JP3423377B2 - Fundus camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera for controlling the voltage applied to a light source to correct the amount of illumination light. 2. Description of the Related Art A conventional fundus camera having such a function obtains an appropriate fundus image because there are individual differences in reflectance, refractive power, pupil diameter, etc. of the fundus of an eye to be examined. For this purpose, the illumination light amount of the photographing light source is corrected by controlling the voltage applied to the light source and the like. However, the emission spectrum of the photographing light source has a different emission intensity distribution according to the applied voltage. Therefore, if the fundus of the same eye to be examined is illuminated with different amounts of light in the conventional apparatus, the obtained fundus images will differ not only in brightness but also in color, which hinders proper diagnosis. FIG. 3 shows the spectral intensity distribution of the photographing light source 13 when the applied voltage is 80 V and 300 V, and the wavelength is 550.
The intensity of nm is standardized as 1. According to this, when the applied voltage is 80 V, the imaging light source 13 is 600 nm.
It has a strong emission spectrum in the region of ~ 700 nm and around 450-500 nm. On the other hand, when the applied voltage is 300 V, there is no strong emission spectrum on the long wavelength side,
It has a large emission spectrum at ~ 600 nm. For this reason, a fundus image having a different color is recorded depending on the light emission amount of the imaging light source 13. An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a fundus camera capable of recording a fundus image of a unique color even when the illumination light amount is changed. According to the present invention, there is provided a fundus camera for controlling the voltage applied to a light source for photographing to correct the amount of illumination light.
An imaging unit that captures a fundus image obtained from a light beam reflected by the fundus of the eye to be examined; an image storage unit that stores a fundus image captured by the imaging unit; and an applied voltage that controls an applied voltage to the imaging light source A control unit, a table storing data corresponding to a spectral intensity distribution of the imaging light source which changes according to the applied voltage, and data corresponding to applied voltage information obtained from the applied voltage control unit, read from the table. Arithmetic processing means for correcting the color balance of the fundus image stored in the image storage means using the data. The fundus camera having the above configuration corrects the color balance of the fundus image based on the voltage applied to the light source when controlling the voltage applied to the light source and correcting the illumination light amount. FIG. 1 is a block diagram of a reference example, in which a perforated mirror 2, a focus lens 3, and an image are formed on an optical path L1 behind an objective lens 1 facing an eye E to be inspected. A lens 4, a quick return mirror 5, and a film 6 are arranged, and an observation surface 7 is provided on an optical path L 2 in the reflection direction of the quick return mirror 5.
Are arranged, and observation means 8 such as an eyepiece is connected to the observation surface 7. On the optical path L3 in the incident direction of the perforated mirror 2, a relay lens 9 is selectively inserted into the optical path L3.
A plurality of optical filters 10a to 10c, a mirror 11, a condenser lens 12, a photographing light source 13 including a strobe tube,
Condenser lenses 14 and 15, an observation light source 16 composed of a halogen lamp, and a reflector 17 are arranged, and an output of an applied voltage control unit 18 is connected to the imaging light source 13. Here, the optical filters 10a to 10c have different spectral transmission characteristics, and are selectively inserted into the optical path L3 by switching means (not shown). This switching means is also operated by the applied voltage control means 18. . When observing the fundus Er, the optical filter 10a
-10c are retracted from the optical path L3. The light beam from the observation light source 16 moves to the left along with the light beam reflected by the reflector 17, passes through the condenser lenses 14, 15, and 12, is deflected by the mirror 11, is condensed by the relay lens 9 on the perforated mirror 2, and is reflected. And the fundus of the eye E through the objective lens 1
Illuminates Er. The reflected light beam here passes through the same optical path L1,
The light passes through the focus lens 3 and the imaging lens 4, is reflected by the quick return mirror 5, forms an image on the observation surface 7 as a fundus image, is projected on the observation means 8, and is observed by the photographer. At the time of photographing the fundus Er, the optical filters 10a to 10c having an appropriate spectral transmittance are selected and inserted into the optical path L3, the quick return mirror 5 is retracted from the optical path L1, and the voltage is controlled by the applied voltage control means 18. The light source 13 emits light by applying the voltage, and the fundus image is recorded on the film 6. When the amount of light emitted from the light source 13 for photography is determined by observing the fundus Er, the applied voltage control means 18 determines the amount of voltage applied to the light source 13 for photography and outputs it to switching means (not shown) as applied voltage information. I do. Based on this information, the switching means selects the optical filters 10a to 10c having appropriate spectral transmission characteristics and inserts them into the optical path L3. And
The applied voltage control means 18 applies a voltage to the imaging light source 13 to emit light. The luminous flux from the imaging light source 13 is converted into a luminous flux having an appropriate wavelength distribution by the optical filters 10a to 10c to illuminate the fundus Er, and a fundus image with a color balance is recorded on the film 6. FIG. 2 is a block diagram of the embodiment. A perforated mirror 22, a focus lens 23, and an imaging lens 2 are provided on an optical path L4 behind an objective lens 21 facing the eye E to be inspected.
4. The quick return mirror 25 and the film 26 are arranged, and the optical path L5 in the reflection direction of the quick return mirror 25 is provided.
On the top, the observation surface 27, the field lens 28, the mirror 2
9, an imaging lens 30, and an image sensor 31 are arranged.
On the optical path L6 in the incident direction of the perforated mirror 22, the relay lens 32, the mirror 33, the condenser lens 34, the photographing light source 35, the condenser lenses 36 and 37, and the observation light source 3
8. A reflector 39 is provided. The output of the image sensor 31 is sequentially connected to an image storage unit 40, an arithmetic processing unit 41, and a display unit 42 such as a television monitor. The arithmetic processing unit 41 includes a spectral intensity distribution table 43, an applied voltage control unit 4
4. It is sequentially connected to the photographing light source 25. here,
The imaging light source 35 has a different spectral intensity distribution with respect to the applied voltage as shown in FIG. 3, and these pieces of information are stored in the spectral intensity distribution table 43. At the time of fundus observation, the light beam from the observation light source 38 travels to the left along with the light beam reflected by the reflector 39, passes through the condenser lenses 36, 37 and 34, is reflected by the mirror 33, and is reflected by the relay lens 32 on the perforated mirror 22. And irradiates the fundus Er of the eye E through the objective lens 21. The reflected light flux here returns along the same optical path,
The light is reflected by the focus lens 23, the image forming lens 24, and the quick return mirror 25, forms an image near the field lens 28, forms an image on the image sensor 31 as a fundus image via the mirror 29 and the image forming lens 30, and stores the image. The moving image is displayed on the display means 42 through the means 40 and the arithmetic processing means 41. While observing the display means 42, the photographer selects an imaging part of the fundus and determines the light emission amount of the imaging light source 35. With this determination, the applied voltage control unit 44 sets an applied voltage to the imaging light source 35 and outputs the applied voltage to the spectral intensity distribution table 43 as applied voltage information. The spectral intensity distribution table 43 stores the imaging light source 3 corresponding to the set applied voltage.
5 is output to the arithmetic processing means 41. When a voltage is applied to the photographing light source 35 by the applied voltage control means 44 and the photographing light source 35 emits light, the image storage means 40 stores the fundus image and outputs it to the arithmetic processing means 40 as image data. . The arithmetic processing unit 41 performs image processing based on the spectral intensity distribution information from the spectral intensity distribution table 43 to correct the color balance of the fundus image, and displays the fundus image on the display unit 42. When the fundus image is recorded on the film surface 26, the quick return mirror 25 is used.
Is retracted from the optical path L4, and the imaging light source 35 emits light. As described above, the fundus camera according to the present invention corrects the color balance of the fundus image according to the amount of light emitted from the photographing light source, so that a fundus image with a natural color can be obtained. Can be

