operation device and an input device such as a keyboard 205 and mouse 206. The operation part 240B corresponds to one example of “operation part” relating to the present invention.
The operation panel 3 a of the fundus camera unit 1A is described below. This operation panel 3 a is, as shown for example in FIG. 11, arranged on the platform 3 of the fundus camera unit 1A. The operation panel 3 a in the present embodiment is different from the conventional configuration described above, which is provided with an operation part used to input an operation request for capturing a 2-dimensional image of the surface of the fundus oculi Ef and an operation part used for the input operation of capturing a tomographic image of the fundus oculi Ef (traditionally, only the former operation part). Consequently, the OCT can also be operated in the same manner as operation of a traditional fundus camera.
The operation panel 3 a in the present embodiment is, as shown in FIG. 6, provided with a menu switch 301, a split switch 302, an imaging light amount switch 303, an observation light amount switch 304, a jaw holder switch 305, a photographing switch 306, a zoom switch 307, an image switch 308, a fixation target switch 309, a fixation target position adjusting switch 310, a fixation target size switch 311 and a mode switching knob 312.
The imaging light amount switch 303 is a switch operated to adjust the emission light amount of the imaging light source 103 (photographing light amount) depending on the state of the eye E to be examined (such as the degree of opacity of the lens). This imaging light amount switch 303 is provided with, for example, a photographing light amount increasing switch “+” for increasing the photographing light amount, a photographing light amount decreasing switch “−”, and reset switch (button in the middle) for setting the photographing ling amount to a certain initial value (default value). When one of the imaging light amount switches 303 is operated, the operation signal will be input to the controlling part 210. The controlling part 210 adjust the photographing light amount by controlling the imaging light source 103 depending on the operation signal that was input.
The observation light amount switch 304 is a switch operated to adjust the emission light amount (observation light amount) of the observation light source 101. The observation light amount switch 304 is provided with, for example, an observation light amount increasing switch “+” for increasing the observation light amount and an observation light amount decreasing switch “−” for decreasing the observation light amount. When one of the observation light amount switches 304 is operated, the operation signal will be input to the controlling part 210. The controlling part 210 adjusts the observation light amount by controlling the observation light source 101 depending on the operation signal that was input.
On the other hand, when the photographing switch 306 is operated while a menu is selected to capture a tomographic image, the controlling part 210 that has received the operation signal will control the low coherence light source 160, galvanometer mirrors 141A and 141B, and display part 240A or the touch panel monitor 11. The low coherence light source 160 is controlled to emit the low coherence light LO. The galvanometer mirrors 141A and 141B are controlled to scan the signal light LS. The display part 240A or the touch panel monitor 11 is controlled to display a tomographic image of the fundus oculi Ef formed by the image forming part 220 (and image processing part 230), based on the detecting signal output from the CCD 184 that has detected the interference light LC.
The image switch 308 is a switch for operation of switching displayed images. When the image switch 308 is operated during a fundus oculi observation image (a 2-dimensional image of the surface of the fundus oculi Ef based on the video signal from the imaging device 12) is displayed on the display part 240A or the touch panel monitor 11, the controlling part 210 that has received the operation signal will control the display part 240A or the touch panel monitor 11. The display part 240A or the touch panel monitor 11 displays the tomographic image of the fundus oculi Ef. On the other hand, when the image switch 308 is operated during the display of a tomographic image of the fundus oculi on the display part 240A or the touch panel monitor 11, the controlling part 210 that has received the operation signal will control the display part 240A or the touch panel monitor 11. The display part 240A or the touch panel monitor 11 is controlled to display the fundus oculi observation image.
The fixation target switch 309 is a switch for operation of switching the display position of the internal fixation target via the LCD 140 (i.e. the projection position of the internal fixation target in the fundus oculi Ef). When this fixation target switch 309 is operated, the controlling part 210 controls the LCD 140 so as to circulate switching the display position of the internal fixation target, for example, among “fixation position to capture the image including the center region of the fundus oculi (equivalent to the fist projection position of the internal fixation target)”. “fixation position to capture the image including macula area (equivalent to the second projection position)”, and “fixation position to capture the image including optic papilla (equivalent to the third projection position)”. That is, every time the internal fixation target switch 309 is operated, the projection position of the internal fixation target on the fundus oculi Ef is circulated from the first projection position ->the second projection position ->the third projection position ->the first projection position . . . .
The display positions of the internal fixation target corresponding with the above three fixation positions (projection positions), for example, may be preset based on clinical data, or may be set for that eye E (image of the fundus oculi Ef) in advance (that is, the display position may have been stored as examination information for each patient.). This fixation target switch 309 is equivalent to one example of the “operation part” of the present invention.
The fixation target position adjusting switch 310 is a switch operated to adjust the display position of the internal fixation target. This fixation target position adjusting switch 310 is provided with, for example, an upward movement switch for moving the display position of the internal fixation target upward, an downward movement switch for moving it downward, a leftward movement switch for moving it leftward, a rightward movement switch for moving it rightward, and a reset switch for moving it to a certain initial position (default position). The controlling part 210, when having received the operation signal from either of these switches, will control the LCD 140.The LCD 140 is controlled to move the display position of the internal fixation target. This fixation target position adjusting switch 310 corresponds to one example of the “operation part” of the present invention.
The fixation target size switch 311 is a switch for operation of changing the size of the internal fixation target. When this fixation target size switch 311 is operated, the controlling part 210 that has received the operation signal will control the LCD 140. The LCD 140 is controlled to changes the display size of the internal fixation target. The display size of the internal fixation target can be changed, for example, between “normal size” and “enlarged size,” alternately. As a result, the size of the projection image of the fixation target projected onto the fundus oculi Ef is changed.
FIG. 8 represents one example of scanning features of signal light LS for forming images of a fundus oculi Ef. FIG. 8A represents one example of scanning features of the signal light LS, when the signal light LS sees the fundus oculi Ef from an incident direction onto the eye E (that is, +direction of z is seen from −direction of z in FIG. 1). Furthermore, FIG. 8B represents one example of arrangement features of scanning points (positions at which image measurement is carried out) on each scanning line on the fundus oculi Ef.
In order to execute the scanning shown in FIG. 8, the controlling part 210 controls the Galvano mirrors 141A and 141B to set the incident target of the signal light LS with respect to a fundus oculi Ef at a scan start position RS(scanning point R11) on the first scanning line R1. Subsequently, the controlling part 210 controls the low coherence light source 160 to flush the low coherence light L0 for emitting the signal light LS to the scan start position RS. The CCD 184 receives the interference light LC based on the fundus reflection light of this signal light LS at the scan start position RS, and outputs the detection signal to the controlling part 210.
Once the measurement at the last scanning point R1n of the first scanning line R1 is finished, the controlling part 210 controls the Galvano mirrors 141A and 141B simultaneously and shifts the incident target of the signal light LS to the first scanning point R21 of the second scanning line R2 following a line switching scan r. Then, by conducting the previously described measurement with regard to each scanning point R2j (j=1 through n) of this second scanning line R2, a detection signal corresponding to each scanning point R2j is obtained.
As a result, the controlling part 210 obtains m ×n number of detection signals corresponding to m ×n number of scanning points Rij (i=1 through m, j=1 through n) within the scanning region R. Hereinafter, a detection signal corresponding to the scanning point Rij may be represented as Dij.
FIG. 9 represents a feature of (a group of) tomographic images formed by the image forming part 220. In the second step of the arithmetic process, with regard to each scanning line Ri, based on the images in the depth-wise direction at the n number of scanning points Ri1 through Rin thereon, a tomographic image Gi of a fundus oculi Ef along this scanning line Ri is formed. Then, the image forming part 220 determines the arrangement and the distance of each scanning point Ri1 through Rin while referring to the positional information (said scan positional information) of each scanning point Ri1 through Rin, and forms a tomographic image Gi along this scanning line Ri. Due to the above process, m number of tomographic images (a group of tomographic images) G1 through Gm at different positions of the sub-scanning direction (y-direction) are obtained.
Furthermore, based on this 3-dimensional image, the image processing part 230 is capable of forming a tomographic image of the fundus oculi Ef at a cross-section in an arbitrary direction other than the main scanning direction (x-direction).
Once the cross-section is designated, the image processing part 230 determines the position of each scanning point (and/or an image in the depth-wise direction that has been interpolated) on this designated cross-section, and extracts an image (and/or image in the depth-wise direction that has been interpolated) in the depth-wise direction at each determined position to form a tomographic image of the fundus oculi Ef at the designated cross-section by arranging plural extracted images in the depth-wise direction.
Detailed configuration of the arithmetic and control unit 200 is described with reference to FIG. 7. Herein, configuration of the controlling part 210 of the arithmetic and control unit 200 is specifically described.
The controlling part 210 is provided with a main controller 211, an image storage part 212, an information storage part 213, and a fixation position calculation part 214.
