JP2003052638A - Ophthalmologic photographing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire and display an image matched with a photographing purpose. SOLUTION: When the gamma of an LUT 34 is set to γ=1 and the gamma of an image pickup means 7 is set to γ=0.45, the gamma becomes 1 as a whole because the gamma of a monitor 23 is almost 2.2. The output from the image pickup means 7 is subjected to A/D conversion and the number of bits is converted by the LUT 34 to be converted to analogue data and this data is outputted to the monitor 23. By this control, a photographer can confirm an image on the monitor and can acquire an image file fitted to diagnostic reading.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic photographing device such as a fundus camera and an ophthalmic filing device used in an ophthalmology clinic.

[0002]

2. Description of the Related Art In recent years, an inexpensive image control means is often used for a personal computer having a video capture board when photographing an ophthalmic image as an electronic image. Furthermore, a system in which an image pickup device such as a television camera and a display device are integrally incorporated in a fundus camera has been announced.

Normally, these systems display a photographed image on a monitor having a γ (gamma) characteristic of 2.2, and mainly aim to confirm the photographed result and interpret the image. Therefore, a television camera or the like for acquiring the image is used. The gamma of the image pickup means is normally set to γ = 0.45 according to the γ characteristic of the display means such as a monitor.

[0004]

However, the above-mentioned conventional example has the following problems. Since the gamma of the TV camera is set to 0.45, the high brightness part of the saved image data has low contrast,
This is an error factor when the brightness measurement and the image processing are performed by the image data.

When the gamma of the television camera is set to 1, when the photographed image is displayed on the monitor, the total gamma including the monitor becomes about 2.2, and the dark portion is sunk. , The image is not suitable for interpretation.

Since the characteristics of the image pickup means used for image acquisition are unclear, errors occur during the luminance measurement and image processing.

Even if a photographed image is obtained, the setting at the time of photographing is unknown, so that it is impossible to correct it.

An object of the present invention is to solve the above-mentioned problems and to provide an inexpensive ophthalmic photographing apparatus capable of acquiring an image suitable for the purpose by acquiring an image for the purpose of image interpretation or an image for the purpose of measurement and image processing. To provide.

Another object of the present invention is to provide an ophthalmologic photographing apparatus capable of properly reading a photographed image on a monitor even when an image for measurement and image processing is photographed.

Still another object of the present invention is to provide an ophthalmologic photographing apparatus capable of appropriately performing measurement and image processing after photographing by adding photographing conditions at the time of image acquisition to tag information of the image.

[0011]

An ophthalmic photographing apparatus according to the present invention for achieving the above object has an image pickup means, an image memory, a digital-analog converter and an image display means,
In an ophthalmologic imaging apparatus that captures a digital image by imaging an eye to be inspected, imaging means control means for changing at least gamma and gain settings of the imaging means, an image data bit converter, and the image data bit converter And a shooting mode selecting means, and changing the gamma of the imaging means and the data set in the image data bit converter according to the shooting mode selected by the shooting mode selecting means. Is characterized by.

Further, the ophthalmologic imaging apparatus according to the present invention has an imaging means, an image memory, a digital-analog converter, and an image display means, and is an ophthalmologic imaging apparatus for photographing a subject's eye to obtain a digital image. Image pickup means control means for changing the setting of means, image data bit converter, control means for changing the data set in the previous image data bit converter, shooting mode selection means, and image file generation means According to the photographing mode selected by the photographing mode selecting means, the gamma of the photographing means and the data set in the image data bit converter are changed, and the image file of the photographing means is associated with the image file generated by the image file generating means. It is characterized in that the set value and the set value of the apparatus are stored.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a configuration diagram of a fundus camera according to the embodiment. In front of the eye E to be inspected, the objective lens 1,
Arranged are a perforated mirror 3 having an aperture stop 2 in the hole portion, taking lenses 4 and 5 which are partially movable for focusing, a movable mirror 6, and an imaging means 7 such as a television camera. Also,
In the direction of incidence of illumination light on the perforated mirror 3, a condenser lens 9, a visible light cut filter 12, a strobe light source 11 that emits a visible light flash, and a ring-shaped light from the observation light source 8 side that emits a visible light such as a halogen lamp. Aperture 1 with aperture
2. Arrange the lens 13. A half mirror 14 and a fixation lamp 15 conjugate with the fundus Er are arranged in the reflection direction of the movable mirror 6, and the relay lens 1 is arranged in the reflection direction of the half mirror 14.
6. A TV camera 17 having a sensitivity in the infrared wavelength region is arranged. The output of the TV camera 17 is connected to the TV monitor 18.