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a reference example. FIG. 2 is a configuration diagram of an embodiment. FIG. 3 is a spectral intensity distribution diagram with respect to an applied voltage of a photographing light source. [Description of Signs] 25 Quick return mirror 26 Film 27 Observation surface 31 Imaging device 35 Imaging light source 38 Observation light source 40 Image storage unit 41 Operation processing unit 42 Display unit 44 Applied voltage control unit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-92640 (JP, A) JP-A-1-300924 (JP, A) JP-A-1-149672 (JP, A) JP-A-5-95 68213 (JP, A) JP-A-2-1533692 (JP, A) JP-A-60-54589 (JP, A) JP-A-1-170438 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61B 3/00-3/16

Claims (1)

(57) [Claim 1] In a fundus camera that corrects an illumination light amount by controlling a voltage applied to a light source for photographing, captures a fundus image obtained from a light flux reflected on the fundus of the eye to be inspected. Imaging means for performing
An image storage unit that stores a fundus image captured by the imaging unit; an application voltage control unit that controls an applied voltage to the imaging light source; and a spectral intensity distribution of the imaging light source that changes according to the applied voltage. A table storing the corresponding data and data corresponding to the applied voltage information obtained from the applied voltage control unit are read out from the table, and the color balance of the fundus image stored in the image storage unit is corrected using the data. A fundus camera, comprising: