JPH0512904B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 3-1 Technical Field This invention relates to a still image photographing device using a solid-state photographing element.

3-2 Prior Art Conventionally, in medical examination using an endoscope, not only observation with the naked eye but also photography is performed for comparative observation. In particular, the angle of the stomach is prone to cancer and is often photographed. recent years,
Instead of optical photography using silver halide film, still images are recorded electronically using electronic cameras using solid-state imaging devices such as CCDs.
Although such a still image photographing device has various advantages such as not requiring a developing process, it has a drawback that the dynamic range regarding brightness is narrow. Therefore, the interior of the body cavity, such as the angle of the stomach, has severe irregularities, so that the concave parts are photographed too dark and the convex parts are too bright, making it impossible to diagnose these irregularities. In addition, there is a lot of water in the body cavity, and the light from the light source may be reflected on the water surface. In this case, halation occurs on the screen and diagnosis cannot be performed. If shooting fails in this way,
In order to make an accurate diagnosis, it is necessary to reinsert the endoscope into the patient and take photographs, but this has the disadvantage of causing pain to the patient and increasing the amount of time and effort required by the doctor.

3-3 Purpose An object of the present invention is to provide a still image photographing device capable of photographing still images without failure.

3-4 Overview According to the still image photographing device of the present invention, at least two still images are continuously photographed by changing the amount of light incident on the solid-state photographing element upon a single photographing start instruction.

3-5 Embodiment Hereinafter, an embodiment of the still image photographing device according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration when the present invention is applied to an endoscope. Light from a lamp 12 in a light source unit 10 is incident on a light guide 20 of an endoscope 18 via a condensing mirror 14 and a condensing lens 16. An image inside the body cavity is formed by an objective lens 22, transmitted through an image guide 24, and entered into an electronic camera 26 connected to an eyepiece of an endoscope 18. The optical image incident on the electronic camera 26 is transmitted through a photographing lens 28 and an aperture 30 to a solid-state photographing element 3 consisting of a CCD.
2. The output of a control signal generator 36 that generates various control signals in response to depression of a shooting start button 34 provided on the outside of the electronic camera 26 controls the operation of the actuator 38 that controls the aperture value and the solid-state image sensor 32. It is supplied to a driver 40 which outputs clock pulses. The output of the control signal generator 36 is also supplied to the lamp 12 of the light source unit 10 via the endoscope 18. The image signal output from the solid-state image sensor 32 is supplied to a magnetic disk memory 42.

The operation of this embodiment will be explained with reference to the time charts shown in FIGS. 2a to 2d. Control signal generator 36 provides control signals shown in FIGS. 2b, c, and d to lamp 12, actuator 38, and driver 40, respectively. Before starting photography, the lamp 12 emits light with a small amount of light. When an instruction to start photographing is given as shown in FIG. 2a, the level of the control signal to the lamp 12 is increased as shown in FIG. 2b, and the amount of light emitted from the lamp 12 increases accordingly. In synchronization with the start of photography, the level of the control signal to the actuator 38 becomes the first level A as shown in FIG.
As a result, the aperture value of the aperture 30 is set to the first value. When photographing is started, the control signal generator 10 supplies a control signal to the driver 40 to set the solid-state image sensor 32 first in the storage mode and then in the readout mode, as shown in FIG. 2d. As a result, one still image is photographed at the first aperture value, and the image signal read from the solid-state image sensor 32 is recorded in the magnetic disk memory 42. When the reading of the first image signal is completed, the control signal generator 36 supplies a second level B signal to the actuator 38 as shown in FIG. 2c, and sets the aperture value of the aperture 30 to the first value. is set to a different second value.
In this state, the control signal generator 36 sends a signal to the solid-state image sensor 32 to the driver 40, as shown in FIG.
A control signal is provided to set the device first in storage mode and then in readout mode. As a result, one still image is taken even at the second aperture value, and two still images are taken by changing the amount of light incident on the solid-state image sensor 32.

As described above, according to this embodiment, two still images are taken consecutively at different aperture values in response to a single shooting start instruction. Therefore, even if the subject is too bright or too dark, at least one image will be taken correctly, and no failure will occur. This is particularly effective in cases such as endoscopic photography, where the brightness range of the subject is wide and it is difficult to retake the image. Furthermore, since two images are automatically photographed with a single photographing start instruction, operability is good.

Next, another embodiment of the still image photographing device according to the present invention will be described. The structure of the second embodiment is the same as that of the first embodiment shown in FIG. 1, and only its operation will be explained with reference to the time charts shown in FIGS. 3a to 3d. When an instruction to start photographing is given (FIG. 3a), the control signal to the lamp 12 is set to the first level C, as shown in FIG. 3b, and the amount of light emitted from the lamp 12 is set to the first large amount of light. In the second embodiment, as shown in FIG. 3c,
Since the control signal to actuator 38 is constant, the aperture value of aperture 30 is constant. lamp 12
When the amount of light emitted is the first, the control signal generator 36 controls the driver 40 to take a first still image as shown in FIG. 3d. When this first photograph is completed, the control signal generator 36 sets the control signal to the lamp 12 to the second level D as shown in FIG. 3b.
The amount of light emitted from the lamp 12 is set to a second large amount of light different from the first large amount of light. When the lamp 12 emits the second amount of light, the control signal generator 36 controls the driver 40 to take a second still image as shown in FIG. 3d.

In this way, in the second embodiment, the aperture 30
Although the aperture value is constant, by changing the amount of light emitted from the lamp 12 in the light source unit 10, the amount of light incident on the solid-state photographing element 32 is changed, and two still images are continuously taken. With this, as in the first embodiment, photographing can be performed without failure.

Next, the operation of the third embodiment will be explained with reference to the time charts shown in FIGS. 4a to 4d. The configuration of the third embodiment is also the same as that shown in FIG. In the third embodiment, the control signals supplied to the lamp 12 and actuator 38 are set to a predetermined level in response to an instruction to start photographing (FIG. 4a). Unlike the above-described embodiment, this level remains constant during the shooting of the two still images. As shown in FIG. 4d, the control signal generator 36 controls the solid-state image sensor 32 through the driver 40 to store and read out the first image, and to
Set the storage/readout mode for the first image in sequence. The readout period is unique to the solid-state image sensor 32, and is the same for the first and second images. but,
The storage period is the same as exposure in general photography, and is variable depending on the brightness of the subject. In this embodiment, the accumulation periods for the first and second shots are different.

In this way, according to the third embodiment, the amount of light incident on the solid-state imaging device is changed by changing the storage time of the solid-state imaging device. This produces the same effect as the embodiment described above.

In the second embodiment, the amount of light emitted from the lamp 12 is changed by the control signal, but it is also possible to provide separate lamps with different amounts of light emitted and switch the light to the light guide using a mirror or the like. Alternatively, a discharge tube may be used as the light source lamp, and the discharge light may be emitted by capacitors having different capacities. The configuration of the light source unit 10 in this case is shown in FIG. One end of capacitors 52 and 54 having different capacities are connected to one end of the discharge tube 50, and the other ends of the capacitors 52 and 54 are connected to the other end of the discharge tube 50 via a changeover switch 56. The trigger signal to the discharge tube 50 and the switching control signal to the switch 56 are provided by a control signal generator (not shown in FIG. 5) within the electronic camera. Since the amount of light emitted by the discharge tube 50 depends on the discharge current, by switching the capacitors 52 and 54 with different capacities to light up the discharge tube 50 and performing two imaging operations, solid-state imaging can be performed in the same manner as in the above embodiment. Two still images can be taken by changing the amount of light incident on the element.

This invention is not limited to the embodiments described above, and can be modified in various ways. For example, the number of consecutive shots taken in one shooting start command operation is not limited to two, but three.
It may be more than one. Further, although the solid-state image sensor performs storage and readout separately, the storage for the second image may be performed during the readout period for the first image. Changing the amount of light incident on the solid-state image sensor is not limited to the above-mentioned means. Furthermore, it goes without saying that the present invention can be applied to an endoscope having a solid-state image sensor at its tip.

3-6 Effects of the Invention According to the present invention, at least two still images of the same subject can be continuously photographed by changing the amount of light incident on the solid-state image sensor with a single photographing start instruction operation. A still image capture device is provided. Therefore, even objects with large differences in brightness and darkness can be photographed without failure.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the configuration of a first embodiment of a still image photographing device according to the present invention, Figs. 2 a to d are time charts showing the operation of the first embodiment, and Figs. 3 a to d
is a time chart showing the operation of the second embodiment;
Figures a to d are time charts showing the operation of the third embodiment, and Figure 5 is a diagram showing the configuration of a modified example of the invention. 12...Lamp, 20...Light guide, 22
...Image guide, 30...Aperture, 32...Solid-state image sensor, 34...Release button, 36...Control signal generator.

Claims (1)

[Scope of Claims] 1. A light source device that generates illumination light that illuminates a body cavity of a subject, an endoscope that obtains an image of the subject illuminated by the light source device, and an image obtained by the endoscope. a photographing means for photographing a still image of the subject; a recording means for recording the still image photographed by the photographing means; A still image photographing device comprising: a control means for causing a plurality of photographs to be taken by means of the light source device and for changing the amount of illumination light generated from the light source device for each photographing time.