The main controller 211 comprises a microprocessor 201 or the like and controls each part of the fundus observation device 1 (previously described).
The image storage part 212 stores image data of a 2-dimensional image of the surface of the fundus oculi Ef (fundus oculi image) and image data of a tomographic image formed by the image forming part 220. A memory processing of image data to the image storage part 212 and a read processing of image data from the image storage part 212 are performed by the main controller 211. The image storage part 212 is constituted to include a memory device such as a hard disk drive 204.
The information storage part 213 includes a memory device such as a hard disk drive 204 storing the fixation position information 213 a in advance. Hereinafter, various information included in the fixation position information 213 a is explained in detail.
A 2-dimensional X-Y coordinate system is predefined on the display surface of LCD 140 (not shown). This X-Y coordinate system defines a plane parallel to a plane spanned by x coordinates and y coordinates of the x-y-z coordinate system shown in FIG. 1. Herein, scales (lengths of the unit distance) of the two coordinate systems may be either equal or different. In addition, the directions of the coordinate axes of the two coordinate systems may either coincide with each other or not.
Generally, in the case where the scales and the directions of the coordinate axes of the two coordinate systems are both different, the direction of the coordinate axes can be coincident with each other by parallel transfer and rotational transfer, and the scales can be coincident with each other by enlarging/contracting the length of the unit distance of the coordinate axes (in other words, an unique coordinate transformation can be performed.). The fixation position information 213 a includes a coordinate conversion equation between the coordinates of the x-y coordinate systems and the coordinates of X-Y coordinate systems.
In addition, the fixation position information 213 a includes coordinate values on the X-Y coordinate system indicating the display positions on the LCD 140, for each of the above three fixation positions, that is, the fixation position to capture the image of the peripheral region of the center of the fundus oculi (fixation position for the center of the fundus oculi), the fixation position to capture the image of the peripheral region of macula area (fixation position for macula area), and the fixation position to capture the image of the peripheral region of optic papilla ( fixation position for optic papilla). The coordinate values on the X-Y coordinate system are used for projecting the internal fixation target onto those fixation position.
In addition, the fixation position information 213 aincludes information indicating the correspondent relationship between the display position of the internal fixation target on the LCD 140 (coordinates on the display surface of the LCD 140) and the center position of the fundus oculi of the image, the image being captured when the eye E is fixated on this internal fixation target (image center point). When the display position of the internal fixation target is changed, the projection position of the internal fixation position on the fundus oculi Ef will be changed accordingly. When the eye E is fixated on this internal fixation target, the position of the fundus oculi Ef through which the optical axis of the optical system of the fundus camera unit 1A passes will be changed. As a result, the center point of the image provided by the imaging devices 10 and 12 or the OCT unit 150 will be changed. In this way, the information is used to change the display position so as to correspond with the center point of the image of the associated internal fixation target. Incidentally, this information may be set for each patient based on information such as the axial length of the eyeball, the center of convolution of the eye E, and so on, or may be set as general information based on clinical data and so on.
Fixation Position Information Calculation Part
The fixation target position adjusting switch 310 and the operation part 240B are operated to specify the desired position on the fundus oculi image Ef′ displayed on the touch panel monitor 11 or the display part 240A. The fixation position information calculation part 214 performs the process of calculating the position of the internal fixation target projected onto the fundus oculi Ef, that is, the display position of the internal fixation target on the LCD 140. This process of calculating is based on the position specified on the fundus oculi image Ef′ by the fixation target position adjusting switch 310 or the like.
To project the internal fixation target based on this specified position, for example, the following two operations can be applied: (1) projecting the internal fixation target onto the position on the fundus oculi Ef corresponding to the specified position; (2) projecting the internal fixation target onto the position on the fundus oculi Ef such that the image in which the position of fundus oculi Ef corresponding to the specified position is almost centered is captured.
For the case (1) above, the processing of the fixation position information calculation part 214 is specifically described. When the position on the fundus oculi Ef′ is specified, the coordinates of this specified position in the abovementioned x-y coordinate systems will be input from the user interface 240 to the controlling part 210, and will be sent to the fixation position information calculation part 214. The fixation position information calculation part 214 calculates the coordinates of the X-Y coordinate systems corresponding to the coordinates of this specified position. This calculation processing is performed using the coordinate conversion equation (described above) between the coordinates of the x-y coordinate system and the coordinates of X-Y coordinate systems included in the fixation position information 213 a. The X-Y coordinate obtained by the coordinate conversion are employed as the display position of the internal fixation target by the LCD 140 for projecting the internal fixation target onto the position on the fundus oculi Ef equivalent to that specified position. Incidentally, in the case where the position is specified on the fundus oculi Ef′ by the fixation target position adjusting switch 310 of the operation panel 3 a, similar processing will also be performed.
Next, the processing of the fixation position information calculation part 214 in the case of (2) above is specifically described. The fixation position information calculation part 214, in response to the position specified on the fundus oculi image Ef′, determines the display position of the internal fixation target on the LCD 140 with reference to the fixation position information 213 a so that the specified position is positioned at the center point of the image.
Incidentally, when the projection position of the internal fixation target and the center point of the image almost coincide with each other due to the structure of the optical system of the fundus camera unit 1A or the alignment of the optical system of the fundus camera unit 1A to the eye E, there is no need to distinguish between the processing in the case of (1) above and the processing in the case of (2) above. Therefore, at this time, the fixation position information calculation part 214 can be configured to perform only the processing in either (1) or (2) above.
Example Models of Use
Examples of use of the fundus observation device 1 having the above configuration are described. This fundus observation device 1 is different from the traditional configuration shown in FIG. 11 and FIG. 12, and is provided with the configuration in the optical system in the package of the fundus camera unit 1A, being configured to project the (internal) fixation target onto the fundus oculi Ef. Hereinafter, examples of usage patterns of this internal fixation target are described.
First Model of Use
First, a model of use for switching the position of the internal fixation target projected to the fundus oculi Ef is described. In this fundus observation device 1, the projection position of the internal fixation target can be switched to the fixation position for the center of the fundus oculi, the fixation position for macula area, and the fixation position for optic papilla. In this embodiment, the projection position of the internal fixation target is designed to circulate in the order of the following: the fixation position for the center of the fundus oculi ->the fixation position for macula area ->the fixation position for optic papilla.
When the fixation target switch 309 of the operation panel 3 a is operated (pressed), the operation signal will be input from the operation panel 3 a to the arithmetic and control unit 200.
The main controller 211, in response to the receipt of this operation signal, controls the display position of the internal fixation target by the LCD 140 so that the internal fixation target is projected onto a projection position next to the current projection position with reference to the fixation position information 213 a.
For example, when the fixation target switch 309 is operated with the internal fixation target projected onto the fixation position for optic papilla, the main controller 211 will switch the display position of the internal fixation target displayed on the LCD 140 so that the internal fixation target is projected onto the next fixation position for the center of the fundus oculi.
Incidentally, when the fixation target switch 309 is operated without the internal fixation target displayed on the LCD 140, the main controller 211 is designed to control the LCD 140 to display the internal fixation target at the display position where the internal fixation target is projected, for example, onto the fixation position for the center of the fundus oculi.
Second Model of Use
Next, a model of use for projecting the internal fixation target onto the position specified on the fundus oculi image Ef′ is described. When the position is specified on the fundus oculi image Ef′ by the mouse of the operation part 240B or the fixation target position adjusting switch 310 of the operation panel 3 a, the operation signal indicating the coordinates (x-y coordinates) of this specified position will be input to the controlling part 210.
The fixation position information calculation part 214 calculates the coordinates on the screen of the LCD 140 (X-Y coordinates). The coordinates correspond to the coordinates of the specified position indicated in this operation signal. The main controller 211 controls the LCD 140 to display the internal fixation target at the position of this calculated X-Y coordinates. As a result, the internal fixation target will be projected onto the position on the fundus oculi region Ef corresponding to that specified position.
Third Model of Use
Next, a model of use for is projecting the internal fixation target such that the position specified on the fundus oculi image Ef′ is the center point of the image is described. When the position is specified on the fundus oculi image Ef′ by the mouse of the operation part 240B or the fixation target position adjusting switch 310 of the operation panel 3a. the operation signal indicating the coordinates (x-y coordinates) of this specified position will be input to the controlling part 210.
The fixation position information calculation part 214 calculates the coordinates on the screen of the LCD 140 (X-Y coordinates) with reference to the fixation position information 213 a so that this specified position is the image center point. The main controller 211 controls the LCD 140 to project the internal fixation target onto the position of this calculated X-Y coordinates. As a result, the image of the fundus oculi Ef can be captured so that specified position is the image center point (a 2-dimensional image of the surface of the fundus oculi or a tomographic image) with the eye E fixated by this internal fixation target.
The effect and advantage of the fundus observation device 1 as above are as follows.
