JP7033975B2 - Ophthalmic device and its corneal shape measurement method - Google Patents

Description

The present invention relates to an ophthalmic apparatus for measuring the corneal shape of an eye to be inspected and a method for measuring the corneal shape thereof.

For example, an ophthalmic device that measures the shape of the cornea of the eye to be inspected, such as a corneal topographer device, is well known. This ophthalmic apparatus projects concentric and multiple placidling lights onto the cornea, and acquires a photographed image (anterior eye image) obtained by photographing the cornea. Then, the ophthalmic apparatus analyzes the captured image to detect a platidling image which is a reflection image of the platidling light, that is, a platidling image composed of a plurality of concentric ring images, and obtains this platidling image. Based on this, the corneal shape of the cornea [corneal curvature of almost the entire area of the cornea, etc.] is measured.

In such an ophthalmic apparatus, various efforts have been made to accurately measure the corneal shape of the eye to be inspected.

For example, the ophthalmic apparatus described in Patent Document 1 performs multiple imaging of a cornea on which the same pattern of platidling light is projected, and analyzes the corneal shape from a plurality of captured images obtained by the multiple imaging. Select a platidling image in which the required brightness is secured, and calculate the corneal shape based on this platidling image.

Further, the ophthalmologic apparatus described in Patent Document 2 performs pre-measurement (projection of an index and imaging of the cornea) on a narrow region on the cornea, and obtains the corneal curvature of this region and the light amount level of the reflected image in advance. Then, the ophthalmic apparatus described in Patent Document 2 determines the light amount of the projected light of the platidling light at the time of the main measurement based on the acquisition result of the above-mentioned corneal curvature and the light amount level, and determines the light amount of the platidling light for the main measurement (platidating light). By performing projection and imaging of the cornea), the shape of the cornea of the eye to be inspected is calculated.

Japanese Unexamined Patent Publication No. 2007-215950 Japanese Unexamined Patent Publication No. 2012-135536

In a plaid ring image obtained by an ophthalmic device that measures a wide range on the cornea, such as a corneal topographer device, the state of the ring image obtained by the site on the cornea changes. For example, a ring image located near the center of the cornea has a pupil as a background, so that the contrast with respect to the background is high.

On the other hand, since the ring image located in the radial middle portion of the cornea has the iris as the background, the contrast is lowered by the reflection of the iris. Therefore, in order to optimally detect the ring image located on the iris, the amount of ring light is suppressed as compared with the case of detecting the ring image located on the pupil, so that the reflection of the ring light by the iris is suppressed. It is desirable to take a picture of the cornea with.

Further, in the ring image located on the outer peripheral portion of the cornea, a part of the image is interrupted or the image becomes dark due to vignetting caused by eyelashes or the like. Therefore, in order to optimally detect the ring image of the part vignetting due to the eyelashes, it is desirable to photograph the cornea with the amount of ring light increased as compared with the case of detecting the ring image located on the pupil. ..

As described above, in each ring image of the purachido ring image, the optimum amount of ring light for detection differs depending on the portion on the cornea. Therefore, even if the cornea is photographed a plurality of times or the cornea is pre-measured as in the ophthalmologic apparatus described in Patent Document 1 and Patent Document 2, all the ring images of the platidling image are optimally detected. That is difficult. Therefore, the ophthalmic apparatus described in Patent Document 1 and Patent Document 2 cannot measure the corneal shape with high accuracy.

Therefore, it is conceivable to set the amount of light of the ring light projected for each part on the cornea in advance, that is, to individually set the amount of light of each ring light of the plaid ring light according to the part on the cornea. .. However, the above method is not optimal because the pupil diameter, the reflectance of the iris, the degree of eyelashes, etc. vary from person to person and further differ depending on the measurement conditions.

Further, when the reflectance of the ring light by the iris is low when detecting the ring image on the iris, it is easier to obtain a ring image with good contrast by increasing the amount of the ring light. Furthermore, if the eyelashes are short when detecting the ring image located on the outer periphery of the cornea, or if the eyelids are sufficiently opened and the eyelashes do not hang, if the amount of ring light is too high, the brightness value of the ring image will be increased. The peak becomes saturated, which causes deterioration of the detection accuracy of the ring image. Furthermore, even when detecting a ring image on the pupil, the amount of light is lower than usual in the case of an eye to be inspected where reflection of ring light is likely to occur, such as an eye to be inspected in which an intraocular lens is inserted. It is less likely to be affected by unnecessary reflection of the ring light when the ring light is projected in.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ophthalmic apparatus capable of measuring the corneal shape of an eye to be inspected with high accuracy and a method for measuring the corneal shape thereof.

The ophthalmic apparatus for achieving the object of the present invention includes a pattern light projection optical system that projects a pattern light for measuring the shape of the cornea onto the cornea of the eye to be inspected, and a cornea on which the pattern light is projected from the pattern light projection optical system. A corneal imaging image acquisition unit that captures a corneal imaging image including a reflected image of the pattern light, and a projection control unit that changes the amount of pattern light projected onto the cornea from the pattern light projection optical system at least once. , Each time the amount of pattern light is changed by the projection control unit, the acquisition control unit that re-executes the acquisition of the corneal image by the corneal image acquisition unit and the corneal image acquisition unit acquire the pattern light according to the amount of light. Based on the detection result of the brightness value detection unit that detects the brightness value of the reflected image from the corneal image, and the detection result of the brightness value detection unit, the optimum corneal image for detecting the part is selected by the amount of light for each part in the reflection image. A selection unit selected from the corneal imaging images of the above, a site detection unit that detects the site from the corneal imaging image selected by the selection unit based on the selection result of the selection unit, and a site by the site detection unit. It is provided with a corneal shape calculation unit that calculates the corneal shape of the eye to be inspected based on the detection result for each.

According to this ophthalmic apparatus, it is possible to reduce the detection error of the reflected image of the pattern light and measure the corneal shape accurately (high accuracy).

In the ophthalmologic apparatus according to another aspect of the present invention, the cornea in which the SN ratio of the luminance value is the highest in the corneal photographed image in which the luminance value of the moiety is smaller than the predetermined saturation threshold value for each site. Select the captured image from the corneal captured images according to the amount of light. This makes it possible to select an optimal corneal imaging image for detecting a portion in the reflected image.

In the ophthalmic apparatus according to another aspect of the present invention, the pattern light projection optical system projects the platidling light composed of a plurality of concentric ring lights as the pattern light onto the eye to be inspected, and the corneal imaging image acquisition unit performs. , As a reflection image, a corneal imaging image including a platidling image composed of a plurality of concentric ring images is acquired, and the brightness value detection unit obtains a plurality of ring images in the platidling image for each corneal imaging image. The brightness value is detected, the selection unit selects the most suitable corneal imaging image for ring image detection from the corneal imaging images by light intensity, and the site detection unit selects each ring image. The ring image is detected from the corneal photograph image selected by the unit, and the corneal shape calculation unit calculates the corneal shape based on the detection result for each ring image. As a result, the detection error of each ring image of the purachido ring image can be reduced, and the corneal shape can be measured accurately.

In the ophthalmic apparatus according to another aspect of the present invention, the pattern light projection optical system projects the ring light as the pattern light onto the eye to be inspected, and the corneal imaging image acquisition unit acquires the corneal imaging image including the ring image as the reflection image. Then, the brightness value detection unit detects the brightness values of a plurality of parts in the ring image along the circumferential direction of the ring image for each corneal image, and the selection part detects the brightness values of each part in the ring image. The most suitable corneal imaging image for detection is selected from the corneal imaging images according to the amount of light, and the site detection unit detects the site from the corneal imaging image selected by the selection unit for each site. As a result, even when the ring image straddles the pupil of the eye to be inspected and the iris, the ring image can be detected with high accuracy.

In the ophthalmic apparatus according to another aspect of the present invention, the pattern light projection optical system projects pattern light, which is invisible light, onto the eye to be inspected.

The method for measuring the corneal shape of an ophthalmic apparatus for achieving the object of the present invention is a pattern light projection step of projecting a pattern light for measuring the corneal shape onto the cornea of the eye to be inspected, and a pattern light projection step in which the pattern light is projected. Projection control that changes the amount of patterned light projected onto the cornea at least once in the corneal imaging image acquisition step of photographing the existing cornea and acquiring the corneal imaging image including the reflected image of the pattern light, and the pattern light projection step. Each time the light intensity of the pattern light is changed by the step and the projection control step, the acquisition control step for re-executing the corneal imaging image acquisition step and the corneal imaging image acquired for each pattern light intensity in the corneal imaging image acquisition step. From, based on the detection result of the brightness value detection step that detects the brightness value of the reflected image and the detection result of the brightness value detection step, the optimum reflected image for detecting the part is obtained for each part in the reflected image. A selection step to select from among, a site detection step that detects a site from the reflection image selected in the selection step for each site based on the selection result of the selection step, and a detection result for each site by the site detection step. Based on this, it has a corneal shape calculation step for calculating the corneal shape of the eye to be inspected.

The present invention can measure the corneal shape of the eye to be inspected with high accuracy.

It is an optical layout drawing which showed the arrangement of the optical system of the ophthalmic apparatus of this invention. It is a front view of the purachido ring seen from the side to be examined. It is a front view of the light receiving surface of the area sensor of the 2nd light receiving optical system. It is a functional block diagram of the integrated control unit of an ophthalmic apparatus. It is explanatory drawing for demonstrating the purachido ring light according to the amount of light. It is explanatory drawing which showed an example of the photographed image data for each light amount which is the detection target of a luminance value by a luminance value detection unit. It is a graph which showed the detection result of the luminance value along the meridian direction of the photographed image data of light amount "small". It is a graph which showed the detection result of the luminance value along the meridian direction of the photographed image data of light amount "medium". It is a graph which showed the detection result of the luminance value along the meridian direction of the photographed image data of light amount "large". It is explanatory drawing for demonstrating the detection of each ring image by a part detection part. It is a flowchart which shows the flow of the measurement process of the corneal shape of the eye to be examined by the ophthalmic apparatus. It is explanatory drawing of the photographed image data of 2nd Embodiment. It is explanatory drawing for demonstrating the detection of the luminance value for each photographed image data by the luminance value detection unit of 2nd Embodiment. It is a graph which showed the detection result of the luminance value along the kth detection line in FIG. 13 of each photographed image data. It is a graph which showed the detection result of the luminance value along the nth detection line in FIG. 13 of each photographed image data. It is explanatory drawing for demonstrating the detection for each part of the ring image by the part detection part of 2nd Embodiment. It is explanatory drawing for demonstrating the correspondence relationship between the part of a ring image, and the photographed image data detected by the part detection part of 2nd Embodiment.

[Structure of Ophthalmic Appliance of First Embodiment]
FIG. 1 is an optical layout diagram showing an arrangement of an optical system of the ophthalmic apparatus 10 of the present invention. Here, the X-axis direction in the figure is the left-right direction (the eye width direction of the subject E) with respect to the subject, the Y-axis direction is the vertical direction, and the Z-axis direction is before approaching the subject. It is a front-back direction (also called a working distance direction) parallel to the direction and the rear direction away from the subject.

As shown in FIG. 1, the ophthalmic apparatus 10 is a multifunction device that measures both the eye characteristics of the eye to be inspected E and the corneal shape of the cornea Ec in the anterior segment of the eye to be inspected E. In this embodiment, as the measurement of the eye characteristics of the eye to be inspected E, the measurement of the optical refractive power and the wavefront aberration of the eyeball of the eye to be inspected E will be described as an example. Further, the measurement of the corneal shape of the present embodiment includes the measurement of the corneal wave surface aberration obtained from the corneal shape in addition to the measurement of the corneal curvature and the radius of curvature of almost the entire region of the corneal Ec.

The ophthalmic apparatus 10 includes an eye characteristic measurement optical system 12, a corneal shape measurement optical system 14, an alignment optical system 16, and a fixative optical system 18.

[Ocular characteristic measurement optical system]
The eye characteristic measurement optical system 12 includes a measurement light projection optical system 20 and a first light receiving optical system 22. The measurement light projection optical system 20 projects the measurement light L1 for measuring eye characteristics onto the fundus Ef of the eye E to be inspected. The first light receiving optical system 22 receives the reflected light of the measurement light L1 reflected by the fundus Ef and outputs the eye characteristic measurement data D1.

<Measurement light projection optical system>
The measurement light projection optical system 20 includes a measurement light source 26, a collimeter lens 28, a polarization beam splitter 30, a dichroic mirror 32, a dichroic mirror 34, an objective lens 36, and a light source moving unit 38.

The measurement light source 26 emits, for example, the measurement light L1 in the near infrared wavelength region toward the collimator lens 28. As the measurement light source 26, for example, an SLD (Super luminescent diode), a laser light source, an LED (Light emitting diode), or the like is used. Further, the measurement light source 26 is movably held by the light source moving unit 38 along a direction parallel to the emission direction of the measurement light L1.

The collimator lens 28 converts the measurement light L1 incident from the measurement light source 26 into parallel light, and then emits the measurement light L1 to the polarization beam splitter 30.

The polarization beam splitter 30 reflects the P polarization component of the measurement light L1 incident from the collimator lens 28 toward the dichroic mirror 32. Further, the polarization beam splitter 30 transmits the S polarization component of the reflected light of the measurement light L1 incident from the fundus Ef incident from the dichroic mirror 32 and incidents it on the reflecting mirror 40 described later.

The dichroic mirror 32 reflects the measurement light L1 incident from the polarized beam splitter 30 toward the dichroic mirror 34, and reflects the reflected light of the measurement light L1 incident from the dichroic mirror 34 toward the polarized beam splitter 30. Further, the fixation target light L5 incident from the reflector 96 described later is transmitted and incident on the dichroic mirror 34.

The dichroic mirror 34 reflects the measurement light L1 and the fixation target light L5 incident from the dichroic mirror 32 toward the objective lens 36, and directs the reflected light of the measurement light L1 incident from the objective lens 36 toward the dichroic mirror 32. Reflects. Further, the dichroic mirror 34 transmits the reflected light of the later-described platidling light L2 incident from the objective lens 36 and emits the light toward the later-described half mirror 70, and the later-described XY alignment light incident from the half mirror 70. It passes through L4 and emits light toward the objective lens 36.

The objective lens 36 is commonly used in each optical system except the ring optical projection optical system 52 described later, and causes the measurement light L1, the XY alignment light L4, and the fixative target light L5 to be incident on the eye E to be inspected.

<First light receiving optical system>
The first light receiving optical system 22 shares the polarizing beam splitter 30, the dichroic mirrors 32, 34, and the objective lens 36 with the measurement optical projection optical system 20, and also shares the reflecting mirror 40, the lens 42, the collimator lens 43, and the Hartmann. It has a plate 44, an area sensor 46, and a sensor driving unit 48.

The reflecting mirror 40 reflects the reflected light of the measurement light L1 incident from the polarizing beam splitter 30 toward the lens 42. As a result, the reflected light of the measurement light L1 is converted into parallel light by the collimator lens 43 via the lens 42, and then incident on the Hartmann plate 44.

The Hartmann plate 44 has a plurality of microlenses arranged two-dimensionally, and the reflected light of the measurement light L1 incident from the lens 42 is divided into a plurality of divided lights and incident on the light receiving surface of the area sensor 46.

The area sensor 46 is, for example, a CMOS (complementary metal oxide semiconductor) type or CCD (Charge Coupled Device) type image pickup device. The area sensor 46 receives (impresses) a plurality of divided lights incident from the Hartmann plate 44, and obtains image data of a Hartmann image composed of a plurality of point images corresponding to each divided light to the fundus portion of the eye E to be inspected. It is output as the eye characteristic measurement data D1 of Ef to the integrated control unit 100 (see FIG. 4) described later.

The sensor drive unit 48 movably holds the collimator lens 43, the Hartmann plate 44, and the area sensor 46 along a direction parallel to the incident direction of the reflected light of the measurement light L1. The sensor driving unit 48 and the light source moving unit 38 described above are driven so that the measurement light source 26, the fundus Ef, and the area sensor 46 have a substantially conjugate positional relationship according to the refractive power of the eye E to be inspected.

[Corneal shape measurement optical system]
The corneal shape measuring optical system 14 includes a ring light projection optical system 52 and a second light receiving optical system 54. The ring light projection optical system 52 corresponds to the pattern light projection optical system of the present invention, and projects the placid ring light L2 onto the cornea Ec of the anterior eye portion of the eye E to be inspected. Further, the second light receiving optical system 54 corresponds to the corneal imaging image acquisition unit of the present invention, and photographs the corneal Ec (anterior eye portion) on which the platidling light L2 is projected, that is, the platidling light L2. The reflected light is imaged, and the photographed image data D2 of the anterior eye portion including the cornea Ec is output.

<Ring light projection optical system>
The ring light projection optical system 52 includes a purachido ring 58, a pair of light sources 60, and a pair of collimator lenses 62.

FIG. 2 is a front view of the purachido ring 58 as seen from the side of the eye to be inspected E. As shown in FIG. 2 and FIG. 1 described above, the plaid ring 58 is formed in a substantially annular shape and has a central opening 66, a plurality of ring patterns 68, and a pair of openings 69.

The central opening 66 is a circular opening hole formed in the central portion of the platid ring 58, and the center thereof substantially coincides with the optical axis of the objective lens 36. Through the central opening 66, the measurement light L1, the XY alignment light L4, and the fixative target light L5 are incident on the eye E to be inspected, and the reflected light reflected by the eye E to be inspected is incident on the objective lens 36.

The plurality of ring patterns 68 are formed concentrically around the optical axis of the objective lens 36, and each of them transmits light. Further, on the back surface side (objective lens 36 side) of the platid ring 58, a plurality of LEDs 58a (various known light sources other than LEDs may be used) are arranged along each ring pattern 68.

Each ring pattern 68 is illuminated by invisible light (eg, near-infrared light) emitted from each LED 58a. As a result, as the pattern light for measuring the shape of the cornea of the present invention, the plaid ring light L2 composed of invisible light transmitted through each ring pattern 68 is projected onto the cornea Ec of the eye E to be inspected and reflected by the cornea Ec. The reflected light of the platidling light L2 is incident on the objective lens 36. The wavelength range of the purachido ring light L2, which is invisible light, is not particularly limited.

The LED 58a of the present embodiment changes the amount of illumination light of each ring pattern 68, that is, the amount of light of the platidling light L2 incident on the eye E to be inspected, under the control of the integrated control unit 100 (see FIG. 4) described later.

The pair of openings 69 are formed on the circumference of, for example, the third (or other than the third) ring pattern 68 from the inside to the outside of the platid ring 58.

The pair of light sources 60 are provided on the back surface side of the purachido ring 58 corresponding to the pair of openings 69, respectively. The pair of light sources 60 emit Z-alignment light L3 toward the pair of collimator lenses 62, respectively.

The pair of collimator lenses 62 make the Z alignment light L3 incident from the pair of light sources 60 into parallel light, and then emit the Z alignment light L3 toward the pair of openings 69. As a result, the pair of Z-aligned lights L3 that have passed through the pair of openings 69 are projected onto the cornea Ec of the eye E to be inspected. Then, the reflected light of the pair of Z-aligned lights L3 reflected by the cornea Ec of the eye E to be inspected is incident on the objective lens 36 together with the reflected light of the pltedling light L2 described above.

[Second light receiving optical system]
Returning to FIG. 1, the second light receiving optical system 54 shares the dichroic mirror 34 and the objective lens 36 with the measurement optical projection optical system 20, and also includes a half mirror 70, a relay lens 72, an imaging lens 74, and an area. It has a sensor 76 and.

The half mirror 70 reflects the XY alignment light L4 incident from the reflecting mirror 84 described later toward the dichroic mirror 34. Further, the half mirror 70 transmits the reflected light of the placidling light L2, the pair of Z alignment light L3, and the XY alignment light L4 incident from the dichroic mirror 34 and incidents them on the relay lens 72. As a result, each reflected light is incident on the light receiving surface of the area sensor 76 via the relay lens 72 and the imaging lens 74.

[Alignment optical system]
The alignment optical system 16 shares the dichroic mirror 34, the objective lens 36, and the half mirror 70 with the second light receiving optical system 54, and has an alignment light source 80, a lens 82, and a reflecting mirror 84.

The alignment light source 80 emits the XY alignment light L4 toward the lens 82. After passing through the lens 82, the XY alignment light L4 is projected onto the corneal Ec of the eye E to be inspected as parallel light through the reflector 84, the half mirror 70, the dichroic mirror 34, and the objective lens 36. Then, the reflected light of the XY alignment light L4 reflected by the corneal Ec enters the light receiving surface of the area sensor 76 via the objective lens 36, the dichroic mirror 34, the half mirror 70, the relay lens 72, and the imaging lens 74. Will be done.

The area sensor 76 is a CCD type or CMOS type image pickup device. The area sensor 76 is arranged so as to be conjugated with the reflection image on the corneal surface of the eye E to be inspected when the operating distance of the ophthalmic apparatus 10 is set to a predetermined distance.

FIG. 3 is a front view of the light receiving surface of the area sensor 76 of the second light receiving optical system 54. As shown in FIG. 3, the light receiving surface of the area sensor 76 is paired with the platidling image 86, which is a reflected image based on the reflected light of the platidling light L2, superimposed on the anterior segment image by the imaging lens 74. A pair of bright spot images B1 which are reflection images based on the reflected light of the Z alignment light L3 and a bright spot image B2 which is a reflection image based on the reflected light of the XY alignment light L4 are imaged.

The area sensor 76 captures an image of the anterior eye portion of the eye to be inspected E including a placid ring image 86, a pair of bright spot images B1, and a bright spot image B2, and captures image data D2 in a controlled control unit 100 (FIG. 4) Output to. The captured image data D2 corresponds to the captured corneal image of the present invention.

The plaid ring image 86 corresponds to a reflection image (by the cornea Ec) of the pattern light of the present invention, and is a multiple ring image composed of a plurality of concentric (8 in this embodiment) ring images 87. be. In the present embodiment, the plaid ring image 86 is composed of an eight-layered ring image 87, but it may be composed of a double-layered or more ring image 87. Hereinafter, each ring image 87 is referred to as a first ring image 87, a second ring image 87, ... An eighth ring image 87 from the inside to the outside of the plated ring image 86. Further, when each ring image 87 is not particularly distinguished, it is simply described as "ring image 87".

Both the third ring image 87 (another ring image 87 is also possible) and the pair of bright spot images B1 show the alignment state of the ophthalmologic apparatus 10 with respect to the eye E to be inspected in the Z-axis direction. Specifically, if the distance between the pair of bright spot images B1 and the diameter of the third ring image 87 match, the alignment in the Z-axis direction is adjusted, and conversely, if they do not match, the Z-axis direction. Is out of alignment (see JP-A-2011-115387).

The detection method for detecting the alignment in the Z-axis direction is not limited to the above method. For example, a method of projecting a target onto the corneal Ec from two or more different distances and detecting alignment from the height ratio of each index image (magnification method), irradiating the corneal Ec with a light beam from an angle different from the optical axis. Then, a method of detecting the alignment based on the displacement of the reflected light beam from the apex of the cornea (optical axis method), and a method of detecting the alignment from the parallax of the captured images of the corneal Ec taken from two or more directions with different angles (stereo camera). Method), and a method of detecting alignment from the focus (contrast of captured image) of the second light receiving optical system 54 can be mentioned as an example.