The fixation lamp 15 is composed of an LED array arranged in a dot matrix, or a backlight such as LEDs and a liquid crystal shutter of a dot matrix, and controls dots at arbitrary two-dimensional positions to be transparent or opaque. The fixation target can be presented to the eye E to be examined at any position. An external fixation lamp (not shown) that does not change the fixation position may be used independently.

In this fundus camera, the objective lens 1, the photographing diaphragm 3, and the photographing lenses 4, 5 constitute a fundus observation and photographing optical system, and together with the image pickup means 7, a fundus imaging optical system for photographing the fundus Er of the eye E to be examined. Constitute. In addition, the movable mirror 6,
The half mirror 14, the field lens 16, the television camera 17, and the television monitor 18 constitute an observation optical system for presenting a fundus image to the photographer, and an optical path of the observation light source 8 to the perforated mirror 3 constitutes an illumination optical system.

The output of the image pickup means 7 is connected to the image control means 21 including a frame memory. A control circuit 22, a television monitor 23, an information recording / reproducing means 24, an image acquisition mode selecting means 25, and a patient information inputting means 26 are connected to the image controlling means 21. As the image control means 21, a personal computer having a video capture board, which has been increasing in recent years, can be used. Further, the control circuit 22 is connected to a left / right eye switch 27, a fixation lamp 15, and a light emission control circuit 28 for controlling the strobe light source 11.

At the time of photographing, the photographer first inputs information such as the identification number, name, birth date and sex of the subject from the information input means 26 to the image control means 21. Next, a desired photographing mode is selected from the photographing mode selection means 25 depending on whether the photographing purpose is radiogram interpretation, image measurement or image processing. Then, the photographer positions the subject's eye E in front of the objective lens 1 and performs alignment for photographing the fundus.

When the observation light source 8 is turned on, the light from the observation light source 8 is condensed by the condenser lens 9 and becomes infrared light by the visible light cut filter 10. This observation light passes through the strobe light source 11, the diaphragm 12, and the lens 13, is reflected to the left by the mirror portion of the perforated mirror 3, passes through the objective lens 1, passes through the pupil Ep of the eye E, and illuminates the fundus Er. . Then, the fundus image illuminated with the observation light again has the objective lens 1,
The reflected light is reflected upward by the movable mirror 6 through the photographing diaphragm 3, the photographing lenses 4, 5, and further leftward by the half mirror 14, and passes through the relay lens 16 to reach the television camera 17.

Since the television camera 17 is sensitive to infrared light, it converts the received fundus image into a television signal and outputs it to the television monitor 18. While observing the fundus image on the television monitor 18, the photographer performs precise alignment and focusing between the eye E and the fundus camera, confirms the photographing range, and confirms the photographing light amount and the photographing angle of view as necessary. Make a change.

Then, after confirming that the position adjustment, the focus adjustment, the photographing range, and the like have been performed favorably, a still image is photographed by operating a photographing switch (not shown). The control circuit 22 that detects the input of the photographing switch is
The image control means 2 simultaneously.
The image pickup start signal is output to 1 and the light emission timing signal for the strobe light source 11 from the image control means 21 is awaited.

Now, the light emission timing signal from the strobe light source 11 synchronized with the television camera 17 will be described. When capturing a still image with the light emitted from the strobe light source 11, in order to capture an image with relatively little motion such as a fundus image at the highest possible resolution, it is usually necessary to use a frame accumulation mode of an image sensor such as a CCD. TV camera 1
Drive 7

In the frame accumulation mode, one frame is composed of two fields, a first field and a second field, as shown in FIG. 2. The light accumulation period of each field image is one frame immediately before the output of each field image. It will be a period. That is, 2
The storage periods of the two fields are offset by one field. Therefore, in order to obtain one frame image with one flash emission, the strobe light source 11 must emit light during the accumulation period common to two fields forming one frame. The image control means 21 outputs a strobe light emission command to the control circuit 22 at the timing shown in FIG.

In recent years, a digital camera has been used as an image pickup means in the ophthalmologic region as well as a television camera.
In the case of this digital camera, when the image control means 21 receives a shooting start signal from the control circuit 22, it outputs a light accumulation start signal to the imaging means such as a digital camera. At the same time, a light emission timing signal of the strobe light source 11 is output to the control circuit 22.

When the control circuit 22 receives the light emission timing signal of the strobe light source 11 from the image control means 21, it sends a light emission signal to the strobe light emission control circuit 28 without delay and causes the strobe light source 11 to emit light. The luminous flux emitted from the strobe light source 11 passes through the ring-shaped opening of the diaphragm 12 similarly to the observation light, passes through the lens 13, and is reflected to the left by the mirror portion around the perforated mirror 3 to cause the objective lens 1 to pass through. Transparent eye E
The fundus Er is illuminated from the pupil Ep. The fundus image illuminated in this way passes through the objective lens 1, the photographing diaphragm 3 and the photographing lens 4 again, and forms an image on the image pickup surface of the image pickup means 7. When the image pickup means 7 is a television camera, it becomes a television signal. If the image pickup means 7 is a digital camera, it becomes an image signal and is output to the image control means 21.

