JP3298699B2 - Electronic shutter drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic shutter driving device,
In particular, the present invention relates to electronic shutter control of an imaging apparatus using a solid-state imaging device such as an electronic endoscope and various cameras.

[0002]

2. Description of the Related Art An electronic shutter driving device is used for various cameras such as an electronic endoscope and a television camera for observing a narrow place.
The electronic shutter control is performed for (ge Coupled Device). That is, in the CCD, an image signal is formed by reading out the electric charge accumulated for each pixel, and the electronic shutter is executed by controlling the accumulation time of the electric charge constituting the pixel signal.

The electronic shutter function can be operated, for example, in accordance with the state of movement. If there is movement, if the electronic shutter speed is controlled to be high, the effect of the afterimage effect due to movement (image blur) is avoided. An image will be obtained. In addition, an electronic shutter function can be used to maintain a white balance, adjust a color temperature, set a desired display color, and the like.

[0004]

However, in the above-mentioned conventional electronic shutter driving device, the driving of the electronic shutter is always performed over the entire image pickup area of the CCD, and the electronic shutter is also used for unnecessary portions (regions). There is a problem of being executed. For example, in a case where the electronic shutter function is used according to the movement, an image having a moving portion becomes an image which is easy to see due to the electronic shutter operation, but a portion having no movement becomes a discontinuous image on the contrary, and the image is stable. In addition, when the electronic shutter operation is performed, the S / N ratio of a signal is deteriorated, so that there is a problem that image quality is deteriorated. Therefore, if the electronic shutter function can be limited to a necessary part, a convenient device can be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to limit the electronic shutter operation to a part of an image pickup area, and to provide an electronic shutter driving device in which the electronic shutter function is effectively used. Is to provide.

[0006]

According to a first aspect of the present invention, there is provided an electronic shutter driving device for driving an electronic shutter of a solid-state imaging device, wherein an imaging region of the solid-state imaging device is divided. The electronic shutter operation is performed only on an area selected from the divided areas.

According to a second aspect of the present invention, a detection circuit is provided for detecting whether or not to execute an electronic shutter operation for each of the divided areas, and the electronic shutter operation is performed based on an output of the detection circuit. It is characterized by executing. Furthermore,
According to a third aspect of the invention, when a predetermined detection is performed in a plurality of regions by the detection circuit, the electronic shutter operation is performed for either the entire region or the center region.

[0008]

According to the above arrangement, the imaging area of the solid-state imaging device is divided into, for example, three in the vertical direction, two in the central part and the outer peripheral part, or in a matrix. Then, an electronic shutter operation is performed on one or more of the divided regions (including the entire region). Although the execution of the electronic shutter operation can be specified in advance, it is preferable that the detection be performed by a detection circuit. For example, when detecting a motion, a motion state is detected for each area, and an electronic shutter operation is performed for a motion area.
At this time, when a plurality of moving areas are detected, the electronic shutter operation can be performed for either the entire area or the center area, thereby improving control efficiency,
Also, a clear and easy-to-view image is formed.

[0009]

FIG. 1 shows the configuration of an image pickup apparatus using an electronic shutter driving device according to an embodiment, and this device can be applied to an electronic endoscope and the like. In the figure, a CCD 10, which is a solid-state image sensor, is arranged via an optical system member, and an image processing circuit 12 is connected to the CCD 10 via an amplifier 11. In the image processing circuit 12, gamma correction, white balance processing, and the like are performed, and in an electronic endoscope, a video signal is stored in a memory. A TV monitor (or display) 13 is connected to the image processing circuit 12, and an image of an observation target (subject) is displayed on the TV monitor 13.

FIG. 2 shows the internal structure of the CCD 10. The CCD 10 includes an image pickup section 17 in which columns of pixel cells 15 composed of photodiodes and the like and transfer lines 16 are arranged alternately, and The storage unit 18 stores the electric charge detected at 15. In addition, a drain unit 19 for sweeping out electric charges by a sweep pulse is provided above the imaging unit 17, a transfer gate 20 is provided between the imaging unit 17 and the storage unit 18, and a read register 21 is provided below the storage unit 18. In the embodiment, such an image pickup section 17 is divided into three areas D1, D2, and D3, and the electronic shutters are separately driven for these areas D1, D2, and D3. That is, a control voltage pulse (sweep pulse, readout pulse, etc.) for the electronic shutter operation is applied to the divided areas D1, D2, D3 when the electronic shutter is driven, and a predetermined voltage is applied when the electronic shutter is not driven. A control voltage pulse is provided.