The bright spot image B2 shows the alignment state of the ophthalmic apparatus 10 with respect to the eye E to be inspected in the X-axis direction and the Y-axis direction. Specifically, when the bright spot image B2 is located at the center of the area sensor 76, the alignment in the X-axis direction and the Y-axis direction is adjusted, and conversely, when it is not located at the center, the X-axis direction is adjusted. And at least one of them is out of alignment in the Y-axis direction (see JP-A-2011-115387).

[Fixation optics]
Returning to FIG. 1, the fixative optical system 18 projects the fixative target light L5 for the fixative or cloud fog of the eye E to be examined. The fixation optical system 18 shares the dichroic mirror 32, the dichroic mirror 34, and the objective lens 36 with the measurement optical projection optical system 20 described above, and also shares the light source 88, the lens 90, the fixation target 92, and the lens 94. And a reflecting mirror 96, and an optotype moving unit 98.

The light source 88 emits illumination light in the wavelength range of visible light toward the lens 90. This illumination light is made parallel by the lens 90 and then incident on the fixative 92.

The fixative 92 is, for example, a landscape or radiation pattern, which is illuminated from behind by the illumination light incident on the lens 90. As a result, the fixative light L5 is emitted from the fixative 92 toward the lens 94. The fixative light L5 is incident on the eye E to be inspected through the lens 94, the reflector 96, the dichroic mirror 32, the dichroic mirror 34, and the objective lens 36, and is projected onto the fundus Ef thereof.

The optotype moving unit 98 integrally moves the light source 88, the lens 90, and the fixative target 92 according to the refractive power of the eye E to be inspected. As a result, the eye E to be inspected can be fixed. Further, the optotype moving unit 98 performs cloud fog to eliminate the influence of the adjustment of the eye E to be inspected when measuring the refractive power of the eye to be inspected E.

[Structure of integrated control unit]
FIG. 4 is a functional block diagram of the integrated control unit 100 of the ophthalmic apparatus 10. As shown in FIG. 4, the integrated control unit 100 is an arithmetic circuit composed of various arithmetic units including, for example, a CPU (Central Processing Unit) or an FPGA (field-programmable gate array), a memory, and the like. In addition to the above-mentioned optical systems, an operation unit 102, a storage unit 104, a display unit 106, and an alignment drive unit 108 are connected to the integrated control unit 100. Then, the integrated control unit 100 comprehensively controls the operation of each unit of the ophthalmic apparatus 10 in response to the input operation to the operation unit 102 by the examiner.

The storage unit 104 stores the measurement results of the eye characteristics and the corneal shape of the eye E to be inspected, and also stores a measurement program (not shown) for executing the measurement by the ophthalmic apparatus 10. The display unit 106 displays the eye characteristics of the eye E to be inspected, the measurement result of the corneal shape, and the like. The alignment drive unit 108 moves each optical system of the ophthalmic apparatus 10 relative to the eye to be inspected E in each axial direction of the XYZ axes under the control of the integrated control unit 100, so that the ophthalmic apparatus is relative to the eye to be inspected E. 10 is auto-aligned.

By executing a measurement program (not shown) read from the storage unit 104, the integrated control unit 100 includes an eye characteristic measurement control unit 110, a first image acquisition unit 112, an eye characteristic calculation unit 114, and a corneal shape measurement control unit 116. It functions as a second image acquisition unit 118, an alignment detection unit 120, a ring image analysis unit 122, and a corneal shape calculation unit 126.

The eye characteristic measurement control unit 110 controls the measurement of the eye characteristic of the eye to be inspected E by the ophthalmic apparatus 10. The eye characteristic measurement control unit 110 controls the fixation optical system 18 to make the eye E to be inspected cloud fog (when measuring the eye refractive force), and the eye characteristic measurement optical system 12 (measurement light projection optical system 20 and the first eye characteristic measurement control unit 110). The light receiving optical system 22) is controlled to project the measurement light L1 onto the fundus Ef of the eye E to be inspected, image the reflected light of the measurement light L1, and output the eye characteristic measurement data D1.

The measurement of the eye characteristics of the eye E to be inspected is executed at an arbitrary timing different from the timing of the measurement of the corneal shape described later. Further, the measurement of the eye characteristics of the eye E to be inspected is not essential and may be omitted if unnecessary. In this case, by inputting the operation of stopping the measurement of the eye characteristics to the operation unit 102, the measurement of the eye characteristics of the eye to be inspected E by the ophthalmic apparatus 10 is omitted.

The first image acquisition unit 112 acquires the eye characteristic measurement data D1 of the fundus Ef output from the first light receiving optical system 22, and outputs the eye characteristic measurement data D1 to the eye characteristic calculation unit 114.

The eye characteristic calculation unit 114 analyzes the eye characteristic measurement data D1 input from the first image acquisition unit 112, and calculates eye characteristics such as the optical refractive power and eyeball wave surface aberration of the eye E to be inspected. Since the method for calculating the eye characteristics is a known technique (Japanese Patent Laid-Open No. 2011-115387), a specific description thereof will be omitted here. Then, the eye characteristic calculation unit 114 stores the calculation result of the eye characteristic of the eye to be inspected E in the storage unit 104 and displays it on the display unit 106.

The corneal shape measurement control unit 116 corresponds to the projection control unit and the acquisition control unit of the present invention, and controls the measurement of the corneal shape by the ophthalmic apparatus 10. The corneal shape measurement control unit 116 first controls the fixation optical system 18 to fix the eye E to be inspected, and also controls the ring light projection optical system 52 and the alignment optical system 16 to control the eye E to be inspected. A platidling light L2, a pair of Z-aligned optics L3, and an XY-aligned light L4 are projected onto the optometry Ec. Further, the corneal shape measurement control unit 116 controls the second light receiving optical system 54 to control the reflected light of each light, that is, the platidling image 86, the pair of bright spot images B1 and the bright spot image shown in FIG. The image of the point image B2 and the output of the captured image data D2 for alignment detection are executed.

Further, the corneal shape measurement control unit 116 controls the corneal shape measurement optical system 14 after the alignment is completed, and the ring light projection optical system 52 projects the plated ring light L2 onto the corneal Ec and the second light receiving optical system 54. The imaging (acquisition) of the platidling image 86 and the output of the captured image data D2 are repeatedly executed three times.

At this time, the corneal shape measurement control unit 116 controls the LED 58a of the ring light projection optical system 52, and the amount of light of the placid ring light L2 projected on the corneal Ec for the first time and the placid ring light projected for the second time. The amount of light of L2 and the amount of light of the platidling light L2 projected for the third time are made different. Specifically, in the present embodiment, the amount of light of the platidling light L2 projected on the cornea Ec is increased stepwise in three steps. The amount of light of the plaid ring light L2 projected on the cornea Ec at the first time is set to "small", the amount of light of the plaid ring light L2 projected on the cornea Ec at the second time is set to "medium", and the light amount of the plaid ring light L2 projected on the cornea Ec at the second time is set to "medium". The amount of light of the projected platidling light L2 is set to "large".

FIG. 5 is an explanatory diagram for explaining the purachido ring light L2 according to the amount of light. In the following description, it is assumed that the "pupil Ep" includes the pupil image in the captured image data D2, and the "iris Ei" includes the iris image in the captured image data D2.

As shown in FIG. 5, the light intensity “small” of the platidling light L2 is a ring image 87 which is a reflection image of the ring light L2a (indicated by the solid line in the figure) of the platidling light L2 projected on the iris Ei. Is adjusted to a light amount suitable for detecting from the captured image data D2. Further, the light amount “medium” of the platiding light L2 detects the ring image 87, which is a reflected image of the ring light L2a (indicated by a alternate long and short dash line in the figure) projected on the pupil Ep, from the captured image data D2. The amount of light is adjusted to be suitable for.

The light intensity "large" of the platidling light L2 is a photographed image data of a ring image 87 which is a reflection image of the ring light L2a (indicated by a dotted line in the figure) of the platiding ring light L2 projected on the outer peripheral portion of the cornea Ec. The amount of light is adjusted to be suitable for detection from D2. As described above, the ring light L2a projected on the outer peripheral portion of the cornea Ec is vignetted by the eyelash EL or the like. As a result, a part of the ring image 87 is interrupted or the image becomes dark. Therefore, the amount of light "large" is adjusted to an amount of light that can prevent the ring image 87 from being interrupted or the ring image 87 from becoming dark.