The fundus observation device 1 related to the present embodiment comprises a LCD 140 for displaying an internal fixation target, a projection optical system (a part of the imaging optical system 120 for forming an optical path of the light emitted from the LCD 140) for projecting the displayed internal fixation target onto the fundus oculi Ef, a controlling part 210 for changing the projection position of the internal fixation target on the fundus oculi Ef by changing the display position of the internal fixation position by the LCD 140, and so on. As a result, a 2-dimensional image of the surface of the fundus oculi or a tomographic image is formed by irradiating the photographing illumination light or signal light LS to the fundus oculi Ef with this internal fixation target projected.
According to such fundus observation device 1, the direction of fixation of the eye E can be easily changed compared to the traditional configuration in which the fixation has been conducted by an external fixation lamp. Therefore, it is possible to easily fixate the eye E in the desired direction, thereby enabling to easily capture any image at the desired position of the fundus oculi Ef.
Incidentally, the LCD 140 is equivalent to one example of the “fixation target displaying part” relating the present invention. In addition, the LCD 140 and the above projection optical system are equivalent of one example of the “fixation target projecting part” relating to the present invention. Furthermore, the controlling part 210 is included in one example of the “projection position changing part” relating to the present invention.
In addition, according to this fundus observation device 1, the internal fixation target can be projected onto the fixation position for the center of the fundus oculi, the fixation position for macula area, and fixation position for optic papilla on the fundus oculi Ef only by operating the fixation target switch 309. As a result, it is possible to easily capture images of the representative observation regions when observing the fundus oculi Ef. The representative observation regions may be images of the center of the fundus oculi, macula area and optic papilla.
Furthermore, the projection position of the internal fixation target can be switched among these three fixation positions only by operating the fixation target switch 309. As a result, it is possible to easily switch the direction of fixation of the eye E.
In addition, this fundus observation device 1, in response to the desired position on the fundus oculi Ef′ displayed on the display part 240A or the touch panel monitor 11 having been specified, operates to project the internal fixation target onto the position of the fundus oculi Ef equivalent to the specified position. As a result, it is possible to easily fixate the eye E in the desired direction.
In addition, this fundus observation device 1, in response to the desired position on the fundus oculi Ef′ displayed on the display part 240A or the touch panel monitor 11 having been specified, operates to project the internal fixation target onto the position on the fundus oculi Ef for capturing images of the fundus oculi in which the specified position is the center (a surface image or a tomographic image). As a result, it is possible to easily capture an image in which the desired position of the fundus oculi Ef is the center.
Incidentally, the display part 240A and the touch panel monitor 11 are equivalent of one example of the “displaying part” relating to the present invention, respectively. In addition, as shown in FIG. 1, in the direction perpendicular to the x-y plane (X-Y plane), z coordinate (Z coordinate; not shown) whose positive direction is the depth direction of the fundus oculi Ef is defined. Also, for z coordinate and Z coordinate, their scales may be either equal or different. Hereinafter, X-Y-Z coordinate system and x-y-z coordinate system shall be coincident with each other in the directions of each corresponding coordinate axis and the scale of each coordinate axis shall be equal.
Although the above fundus observation device 1 is configured so as to be capable of projecting the internal fixation target onto the fixation position for the center of the fundus oculi, the fixation position for macula area, and the fixation position for optic papilla on the fundus oculi Ef, it is sufficient to configure the fundus observation device related to the present invention to be capable of projecting the internal fixation target onto at least one of these fixation positions.
In addition, in the switching operation of the projection position of the internal fixation target, it is sufficient to be capable of switching the projection position of the internal fixation target to two fixation positions of these.
Incidentally, choices for the projection position of the internal fixation target are not limited to these three fixation positions, but it is possible to employ any position on the fundus oculi Ef as a choice.
In addition, while the LCD 140 is used as a fixation target displaying part for displaying a fixation target in the above embodiment, the fundus observation device related to the present invention is not limited to this. For example, any display device such as a plasma display, an organic EL (Electroluminescence) display, and a surface-conduction electron-emitter display can be used other than the LCD (Liquid Crystal Display). In addition, fixation target displaying part in which plurality of LEDs (Light Emitting Diodes) are 2-dimensionally (e.g., like a 2-dimensional array) arranged also can be applied. In that case, the projection position of the fixation target onto the fundus oculi is changed by selectively illuminating the plurality of LEDs.