The image control means 21 synchronizes the television signal or the image signal for one frame output from the image pickup means 7 with the stroboscopic light emission and fetches it into the frame memory.

FIG. 3 is a functional block diagram of the image control means 21, and FIG. 4 is a flow chart of the operation. Imaging means 7
After receiving the output of the first stage amplifier 31, the A / D converter 3
2 converts analog data to digital data,
The RGB components are stored in the RGB memory 33. Since the image pickup means 7 in recent years has an S / N ratio of 60 db or more, normal A / D conversion is performed with 10 bits. The LUT (look-up table) 34 is used for converting the image data acquired by 10 bits into 8 bits, converting the contrast, and changing the white clip.

Subsequently, control is performed to compress the image according to the compression ratio designated by the compression means 35. Taking JPEG compression as an example, the RGB signals in the RGB memory 33 are converted to YUV.
The signal is converted by the converter 35a and stored in the YUV memory 35b, and then the compression processing 35c is performed to convert the signal into the JPEG image format. At this time, the image data is JPEG
The image format may be converted into an image format such as bmp without being compressed.

Further, the image control means 21 reads the photographing information such as the left and right eye information and treats the information together with the previous patient information as supplementary information associated with the acquired photographed image. The supplementary information can be treated as text information separately from the image data or written in the tag area of the image format. The image control means 21 records the image data via the recording / reproducing means 24 in MO, MD, DVD-RAM, VTR.
A recording medium D capable of storing and holding, such as a tape or a hard disk
Write to or read from.

Photographing information such as left and right eye information can be inputted by the photographer from the information input means 26 to the image control means 21. The image data taken in the RGB memory 33 is converted by the LUT 34 and then written in the display memory 36. The image data written in the display memory 36 is D / A converted by the D / A converter 37 and then output to the television monitor 23 so that the photographer can confirm the image.

In recent years, when photographing with a television camera as a photographing medium, the amount of light that illuminates the eye E to be inspected is sufficiently lower than in conventional film photographing, so that even a non-mydriasis fundus camera can photograph a plurality of images. Become.

Next, the processing method for each image acquisition mode will be described in detail. The apparatus of this embodiment has an image acquisition mode selection means 25 for setting the purpose of acquiring an image. There are roughly two purposes, that is, image interpretation measurement and image processing.

The image displayed on the display means for confirming and reading the photographed image is the gamma (= 2.2) of the monitor 23.
In accordance with the above, the gamma of the image sensor 7 is set to 0.4 as follows.
It is desirable to set it to 5. 1 / 2.2 = 0.45

On the other hand, it is necessary to linearly reproduce the brightness information in the image when the brightness measurement and the image processing are performed. In this case, it is possible to convert the gamma by the LUT 34 after acquiring the image, but an error may occur due to the conversion, so it is preferable to set the gamma of the image pickup unit 7 to 1. However, when an image taken with the gamma set to 1 is displayed on a display means such as a monitor, the dark portion is darkened and the image becomes completely unsuitable for image interpretation. Therefore, it is necessary to convert the gamma of the image data in the image memory with the LUT 34.

The operation when each mode is set by the image acquisition mode selection means 25 will be described below.

(1) Image acquisition for image interpretation When image acquisition for image interpretation is selected by the image acquisition mode selection means 25, the image control means 21 is LU as shown in FIG.
The gamma of T34 is γ = 1, and the gamma of the image pickup unit 7 is γ =
Set to 0.45. Since the gamma of the monitor 23 is approximately 2.2, the gamma becomes 1 as a whole, and the input / output relationship becomes linear.

When the photographing switch is operated, the image control means 21 outputs the output from the image pickup means 7 at the timing described above.
A / D conversion is performed by the A / D converter 32, and the image data is stored in the RGB memory 33. Subsequently, conversion of the number of bits is performed by the LUT 34, conversion is performed by the YUV converter 35a,
The image data is stored in the YUV memory 35b. The image data stored in the YUV memory 35b is compressed by the compression means 35c at a preset compression ratio, and then JPEG is used.
The image format is converted to an image format such as MO and stored in the non-volatile recording medium D such as MO.

The image data stored in the RGB memory 33 is bit-converted by the LUT 34, then written in the display memory 36, converted into analog data by the D / A converter 35, and then output to the monitor 23.

By controlling in this way, the photographer can confirm the image on the monitor 23 and can acquire the image file suitable for the image interpretation.

