JPH02193644A - Ophthalmologic image pickup device - Google Patents

Abstract

PURPOSE:To always execute video picture recording with suitable exposure even when the reflection factor of an object is changed by providing a control part to detect charge quantity accumulated to a picture element group in the arbitrary spot of an image pickup element and to control a signal amplification factor to the output of an image pickup part according to illumination by a stroboscopic light source. CONSTITUTION:When an eyeground picture light flux L is made incident to an image pickup element 11, the charge is accumulated on the respective picture elements according to incident light quantity. Then, non-destruction reading is once executed by a charge level detector 13 and the charge level of the picture element group corresponding to an area A is observed. After that, the amplification factor is determined to the suitable level of a variable amplifier 14 by a control part 15 and all the picture elements are read again, passed through the variable amplifier 14 and sent to an analog picture recorder 16 as a picture signal S. Namely, the charge is once read and the amplification factor of the variable amplifier 14 is determined so that the video signal in the part of the area A needing the suitable exposure can be made suitable. Then, the video signal is made from the image pickup element 11 and recorded. Accordingly, the picture recording can be executed by the partially suitable level in one picture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ophthalmological imaging unit used for recording images of, for example, a fundus camera or a slit lamp.

[Prior Art] In the case of moving video recording using this kind of conventional photographic imaging device, the sensitivity adjustment function of the television camera (＾toIIlatic Galn Control) is controlled by lamp illumination.
l) is used to obtain the appropriate exposure. Furthermore, when recording a still image as a video using a bright strobe, the amount of light emitted by the strobe tube is determined in advance.

[Problem to be solved by the invention] However, since the reflectance of the subject changes, it is not always possible to record with the appropriate exposure.Especially, ophthalmological images have large brightness differences within the screen, so all parts of the screen cannot be recorded. It is impossible to properly video record.

FIG. 4 shows a fundus image formed on the image sensor, in which the papilla P is bright and the macula Q is dark. When the output of the image sensor is converted into a video signal using a variable amplifier with a constant signal amplification factor, both CR
cannot be viewed at optimal brightness on T, that is, on C
This is because the dynamic range that can be expressed on RT is not so wide.

The purpose of the present invention is to improve such conventional problems by making it possible to always record video with proper exposure even if the reflectance of the subject changes, and - even when there is a large difference in brightness within the screen, It is an object of the present invention to provide an ophthalmologic imaging device that can record this portion at an appropriate signal level.

[a! Means for Solving the Problem 1 In order to achieve the above object, the ophthalmological imaging device according to the present invention includes: a strobe light source; 2. A control unit that detects the amount of charge accumulated in a pixel group at an arbitrary location of the image sensor by illumination by the strobe light source and controls a signal amplification factor for the output of the image sensor. It is.

[Operation] The ophthalmological imaging device having the above-described configuration detects the brightness of an arbitrary location in an image using a pixel group of the imaging element, and controls the signal increase rate so that the brightness of that location is appropriate. Adjust depending on the section.

[Example] The present invention will be explained in detail based on the embodiment shown in FIGS. 1 to 3.9 FIG. This is an observation light source consisting of a lamp or the like, and the light emitted from this observation light source 1 reaches a perforated mirror 5 via a condenser lens 2, a photography light source 3 consisting of a strobe tube, and an illumination lens 4. There is. The light incident on the perforated mirror 5 from this illumination optical system is as follows.

The light is reflected by the perforated mirror 5 in the direction of the eye E to be examined, illuminates the fundus of the eye E, is reflected from the fundus, passes through the original optical path, and is further transmitted through the perforated mirror 5 to reach the i-detection optical system. become. An objective lens 6 is arranged between the perforated mirror 5 and the subject's eye E, and behind the perforated mirror 5, a lens 7, a light splitting member 8, and a film camera 9 are sequentially arranged along the optical axis. has been done. On the reflective side of the light splitting member 8, an electronic imaging unit 12 consisting of, for example, a television camera having a lens 10 and an image sensor 11 placed in a conjugate position with the film of a film camera 9 is arranged sequentially along the optical axis. There is. Here, the image sensor 11 is equipped with a transistor for each pixel, for example, and has a so-called non-destructive readout function that allows stored charges to remain almost intact even if they are read out, for example, as described in European Patent Application Publication No. 0132076. A photoelectric conversion element is used. As illustrated in FIG. 2, the electronic image pickup unit 12 is composed of an image pickup element 11°, a charge level detector 13, and a variable amplifier 14.

The output of the electronic imaging section 12 is sent to a control section 15 including a computer.
, a floppy disk, etc., is connected to an analog image recorder 16 having a built-in floppy disk or the like.

The observation light source 1 is a lamp that illuminates the fundus of the eye E during fundus observation, and is conjugate with the photographing light source 3 through the condenser lens 2. The light flux passes through the illumination lens 4, is reflected by the perforated mirror 5, passes through the objective lens 6, and illuminates the fundus of the eye E to be examined. The light reflected from the fundus passes through the objective lens 6, the perforated mirror 5, the lens 7, and the light splitting member 8, and reaches the film surface of the film camera 9, or is reflected by the light splitting member 8, passes through the lens 10, and is sent to the electronic imaging unit. 12 image pickup devices 11 are reached. Note that the light splitting member 8 may be a flip-up mirror when recording film and video alternately.

When the fundus image light flux is incident on the image sensor 11, charges are accumulated on each pixel according to the amount of the incident light. Therefore, non-destructive reading is performed once using the charge level detector 13 to detect the area A.
After checking the charge levels of the pixel groups that are compatible with each other, the control unit 15
Determine the amplification factor at an appropriate level for the variable amplifier 14 by
After that, all pixels are read out again and passed through the variable amplifier 14.
Send it to the analog image recorder 16 as image value number S,
Then, if necessary, the amplification factor of the variable amplifier 14 is changed again to form and record an image video signal. In other words, an image illuminated by the photographing light source 3 is captured on the image sensor 11 having a non-destructive readout function, the charge is read out once, and the variable amplifier 14 is determined, and a video signal is generated from the image sensor 11 and recorded.

Figure 3 shows an example of an image produced by a slit lamp, and in this case, the luminance difference within one screen becomes even thicker.
represents an area on the image sensor 11 used for photometry for proper recording, and this area A can be moved arbitrarily from the outside using a setting input unit (not shown).

Although FIG. 1 shows an embodiment in which the present invention is applied to a fundus camera, it goes without saying that the present invention can be similarly applied to other ophthalmological equipment, such as a slit lamp.

[Effects of the Invention] As explained above, the photographic imaging device according to the present invention determines the exposure based on the amount of light that actually constitutes the image.
Extremely accurate exposure values can be obtained. Furthermore, with a single strobe exposure, it is possible to record while changing the exposure, and there is also the effect that it is possible to record at an optimal level partially within one screen.

[Brief explanation of the drawing]

Drawings 1 to 3 show an embodiment of the ophthalmologic imaging device according to the present invention, in which FIG. 1 is a block diagram of the present invention applied to a fundus camera, and FIG. 2 is a block circuit diagram of an electronic imaging unit. FIG. 3 is an explanatory diagram of an image obtained by a slit lamp, and FIG. 4 is an explanatory diagram of a fundus image. 1 is an observation light source, 3 is a strobe light source, 5 is a perforated mirror, 6 is an objective lens, 8 is a light splitting member 59 is a film camera, 11 is an image pickup device, 12 is an electronic image pickup unit, 13 is a charge level detector, 14 is a variable amplifier, 15 is a control section, 16
is an analog image recording section. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. An imaging unit having a strobe light source and an image sensor composed of a large number of pixels with a non-destructive readout function, and detecting the amount of charge accumulated in a pixel group at an arbitrary location of the image sensor by illumination by the strobe light source. and a control section that controls a signal amplification factor for the output of the imaging section.