The block diagram shown in FIG. 10 illustrates the configuration of a transformation example of the fundus observation device. This fundus observation device comprises a macula extracting part 215 in the controlling part 210 of the arithmetic and control unit 200. This macula extracting part 215 performs the processing for analyzing a tomographic image of a fundus oculi Ef and extracting an image region equivalent to the macula area of the fundus oculi Ef. This macula extracting part 215 acts as an example of the “extracting part”relating to the present invention.
The processing performed by the macula extracting part 215 is more specifically described. First, the image forming part 220 forms (image data of) a tomographic image of a fundus oculi Ef based on the detecting signal from the CCD 184. The macula extracting part 215 determines whether a concave portion equivalent to the macula area exists in the tomographic image by analyzing, for example, a pixel value (luminance value) of this tomographic image.
When a concave portion exists in the tomographic image, the macula extracting part 215 determines the coordinates (x-y coordinates) of the central position of the concave portion (the deepest part of the concave portion) in that tomographic image. The main controller 211 controls the LCD 140 so as to arrange the deepest part of the concave portion at the center of the image by changing the projection position of the internal fixation position onto the fundus oculi Ef. Incidentally, it may be designed to adjust the scanning region of the signal light LS by the Galvano mirrors 141A and 141B so that the deepest part of this concave portion is the center of the image.
When a concave portion does not exist in the tomographic image, the main controller 211 controls the LCD 140 to capture a new tomographic image by changing the projection position of the internal fixation target onto the fundus oculi Ef. The macula extracting part 215 determines whether a concave portion equivalent to the macula area exists in that tomographic image by analyzing this new tomographic image. When one exists, the projection position of the internal fixation target (or the scanning region of the signal light LS) will be changed so that the deepest part of the concave portion is arranged at the center of the image in the same manner as the above case. On the other hand, when no concave portion exists, the main controller 211 captures a new tomographic image by changing the projection position of the internal fixation target again. This processing will be repeated until a concave portion is extracted.
Moreover, in the above embodiment, the forming process of the images by the image forming part 220 (image forming board 208) and each controlling process are operated by the controlling part 210 (microprocessor 201, etc.), but it can be composed to operate these two processes by one or several computers.
fixation target projecting part configured to display a fixation target for fixating an eye and configured to project the displayed fixation target onto a fundus oculi,
projection position changing part configured to change the display position of said fixation target so as to change the projection position of the fixation target on the fundus oculi,
first image forming part operable to form a 2-dimensional image of the surface of a fundus oculi with said fixation target projected based on optically captured data;
second image forming part operable to form a tomographic image of a fundus oculi based on data captured by an optical scan;
displaying part configured to display the formed 2-dimensional image; and
operation part configured to specify a position on said displayed 2-dimensional image, wherein said projection position changing part is configured to change the display position of said fixation target to the position specified by said operation part,
wherein when macula area of the fundus oculi is specified by said operation part, said projection position changing part is configured to determine whether or not the formed tomographic image includes a concave portion, extract an image region of which the concave portion is in the central position, about the tomographic image including the concave portion, and instruct said fixation target projection part to project said fixation target onto the position on the fundus oculi based on the extracted image region as the macula area,
wherein said second image forming part is configured to form a new tomographic image to be substantially centered at the concave portion of the fundus oculi of an eye, the eye being fixated by the projected fixation target.
2. A fundus observation device according to claim 1, wherein said projection position changing part is configured to switch said display position among a plurality of positions so as to project said fixation target onto the position when operated by said operation part.
3. A fundus observation device according to claim 1, wherein said second image forming part is configured to form the tomographic image to be substantially centered at the position on the fundus oculi of an eye corresponding to the position specified by said operation part, the eye being fixated by the fixation target whose display position has been changed by said projection position changing part.
4. A fundus observation device according to claim 1, wherein said projection position changing part is configured to extract an image region of which the deepest portion of the concave portion is in the central position, and instruct said fixation target projection part to project said fixation target onto the position on the fundus oculi based on the extracted image region, and said second image forming part is configured to form a new tomographic image to be substantially centered at the concave portion of the fundus oculi of an eye, the eye being fixated by the projected fixation target.
5. A fundus observation device according to claim 1, wherein when the tomographic image does not include a concave portion,
said projection position changing part is configured to change the projection position of the fixation image,
said second image forming part is configured to form new tomographic image based on the fixation position which is changed, and
said projection position changing part is configured to determine whether or not the newly formed tomographic image includes the concave portion.
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Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:FUKUMA, YASUFUMI;OTSUKA, HIROYUKI;YUMIKAKE, KAZUHIKO;AND OTHERS;REEL/FRAME:019276/0261