(2) Image acquisition for measurement and image processing When image acquisition for image interpretation is selected by the image acquisition mode setting means, in step 1 of FIG.
Sets the gamma of the LUT 34 and the gamma of the image pickup means 7 to γ = 1.

When the photographing switch is operated, the output from the image pickup means 7 is output from the A / D converter 32 at the timing described above.
A / D conversion is carried out and the raw image data is stored in the RGB memory 33. Subsequently, the LUT 34 performs conversion of the number of bits, conversion of brightness value and contrast, and conversion of RGB
The signal is converted into a YUV signal by the converter 35a and then Y
The image data is stored in the UV memory 35b. The image data stored in the YUV memory 35b is compressed by a compression unit 35c at a preset compression ratio, and then converted into an image format such as JPEG, and a non-volatile recording medium D such as MO.
Save to.

Subsequently, in step 2, the image control means 21 sets the gamma of the LUT 34 to γ = 0.45, then reads the image data stored in the RGB memory 33, and the LUT 34 reads the gamma, the brightness value, and the contrast. It is converted and written in the display memory 36. The image data written in the display memory 36 is converted into analog data by the D / A converter 37 and output to the monitor 23 to display the acquired image.

As a result, the photographer can acquire the image in the state of γ = 1 and can confirm the image on the monitor 23 with the gamma suitable for the monitor display.
FIG. 7 is a flow chart showing these.

In the above embodiment, the gamma of the image pickup means 7 such as the television camera is set, but the gain and the like may be changed. Further, it is possible to add shooting conditions such as a shooting light amount and a shooting angle of view to the shooting data written in the tag of the image file.

[0044]

As described above, according to the ophthalmologic photographing apparatus according to the first aspect of the present invention, an image suitable for the purpose is obtained depending on whether the image acquisition is for the purpose of image interpretation or the image acquisition for the purposes of measurement and image processing. Can be obtained cheaply.

According to the ophthalmologic image-taking apparatus of the second aspect, even when an image for the purpose of measurement and image processing is taken, the taken image can be properly read by the monitor.

According to the ophthalmologic photographing apparatus according to the third and fourth aspects, by adding the photographing condition at the time of acquiring the image to the tag information of the image, it is possible to appropriately perform the measurement and the image processing after the photographing.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a fundus camera of an embodiment.

FIG. 2 is an explanatory diagram of image capture timing by strobe exposure.

FIG. 3 is a functional block diagram in the image control means.

FIG. 4 is a flowchart of image acquisition control.

FIG. 5 is a gamma correlation diagram of a television camera, a monitor, and an LUT.

FIG. 6 is a gamma correlation diagram of a television camera, a monitor, and an LUT.

FIG. 7 is a control flowchart diagram at the time of shooting.

[Explanation of symbols]

1 Objective lens 4, 5 shooting lens 6 Movable mirror 7 Imaging means 8 Observation light source 11 Strobe light source 15 Fixing light 16 TV camera 21 image control means 22 Control means 23 TV monitor 24 Information recording / reproducing means 25 Image acquisition mode selection means 26 Information input means 33 RGB memory 34 LUT 35 compression means

Claims (4)

[Claims] 1. An ophthalmologic photographing apparatus having an image pickup means, an image memory, a digital-analog converter, and an image display means, which sets a gamma and a gain of at least the image pickup means in an ophthalmic photographing apparatus for photographing a subject's eye to obtain a digital image. Image pickup means control means for changing, image data bit converter, control means for changing data set in the image data bit converter, and photographing mode selection means, and photographing selected by the photographing mode selection means An ophthalmologic photographing apparatus characterized by changing the gamma of the image pickup means and the data set in the image data bit converter according to the mode. 2. An image display memory and a photographed image file generating means, wherein after generating a photographed image file based on the image data converted by the image data bit converter, the image data bit converter and the control are executed. The ophthalmologic imaging apparatus according to claim 1, wherein the setting value of the image data bit converter is converted by the means and displayed on the image display means. 3. An ophthalmologic photographing apparatus having an image pickup means, an image memory, a digital-analog converter, and an image display means and taking a digital image by taking an image of an eye to be inspected, the image pickup means control changing the setting of the image pickup means. Means, an image data bit converter, a control means for changing the data set in the previous image data bit converter, a shooting mode selection means, and an image file generation means, and the selection is made by the shooting mode selection means. According to the photographing mode, the gamma of the image pickup means and the data set in the image data bit converter are changed, and the set value of the image pickup means and the set value of the apparatus are associated with the image file generated by the image file generation means. An ophthalmologic imaging device characterized by storing. 4. The ophthalmic photographing apparatus according to claim 3, wherein the set values of the image pickup unit are gamma and gain, and the set value of the apparatus is a photographing light amount.