JPH0474914B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention, when performing strobe photography of the inside of a body cavity with an endoscope, completes the strobe light emission duration during one frame or one field scanning period, and utilizes sunlight from the strobe light. This relates to a control circuit that measures the

In an endoscope camera that uses a solid-state imaging device such as a CCD or BBC to obtain an image signal of a subject inside a body cavity, for example, if the camera uses a two-field, one-frame scanning method, one field scanning period is It is short at 1/60 sec (approximately 16.7 m sec),
On the other hand, the maximum duration of strobe light emission is several ms to 10 ms, depending on the strobe tube and light emission control circuit.
That's about it. Therefore, if the strobe light emission start time is not set appropriately within one field scanning period,
This strobe light emission duration spans two fields, and there is a problem in that the total amount of light emitted by the strobe cannot be used effectively for one strobe photography.

In view of the above-mentioned points, an object of the present invention is to provide a control circuit that controls the timing of strobe light emission so that the light emission start time of the strobe light is appropriately set and the light emission duration period is completed within one field or one frame scanning period. It provides:

The strobe control circuit for an endoscope device of the present invention includes a release detection circuit that detects the operation of a shutter release button for strobe photography and generates a release detection signal, and a camera that has a built-in solid-state image sensor for one field or one frame. A transfer gate signal detection circuit detects a transfer gate signal generated in each scanning period, and a timing signal for starting strobe photography when receiving the transfer gate signal that arrives for the first time after the release detection signal from the release detection circuit is generated. and a sequence circuit that generates the timing signal, and is characterized in that the longest light emission duration of the strobe ends within one field or one frame scanning period of the solid-state image sensor in which the timing signal is generated. be.

The present invention will be described in detail below with reference to the drawings.

Since the configuration of the endoscope apparatus is known, it will be briefly explained with reference to FIG.

This endoscope device 10 includes an image guide section 12
, an operation section 14 consisting of a shutter release button, etc., a light guide section 16, and a light source device 1.
8 and a camera section 20. First, the mirror 22 inside the light source device 18 is tilted toward the collation lamp 24 side, and the operation section 1 is inserted from one end of the light guide section 16 made of glass fiber, for example.
4 and a light guide optical path provided inside the image guide section 12, the collimation light is emitted from the distal end section 17. On the other hand, when the image guide section 12 is inserted into the body cavity from its distal end 17, an optical path separate from the fiber optical path of the light guide section 16 is formed. For example, through the optical path of the image guide section 12 made of glass fiber, an observed image of the body cavity irradiated with collation light is introduced from the tip section 17 to the camera section 20, where it is converted into an electrical signal by a solid-state image sensor. Then, in order to add a synchronization signal and the like to this signal and extract it as a TV signal, the converted electrical signal is processed by a processing circuit 26, which will be described later, and then observed on a monitor 28.

In the case of photographing with a strobe, the mirror 22 is tilted toward the strobe lamp 30, and the shutter release button 32 is pressed to cause the strobe lamp 30 to emit light at a desired instant, as will be described later. A control circuit 34 for determining the start instant and end instant of the light emission duration of this strobe light emission.
is provided in the light source device 18.

Next, one embodiment of the strobe control circuit of the present invention will be described with reference to FIGS. 2 and 3.

FIG. 2 is a block diagram of one embodiment of the strobe control circuit of the present invention, and the portion surrounded by broken lines in FIG. 2 shows a specific circuit of the processing circuit 26. First, the release detection circuit 50 detects the operation of the shutter release button 32 of the operation section 14, and supplies this detection signal to the sequence circuit 52. On the other hand, a camera control circuit 54 generates a TV signal by performing processing such as superimposing a synchronization signal on the output signal from the camera section 20, and also functions to scan the solid-state image sensor of the camera section 20.
is provided and its TV signal is supplied to a transfer gate signal detection circuit 56 which indicates the start of a frame or field scan period to obtain a gate output signal. This TV signal is also supplied to the monitor 28 via the terminal 70. This gate output signal is supplied to the above-mentioned sequence circuit 52, and when a match is found between it and the above-mentioned release detection signal, that is, for example, an AND gate (not shown) is used to perform a logical product. Thus, a timing signal is generated.
On the other hand, the release detection signal is transmitted to this sequence circuit 5.
2, it is immediately supplied to the collimation light cutoff circuit 58, thereby deactivating the collation lamp 24 in the light source device 18.