As described above, appropriate values are preset for each of the light amounts of the platidling light L2, such as the light amount "small", the light amount "medium", and the light amount "large", by an experiment or a simulation.

Returning to FIG. 4, the second image acquisition unit 118 constitutes the corneal imaging image acquisition unit of the present invention together with the above-mentioned second light receiving optical system 54, and the captured image data D2 from the second light receiving optical system 54. To get. When the second image acquisition unit 118 acquires the captured image data D2 for alignment detection from the second light receiving optical system 54 before the alignment by the alignment drive unit 108 described above, the second image acquisition unit 118 transfers the captured image data D2 to the alignment detection unit 120. Output.

Further, the second image acquisition unit 118 captures image data (“small”, “medium”, “large”) of the platidling light L2 from the second light receiving optical system 54 after alignment by the alignment drive unit 108 described later. D2 is sequentially acquired, and the acquired captured image data D2 is sequentially output to the ring image analysis unit 122. Hereinafter, the classification of the purachido ring light L2 according to the amount of light is simply abbreviated as "by the amount of light".

The alignment detection unit 120 analyzes the captured image data D2 for alignment detection input from the second image acquisition unit 118, and based on the positional relationship between the above-mentioned third ring image 87 and the pair of bright spot images B1. , Detects the alignment state of the ophthalmic apparatus 10 with respect to the eye E to be inspected in the Z-axis direction. Further, the alignment detection unit 120 detects the alignment state of the ophthalmic apparatus 10 with respect to the eye E to be inspected in the X-axis direction and the Y-axis direction based on the position of the bright spot image B2.

Then, the alignment detection unit 120 outputs the alignment detection result in each axis direction of the XYZ axes to the alignment drive unit 108. As a result, the alignment drive unit 108 executes the auto-alignment of the ophthalmic apparatus 10 with respect to the eye E to be inspected. Instead of executing the auto alignment, the alignment detection result by the alignment detection unit 120 may be displayed on the display unit 106, and the manual alignment may be performed to drive the alignment drive unit 108 in response to the input operation to the operation unit 102. good.

The ring image analysis unit 122 analyzes the captured image data D2 for each amount of light input from the second image acquisition unit 118, and captures the optimum image for detecting the ring image 87 for each ring image 87 of the plated ring image 86. The selection of the image data D2 and the detection of the ring image 87 from the selected captured image data D2 are performed. The ring image analysis unit 122 functions as a luminance value detection unit 123, a selection unit 124, and a ring image detection unit 125.

FIG. 6 is an explanatory diagram showing an example of captured image data D2 for each amount of light to be detected by the luminance value detecting unit 123. In FIG. 6, in order to clarify the pupil Ep and the iris Ei of the eye E to be inspected, the plated image 86 is omitted from the captured image data D2 shown by the reference numeral 6B as the captured image data D2 shown by the reference numeral 6A in FIG. It shows what was done.

As shown in FIG. 6, the luminance value detecting unit 123 detects the luminance value of each pixel in the captured image data D2 acquired for each light amount (for example, 0 to 255 in the case of 8-bit data). Then, the luminance value detection unit 123 outputs the detection result of the luminance value for each captured image data D2 to the selection unit 124. In the photographed image data D2, the reference numeral d in the drawing indicates an arbitrary radial direction passing through the center position (or tentative center position) of the platidling image 86 or the pupil Ep.

FIG. 7 is a graph showing the detection result (luminance value profile) of the luminance value along the meridian direction d of the captured image data D2 having a light intensity of “small”. FIG. 8 is a graph showing the detection result of the luminance value along the meridian direction d of the captured image data D2 having the light intensity “medium”. FIG. 9 is a graph showing the detection result of the luminance value along the meridian direction d of the captured image data D2 having a light intensity of “large”. The reference numeral ST in each figure indicates a saturation threshold value of the luminance value (for example, 255 in the case of 8-bit data).

As shown in FIGS. 7 to 9, in the detection result of the brightness value for each captured image data D2 by the brightness value detection unit 123, the change of the brightness value corresponding to the first ring image 87 to the eighth ring image 87 is shown. Waveforms V1 to V8 are included. Therefore, the luminance value of each ring image 87 can be detected for each captured image data D2 based on the luminance value detection result by the luminance value detecting unit 123. Then, the brightness value of each ring image 87 increases stepwise as the amount of light of the purachido ring light L2 increases.

Further, the reflectance of the platidling light L2 is low in the pupil Ep, whereas the reflectance of the platidling light L2 is high in the iris Ei. Therefore, in each captured image data D2, the iris Ei is higher than the background luminance value (luminance value of the pupil Ep) added to the luminance values of the first ring image 87 and the third ring image 87 located on the pupil Ep. The background brightness value (the brightness value of the iris Ei) added to the brightness value of the fourth ring image 87 to the eighth ring image 87 located in is higher.

Further, as shown in FIG. 5 described above, the ring light L2a of the plaid ring light L2 projected on the outer peripheral portion of the cornea Ec is vignetting by the eyelash EL. Therefore, in each captured image data D2, the brightness value of the eighth ring image 87 is lower than the brightness value of the fourth ring image 87 to the seventh ring image 87.

As shown in FIGS. 4 and 7 to 9, the selection unit 124 is a ring image of the plated ring image 86 based on the detection result of the luminance value for each captured image data D2 input from the luminance value detection unit 123. For each 87 (corresponding to a portion in the reflected image of the present invention), the optimum captured image data D2 for detecting the ring image 87 is selected from the captured image data D2 according to the amount of light.

Specifically, the selection unit 124 is in the captured image data D2 in which the luminance value (peak value) of the ring image 87 is smaller than the predetermined saturation threshold ST for each ring image 87 of the plated ring image 86. Then, the captured image data D2 having the highest SN ratio (signal-noise ratio) of this luminance value is selected from the captured image data D2 according to the amount of light. The SN ratio referred to here is [(luminance value of ring image 87) / (background brightness value)], in other words, it indicates the contrast ratio between the ring image 87 and the background image (pupil Ep or iris Ei).

The luminance values of the first ring image 87 to the third ring image 87 located on the pupil Ep are the photographed image data D2 (see FIG. 7) having a light amount of “small” and the photographed image data D2 (FIG. 8) having a light amount of “medium”. (See) is less than the saturation threshold ST, whereas the captured image data D2 (see FIG. 9) having a “large amount of light” exceeds the saturation threshold ST. Then, the SN ratio of each luminance value of the first ring image 87 to the third ring image 87 is higher in the photographed image data D2 having a light amount of "medium" than in the photographed image data D2 having a light amount of "small". Therefore, the selection unit 124 selects the captured image data D2 having a light intensity of "medium" as the optimum captured image data D2 for detecting the first ring image 87 to the third ring image 87, and detects the selected result as the ring image. Output to unit 125.

The luminance values of the 4th ring image 87 to the 7th ring image 87 located on the iris Ei are less than the saturation threshold ST in the captured image data D2 having a light intensity of "small", whereas the captured image data D2 has a light intensity of "medium". The saturation threshold ST is exceeded in the image data D2 and the captured image data D2 having a “large” light intensity. Therefore, the selection unit 124 selects the captured image data D2 having a light intensity of "small" as the optimum captured image data D2 for detecting the fourth ring image 87 to the seventh ring image 87, and detects the selected result as the ring image. Output to unit 125.

Each luminance value of the eighth ring image 87 vignetting by the eyelash EL is less than the saturation threshold ST in any of the captured image data D2 having the light amount “small”, the light amount “medium”, and the light amount “large”. Then, among the captured image data D2, the SN ratio of the luminance value of the eighth ring image 87 of the captured image data D2 having a “large” light intensity is the highest. Therefore, the selection unit 124 selects the photographed image data D2 having a large amount of light as the photographed image data D2 optimal for detecting the eighth ring image 87, and outputs the selection result to the ring image detection unit 125.