Here, the operation will be explained with reference to the waveform diagram of FIG. 3. For example, a frame start signal, that is, a transfer gate signal 66 is supplied from the transfer gate signal detection circuit 56 to the sequence circuit 52. In this case, the signal sent from the camera control circuit 54 to the detection circuit 56 includes an image signal, but is removed by the detection circuit 56, resulting in a signal containing only the gate signal component as shown at 66. When the release 32 is operated at time t ₁ , it is detected by the release detection circuit 50 and a release detection signal 60 is generated, which is supplied to the sequence circuit 52 .
This release detection signal 60 is transmitted to the illumination light cutoff circuit 58.
is supplied to turn off the collation lamp 24, and is held until the transfer gate signal 66 is generated.
It is supplied together with the transfer gate signal 66 to an AND gate (not shown) to perform a logical product. As a result, the timing signal 62 is output from the sequence circuit 52 at time _t2 , and is supplied to the strobe light emission control circuit 34, so that the strobe tube 30 starts emitting light in a short time.

Generally, the longest flash duration of a strobe is several ms~
m sec, whereas the scanning period of one field is approximately 16.7 m sec (=1/60 sec) (in this case, in the 2-field/1 frame method, the scanning period of one frame is approximately 33 m sec). (=1/30
sec). The operation will be described below assuming that the strobe's longest light emission duration is 10.0 ms. In the present invention, in order to effectively utilize the amount of light emitted by a single strobe, it is necessary to control the strobe light emission so that the longest light emission duration of the strobe light is completed within one field scanning period. That is, approximately (16.7−10.0≒6.7 m sec) from the field start instant _t2 of the transfer gate signal when the timing signal 62 is generated.
The strobe light emission is started within (=Δt).
In other words, the strobe light is controlled to complete its longest light emission duration within one field scanning period in which the timing signal is generated. This is the third
This means that the strobe light emission control circuit 34 controls the time Δt before the start of light emission of the strobe waveform 80 shown in the figure to be 0 to about 6.7 msec.

As described in detail above, according to the present invention, by controlling the timing of strobe light emission,
Since the entire amount of light emitted by the strobe can be contained in one field or one frame scanning period, the strobe light can be emitted at the desired time during observation by displaying the image signal from the camera with a built-in solid-state image sensor on a monitor. This has the advantage that it is possible to effectively utilize the stroboscopic light, achieve good strobe photography in a dark body cavity, and also realize high-speed photography using a strobe.

The present invention is not limited to the embodiments described above, and various modifications may be made.

For example, in the embodiment, one frame signal was obtained by interlacing two fields, but the present invention is not limited to this, and one frame signal (1/30
sec), and in this case it is clear that Δt can be set longer than in the embodiment.

Further, in this example, the collation lamp was turned off before flash photography, but it may be left on. Although the present embodiment shows an example in which the camera section 20 is attached to the operation section 14, the present invention is not limited to this, and may also be applied to an endoscope in which the camera section 20 is incorporated in the distal end section 17, for example. Of course, it is possible to implement it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the entire system in which the control circuit of the present invention is incorporated into an endoscope device, and FIG.
The figure is a block diagram of one embodiment of the control circuit of the present invention, and FIG. 3 is a waveform diagram showing waveforms at various parts of FIG. 2. 10...Endoscope device, 18...Light source device, 20
... Camera section, 26 ... Processing circuit, 32 ... Shutter release, 50 ... Release detection circuit, 52
...Sequence circuit, 54...Camera control circuit,
56...Transfer gate signal detection circuit, 58
. . . Collation light cutoff circuit, 80 . . . Strobe light emission waveform.

Claims (1)

[Claims] 1. In a strobe control circuit for an endoscope device that displays image signals from a camera with a built-in solid-state image sensor on a monitor and performs photography with a strobe at a desired time during observation, the shutter release button for strobe photography is activated. a release detection circuit that detects and generates a release detection signal; a transfer gate signal detection circuit that detects a transfer gate signal generated every one field or one frame scanning period from a camera incorporating a solid-state image sensor; a sequence circuit that generates a timing signal for starting strobe photography when receiving the transfer gate signal that arrives for the first time after the release detection signal is generated from the circuit;
A strobe control circuit for an endoscope, characterized in that the longest light emission duration of a strobe ends within a field or one frame scanning period.