FIG. 10 is an explanatory diagram for explaining the detection of each ring image 87 by the ring image detection unit 125. As shown in FIG. 10, the ring image detection unit 125 corresponds to the site detection unit of the present invention, and is based on the selection result of the captured image data D2 for each ring image 87 input from the selection unit 124. For each image 87, the ring image 87 is detected from the captured image data D2 selected by the selection unit 124. The detection of the ring image 87 referred to here is the position detection of each position of the ring image 87, more specifically, the radius detection for each of a plurality of meridian directions d of the ring image 87.

Specifically, the ring image detection unit 125 detects the fourth ring image 87 to the seventh ring image 87 from the captured image data D2 having a light intensity of “small”, and the captured image data D2 to the first ring image having a light intensity of “medium”. The third ring image 87 is detected from 87, and the eighth ring image 87 is detected from the captured image data D2 having a “large” light intensity.

A known method is used for detecting each ring image 87 by the ring image detecting unit 125. For example, the detection of one ring image 87 will be described as an example. The ring image detection unit 125 detects the edge strength of each of a plurality of meridian directions d (for example, 360 lines at a 1 ° pitch) of the ring image 87, and detects the meridians. The edge strength of the ring image 87 is differentiated for each direction d to determine the position of the inflection point. Then, the ring image detection unit 125 determines the position (radius) of the inflection point of the ring image 87 in each meridian direction d as the position (radius) of the ring image 87. Similarly, the ring image detection unit 125 detects another ring image 87. The ring image detection unit 125 outputs the detection result of each ring image 87 to the corneal shape calculation unit 126. The method for detecting each ring image 87 is not limited to the above method, and various known methods may be used.

The corneal shape calculation unit 126 calculates the corneal shape and corneal wavefront aberration of the eye E to be inspected based on the detection result of each ring image 87 input from the ring image detection unit 125. Here, since the specific calculation method of the corneal shape and the corneal wavefront aberration is a known technique, a specific description thereof will be omitted. Then, the corneal shape calculation unit 126 stores the calculation result of the corneal shape of the eye to be inspected E in the storage unit 104 and displays it on the display unit 106. In addition, based on the alignment detection result in the Z-axis direction by the alignment detection unit 120 described above, the working distance error of the ophthalmic apparatus 10 at the time of measuring the corneal shape is detected, and this error detection result is fed back to the measurement result of the corneal shape. May be good.

[Action of ophthalmic appliances]
FIG. 11 is a flowchart showing the flow of the corneal shape measurement process of the eye E to be inspected (corresponding to the corneal shape measuring method of the ophthalmic apparatus of the present invention) by the ophthalmic apparatus 10 having the above configuration. In order to prevent the explanation from being complicated, the measurement of the eye characteristics of the eye to be inspected E will be omitted below.

As shown in FIG. 11, first, the corneal shape measurement control unit 116 of the integrated control unit 100 controls the fixative optical system 18 to project the fixative target light L5 onto the fundus Ef of the eye E to be inspected with a normal amount of light. By doing so, the eye E to be inspected is fixed (step S1).

Further, the corneal shape measurement control unit 116 controls the alignment optical system 16 and the ring light projection optical system 52, and the platid ring light L2, the pair of Z alignment light L3, and the XY alignment light are applied to the anterior eye portion of the eye E to be inspected. Project L4. Further, the corneal shape measurement control unit 116 controls the second light receiving optical system 54 to capture an image of each reflected light (reflected image) from the eye E to be inspected and output the captured image data D2 for alignment detection. .. The captured image data D2 for alignment detection is input from the second light receiving optical system 54 to the alignment detection unit 120 via the second image acquisition unit 118.

The alignment detection unit 120 analyzes the captured image data D2 for alignment detection input from the second image acquisition unit 118, and analyzes the positional relationship between the third ring image 87 and the pair of bright spot images B1 and the bright spot image. Based on the position of B2, the alignment state of the ophthalmologic apparatus 10 with respect to the eye E to be inspected in the XYZ axis direction is detected. Then, the alignment detection unit 120 outputs the detection result of the alignment state to the alignment drive unit 108. As a result, the alignment drive unit 108 executes the auto-alignment of the ophthalmic apparatus 10 with respect to the eye E to be inspected (step S2). As described above, manual alignment may be performed instead of auto alignment.

When the above alignment is completed, the corneal shape measurement control unit 116 projects the platidling light L2 with a “small” amount of light onto the cornea Ec by the ring light projection optical system 52 (LED58a) (step S3) and the second light receiving optics. The image of the cornea Ec by the system 54 and the output of the photographed image data D2 (step S4) are executed. As a result, the first captured image data D2 corresponding to the light amount “small” of the platidling light L2 is input from the second light receiving optical system 54 to the luminance value detection unit 123 via the second image acquisition unit 118. Note that step S3 corresponds to the pattern light projection step of the present invention, and step S4 corresponds to the corneal imaging image acquisition step of the present invention.

After the acquisition of the first captured image data D2, the corneal shape measurement control unit 116 controls the ring light projection optical system 52 (LED58a) to change the light intensity of the platiding light L2 from “small” to “medium”. (YES in step S5, step S6). Next, the corneal shape measurement control unit 116 projects the platidling light L2 having a “medium” amount of light onto the cornea Ec by the ring optical projection optical system 52 (step S3), and photographs the cornea Ec by the second light receiving optical system 54. The output of the captured image data D2 (step S4) is executed. As a result, the second captured image data D2 corresponding to the light amount “medium” of the platidling light L2 is input from the second light receiving optical system 54 to the luminance value detection unit 123 via the second image acquisition unit 118.

In the same manner thereafter, the corneal shape measurement control unit 116 projects the platidling light L2 having a “large” amount of light onto the cornea Ec by the ring optical projection optical system 52 (step S3), and the corneal Ec by the second light receiving optical system 54. And the output of the photographed image data D2 (step S4), and are executed (YES in step S5). As a result, the third captured image data D2 corresponding to the light amount “large” of the platidling light L2 is input from the second light receiving optical system 54 to the luminance value detection unit 123 via the second image acquisition unit 118. Note that step S5 corresponds to the projection control step and the acquisition control step of the present invention.

The luminance value detection unit 123, which receives the input of the captured image data D2 for each light amount from the second image acquisition unit 118, detects the luminance value for each captured image data D2 as shown in FIGS. 6 to 9 described above. (NO in step S5, step S7). As a result, the brightness value of each ring image 87 is detected for each captured image data D2. Therefore, step S7 corresponds to the luminance value detection step of the present invention. Then, the luminance value detection unit 123 outputs the luminance value detection result to the selection unit 124.

As shown in FIGS. 7 to 9 described above, the selection unit 124, which has received the input of the luminance value detection result from the luminance value detection unit 123, takes an optimum image for detecting the ring image 87 for each ring image 87. The image data D2 is selected from the captured image data D2 according to the amount of light (step S8, corresponding to the selection step of the present invention). As a result, the optimum captured image data for the detection of the ring image 87 located on the pupil Ep, the detection of the ring image 87 located on the iris Ei, and the detection of the eighth ring image 87 vignetting by the eyelash EL. D2 is selected. Then, the selection unit 124 outputs the selection result of the captured image data D2 for each ring image 87 to the ring image detection unit 125.

As shown in FIG. 10 described above, the ring image detection unit 125 that has received the input of the selection result from the selection unit 124 has a ring image from the captured image data D2 selected by the selection unit 124 for each ring image 87. 87 is detected (step S9, corresponding to the site detection step of the present invention). Thereby, the detection of each ring image 87 can be executed by using the captured image data D2 that is most suitable for each detection. As a result, each ring image 87 can be detected with high accuracy. Then, the ring image detection unit 125 outputs the detection result for each ring image 87 to the corneal shape calculation unit 126.

Upon receiving the input of the detection result of each ring image 87, the corneal shape calculation unit 126 calculates the corneal shape and the corneal wavefront aberration by using a known calculation method (step S10, corresponding to the corneal shape calculation step of the present invention). .. The calculation result of the corneal shape and the like by the corneal shape calculation unit 126 is stored in the storage unit 104 and displayed on the display unit 106 (step S11).

[Effect of this embodiment]
As described above, in the ophthalmic apparatus 10 of the present embodiment, the amount of light of the platidling light L2 projected on the cornea Ec is changed stepwise, and the captured image data D2 for each amount of light is acquired for each ring image 87. Since the optimum captured image data D2 for detection is selected and the detection is executed, the detection of each ring image 87 can be performed with high accuracy. As a result, the corneal shape of the eye E to be inspected can be measured with high accuracy. Further, since the captured image data D2 necessary for measuring the corneal shape can be obtained by this series of measurements, it is not necessary to repeat the measurement many times, and the burden on both the examiner and the subject can be reduced.

[Ophthalmic device of the second embodiment]
In the first embodiment, the measurement of the corneal shape when the center of the platidling image 86 substantially coincides with the center of the eye E (pupil Ep and iris Ei) is described as an example, but the second embodiment has been described. In the morphology, the measurement of the corneal shape when the plaid ring image 86 is eccentric with respect to the eye E (pupil Ep and iris Ei) to be inspected will be described.

FIG. 12 is an explanatory diagram of the captured image data D2 of the second embodiment. In addition, in FIGS. 12 and later, in order to prevent the drawings from being complicated, any one of the plurality of ring images 87 constituting the plated ring image 86 is shown, and the other ring images 87 are shown. Is omitted.

As shown in FIG. 12, when the platid ring image 86 is eccentric with respect to the eye E to be inspected, or when the shape of the pupil Ep is distorted although not shown, the ring image 87 has the same diameter. The ring image 87 has a portion located on the pupil Ep and a portion located on the iris Ei. Therefore, in the second embodiment, the optimum captured image data D2 for detecting the portion is selected from the captured image data D2 according to the amount of light for each portion in the ring image 87 along the circumferential direction of the ring image 87. do.

Since the second embodiment has basically the same configuration as the first embodiment, those having the same function or configuration as the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

The second image acquisition unit 118 of the second embodiment sequentially acquires the captured image data D2 for each amount of light from the second light receiving optical system 54, and the acquired captured image data D2, as in the first embodiment described above. Are sequentially output to the luminance value detection unit 123.

FIG. 13 is an explanatory diagram for explaining the detection of the luminance value for each captured image data D2 by the luminance value detecting unit 123 of the second embodiment. Since the method of detecting the luminance value from each captured image data D2 is common, the detection of the luminance value from one captured image data D2 will be described here.

The luminance value detection unit 123 of the second embodiment analyzes the captured image data D2 and detects the plated ring image 86 from the captured image data D2 by a known method, whereby an arbitrary ring in the plated ring image 86 is detected. The center position C of the image 87 (for example, the first ring image 87) is detected. Then, the luminance value detection unit 123 detects the luminance value of the pixel of the captured image data D2 along the detection line α for each of the plurality of detection lines α extending radially (radially) with respect to the center position C. The detection line α is substantially the same as the above-mentioned meridian direction d. Further, "1, 2, 3, ... k, ... n, ..." In the figure is a number of the detection line α. Then, the luminance value detecting unit 123 detects the luminance value of the remaining two captured image data D2 by the same method.

FIG. 14 is a graph showing the detection result (luminance value profile) of the luminance value along the k-th detection line α in FIG. 13 of each captured image data D2. FIG. 15 is a graph showing the detection results of the luminance values along the nth detection line α in FIG. 13 of each captured image data D2. As shown in FIGS. 14 and 15, the detection result of the luminance value along each detection line α includes the waveform V corresponding to the ring image 87. Therefore, for each captured image data D2, it is possible to detect the luminance value of the portion in the ring image 87 corresponding to each detection line α.

As in the first embodiment, the brightness value of the portion in the ring image 87 corresponding to each detection line α increases stepwise as the amount of light of the platiding light L2 increases. Further, when the ring image 87 intersects with the ring image 87 on the iris Ei, for example, as in the k-th detection line α, the reflectance of the platiding light L2 by the iris Ei becomes high, so that the brightness value of the ring image 87 becomes high. On the contrary, when it intersects with the ring image 87 on the pupil Ep as in the nth detection line α, the reflectance of the platiding light L2 by the pupil Ep becomes low, so that the brightness value of the ring image 87 becomes low. ..

The selection unit 124 of the second embodiment is a ring image 87 corresponding to each detection line α based on the detection result of the brightness value of each detection line α for each captured image data D2 input from the brightness value detection unit 123. For each part, the optimum photographed image data D2 for detecting the part is selected from the photographed image data D2 according to the amount of light.

For example, in the k-th detection line α, the luminance value of the ring image 87 in the captured image data D2 with a “small” light intensity is less than the saturation threshold ST, whereas the captured image data D2 with a “medium” light intensity and the “large light intensity”. The brightness value of the ring image 87 in both of the captured image data D2 exceeds the saturation threshold ST. Therefore, the selection unit 124 selects the captured image data D2 having a light intensity of “small” as the optimum captured image data D2 for detecting the portion of the ring image 87 corresponding to the k-th detection line α, and rings the selection result. Output to the image detection unit 125.

Further, in the nth detection line α, the luminance value of the ring image 87 in both the captured image data D2 having a “small” light intensity and the captured image data D2 having a “medium” light intensity is less than the saturation threshold ST, whereas the light intensity is less than the saturation threshold ST. The brightness value of the ring image 87 in the “large” captured image data D2 exceeds the saturation threshold ST. Then, the SN ratio of the brightness value of the ring image 87 is higher in the captured image data D2 having a light intensity of “medium” than in the captured image data D2 having a light intensity of “small”. Therefore, the selection unit 124 selects the captured image data D2 having a light intensity of “medium” as the optimum captured image data D2 for detecting the portion of the ring image 87 corresponding to the nth detection line α, and rings the selection result. Output to the image detection unit 125.

Similarly, the selection unit 124 outputs the selection result of selecting the optimum captured image data D2 for detecting the portion of the ring image 87 corresponding to the other detection line α to the ring image detection unit 125.

FIG. 16 is an explanatory diagram for explaining the detection of the ring image 87 by the ring image detection unit 125 of the second embodiment for each part. FIG. 17 is an explanatory diagram for explaining the correspondence between the portion of the ring image 87 and the captured image data D2 detected by the ring image detection unit 125 of the second embodiment. Here, the mth detection line α to the uth detection line α (including the nth detection line α) intersects the ring image 87 on the pupil Ep, and another detection line α (including the kth detection line α). ) Shall intersect the ring image 87 on the iris Ei.

As shown in FIGS. 16 and 17, the ring image detection unit 125 of the second embodiment is assigned to each detection line α based on the selection result of the captured image data D2 for each detection line α input from the selection unit 124. For each part of the corresponding ring image 87, the part is detected from the captured image data D2 selected by the selection unit 124. The detection of the site referred to here is the detection of the position of the site, more specifically, the detection of the radius of the site.

For example, in the range R1 (see FIG. 17) from the mth detection line α to the uth detection line α, the light intensity is “medium” by the selection unit 124, as in the nth detection line α shown in FIG. The captured image data D2 is selected. Therefore, the ring image detection unit 125 detects the portion of the ring image 87 corresponding to each of the mth detection line α to the u detection line α from the captured image data D2 having a light intensity of “medium”.

Further, in each detection line α in the range R2 (see FIG. 17) different from the range R1, the captured image having a “small” light intensity by the selection unit 124 is the same as the k-th detection line α shown in FIG. 14 described above. Data D2 is selected. Therefore, the ring image detection unit 125 detects the portion of the ring image 87 corresponding to the remaining detection line α from the captured image data D2 having a “small” light intensity.

Then, the ring image detection unit 125 outputs the detection result for each part of the ring image 87 corresponding to each detection line α to the corneal shape calculation unit 126.

Similarly, the ring image analysis unit 122 (luminance value detection unit 123, selection unit 124, and ring image detection unit 125) of the second embodiment of each portion of the other ring image 87 (not shown) of the plated ring image 86. The detection is executed, and the detection result of each part of the other ring image 87 is input to the corneal shape calculation unit 126.

The corneal shape calculation unit 126 of the second embodiment calculates the corneal shape and the corneal wavefront aberration of the eye E to be inspected, based on the detection result of each part for each ring image 87, as in the first embodiment.

The flow of the measurement processing of the eye characteristics and the corneal shape of the eye E to be inspected by the ophthalmic apparatus 10 of the second embodiment is basically the same as that of the first embodiment except for steps S7 to S9 shown in FIG. Is the same. That is, in the second embodiment, in step S7, the luminance value of the portion in the ring image 87 corresponding to each detection line α is detected for each captured image data D2. Further, in the second embodiment, in step S8, the optimum captured image data D2 is selected for each part of the ring image 87 corresponding to each detection line α, and in step S9, each part of the ring image 87 is detected. I do.

As described above, also in the second embodiment, the light amount of the platidling light L2 projected on the cornea Ec is changed stepwise, and the captured image data D2 for each light amount is acquired, and each part of the ring image 87 is obtained. By selecting and executing the detection of the captured image data D2 that is most suitable for the detection of the ring image 87, it is possible to detect each part of the ring image 87 with high accuracy. As a result, even when the platidling image 86 is eccentric with respect to the eye E to be inspected or the shape of the pupil Ep is distorted, the corneal shape of the eye E to be inspected can be measured with high accuracy.

[others]
In the above embodiment, the pattern light for measuring the corneal shape of the present invention has been described by taking the eight-layered plaid ring light L2 as an example, but the single or more double plaid ring light L2 (including the keratling light) has been described. , And the pattern light that can be used for measuring the corneal shape such as a predetermined pattern of dot light is not particularly limited.

In the above embodiment, the corneal shape measurement control unit 116 controls the ring light projection optical system 52 to change the amount of light of the platidling light L2 projected on the eye E to be inspected in three stages. The amount of light may be changed at least once, and the number of times is not particularly limited. Further, in this case, the corneal shape measurement control unit 116 controls the second light receiving optical system 54, and each time the amount of light of the platidling light L2 is changed, the corneal shape measurement control unit 116 captures the platidling image 86 and outputs the captured image data D2. And re-execute. As a result, at least two or more captured image data D2 for each amount of light can be obtained.

In the above embodiment, after all the acquisition of the captured image data D2 for each light amount is completed, the luminance value detection unit 123 starts the detection of the luminance value, but the luminance value is detected by the second light receiving optical system. It may be executed sequentially every time new captured image data D2 is acquired by 54.

In the above embodiment, the case where the eye refractive force or the like is measured as the eye characteristic of the eye to be inspected E by the ophthalmic apparatus 10 has been described as an example, but various eye characteristics other than the eye refractive force [intraocular pressure, optics of the fundus of the eye] have been described. Tomographic images, corneal endothelial cells, axial length, etc.] may be measured.

In the above embodiment, a composite machine for measuring both the eye characteristics of the eye to be inspected E and the corneal shape of the cornea Ec has been described as an example of the ophthalmic apparatus 10, but the ophthalmic apparatus of the present invention includes the cornea of the cornea Ec. It also includes a corneal shape measuring device such as a corneal topographer device that measures the shape, and a keratometer that measures the corneal curvature of a part of the corneal Ec.

10 ... Ophthalmic equipment,
14 ... Corneal shape measurement optical system,
52 ... Ring light projection optical system,
54 ... Second light receiving optical system,
58 ... Purachido ring,
86 ... Purachido ring image,
87 ... Ring statue,
100 ... Integrated control unit,
116 ... Corneal shape measurement control unit,
123 ... Luminance value detector,
124 ... Selection unit,
125 ... Ring image detector,
126 ... Corneal shape calculation unit

Claims (4)

A pattern light projection optical system that projects pattern light for measuring the shape of the cornea onto the cornea of the eye to be inspected,
A corneal imaging image acquisition unit that photographs the cornea on which the pattern light is projected from the pattern light projection optical system and acquires a corneal imaging image including a reflection image of the pattern light.
A projection control unit that changes the amount of the pattern light projected from the pattern light projection optical system onto the cornea at least once.
Each time the amount of the pattern light is changed by the projection control unit, the acquisition control unit that re-executes the acquisition of the corneal photograph image by the corneal photograph image acquisition unit, and the acquisition control unit.
A luminance value detecting unit that detects the luminance value of the reflected image from the corneal imaging image acquired by the corneal imaging image acquisition unit for each amount of the pattern light.
Based on the detection result of the luminance value detection unit, a selection unit for selecting the optimum corneal imaging image for detecting the region from the corneal imaging images according to the amount of light for each portion in the reflection image.
A site detection unit that detects the site from the corneal imaging image selected by the selection unit for each site based on the selection result of the selection unit.
A corneal shape calculation unit that calculates the corneal shape of the eye to be inspected based on the detection result for each site by the site detection unit.
Equipped with
The pattern light projection optical system projects ring light as the pattern light onto the eye to be inspected.
The corneal imaging image acquisition unit acquires the corneal imaging image including a ring image as the reflection image, and obtains the corneal imaging image.
The luminance value detecting unit detects the luminance values of a plurality of the portions in the ring image along the circumferential direction of the ring image for each corneal photographed image.
The selection unit selects, for each of the parts in the ring image, the corneal imaging image most suitable for detecting the portion from the corneal imaging images according to the amount of light.
An ophthalmic apparatus in which the site detection unit detects the site from the corneal imaging image selected by the selection unit for each site . The light amount of the corneal photographed image in which the SN ratio of the luminance value is the highest among the corneal photographed images in which the luminance value of the site becomes smaller than a predetermined saturation threshold value for each portion. The ophthalmologic apparatus according to claim 1, wherein the ophthalmologic apparatus is selected from another corneal imaging image. The ophthalmic apparatus according to claim 1 or 2 , wherein the pattern light projection optical system projects the pattern light, which is invisible light, onto the eye to be inspected. A pattern light projection step that projects a pattern light for measuring the shape of the cornea onto the cornea of the eye to be inspected,
A corneal imaging image acquisition step of photographing the cornea on which the pattern light is projected in the pattern light projection step and acquiring a corneal imaging image including a reflection image of the pattern light, and a corneal imaging image acquisition step.
A projection control step that changes the amount of the pattern light projected onto the cornea at least once in the pattern light projection step.
Each time the amount of the pattern light is changed by the projection control step, the acquisition control step for re-executing the corneal imaging image acquisition step and the acquisition control step.
A luminance value detection step for detecting the luminance value of the reflected image from the corneal imaging image acquired for each amount of the pattern light in the corneal imaging image acquisition step.
Based on the detection result of the luminance value detection step, a selection step of selecting the optimum reflected image for detecting the portion from the reflected images according to the amount of light for each portion in the reflected image, and a selection step.
A site detection step for detecting the site from the reflection image selected in the selection step for each site based on the selection result of the selection step.
A corneal shape calculation step for calculating the corneal shape of the eye to be inspected based on the detection result for each part by the site detection step, and a corneal shape calculation step.
Have,
The pattern light projection step projects ring light as the pattern light onto the eye to be inspected.
The corneal imaging image acquisition step acquires the corneal imaging image including a ring image as the reflection image.
The luminance value detection step detects the luminance values of a plurality of the portions in the ring image along the circumferential direction of the ring image for each corneal photographed image.
The selection step selects, for each of the sites in the ring image, the corneal imaging image optimal for detecting the site from the corneal imaging images according to the amount of light.
A method for measuring a corneal shape of an ophthalmic apparatus in which the site detection step detects the site from the corneal photograph image selected in the selection step for each site .

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