In FIG. 1, after the amplifier 11,
An area designating gate circuit 22 for extracting a video signal in the divided areas D1, D2, D3 is connected to the area designating gate circuit 22, and in the embodiment, a motion detecting circuit 23A,
23B and 23C are connected. Therefore, in the motion detection circuits 23A, 23B, and 23C, the divided areas D1, D
The motion state is detected for each of 2 and D3. For example, a motion state of a plurality of stages is detected by detecting a change in a luminance signal or the like. Then, the motion detection circuits 23A, 23A
An electronic shutter command circuit 24 is connected to 3B and 23C, and a CCD driving circuit 25 for driving the CCD 10 is connected to the electronic shutter command circuit 24.
Outputs an area designation signal to the CCD drive circuit 25.
Further, a timing pulse generation circuit 26 is provided, and the timing pulse generation circuit 26
2. Necessary timing pulses are supplied to the area designation gate circuit 22, the CCD drive circuit 25, and the like.

That is, the electronic shutter command circuit 24
Based on the detection outputs from the motion detection circuits 23A, 23B, and 23C, an area in which the electronic shutter operation is to be performed is specified, and a control signal for the electronic shutter is formed. Then, the CCD drive circuit 25 supplies a control signal for an electronic shutter to a designated area, and a normal control signal to other areas. The control signal includes a sweep pulse and a read pulse.
By applying a different DC voltage to each of the 0 divided areas D1, D2, D3 and changing the phase of the control pulse, the electronic shutter can be executed. Therefore, as described below,
The electronic shutter operation is achieved by sweeping out the charge accumulated in the CCD 10 at a time controlled by a sweeping pulse, and then reading out the accumulated charge.

The embodiment has the above configuration, and its operation will be described below with reference to FIG. When the power is turned on, for example, in an electronic endoscope, observation light is irradiated via a light guide (not shown), and an object to be observed captured by the observation light is imaged on the imaging surface of the CCD 10. Thereby, in the CCD 10, for example, a video signal of one field is formed for each 1/60 second vertical synchronization (VD) signal shown in FIG.
1 and supplied to the image processing circuit 12. The video signal that has undergone necessary processing such as gamma correction in the image processing circuit 12 is output to a TV monitor 13, and an image of the inside of the subject is displayed on the TV monitor 13.

During such image processing, the video signal from the CCD 10 is moved by the area designating gate circuit 22 to the motion detecting circuits 23A, 23A,
23B, 23C, where the object to be observed (subject)
Is detected. When the motion state is detected, a detection signal including the degree of the motion is supplied to the electronic shutter command circuit 24, and the electronic shutter command circuit 24 moves from among the divided areas D1, D2, and D3. Is specified. For example, if there is no movement in the areas D1 and D3 and there is movement in the area D2,
2 is supplied to the CCD drive circuit 25.

Then, in the CCD driving circuit 25, the control voltage pulse Pa shown in FIG. 3B is applied to the areas D1 and D3 of the CCD 10 in the area D1 shown in FIG.
1 and D3, whereby the charges C11, C12, C13,... Accumulated after the control voltage pulse Pa are read (from the read register 21 by the read pulse) as shown in FIG. 3 (C). At the same time, the area D2
3D, the control voltage pulse (sweep pulse) Pb shown in FIG. 3D is applied to the region D of the CCD 10 shown in FIG.
2 and as shown in FIG. 3E, the electric charge C2 accumulated after the control voltage pulse Pb.
1, C22, C23... Are read out. As shown, the accumulation time of the charges C21, C22, C23,... Is controlled by the control voltage pulse Pb.
This means that the electronic shutter operation has been executed by controlling the accumulation time by b.

As described above, in the embodiment, an image on which the electronic shutter operation has been performed only on the area D2 is displayed on the TV monitor 13, and an image on which no electronic shutter operation has been performed is displayed on the other areas D1, D3. Will be. Therefore, in the area D2, an image in which the afterimage effect (image blur) due to the motion is eliminated is displayed, and the areas D1,
With respect to D3, a good image is displayed with a calm image and without a decrease in the S / N ratio.

In this embodiment, when motion is detected in a plurality of areas, for example, when motion is detected in both area D1 and area D2, the electronic shutter operation is performed for all areas D1, D2, and D3. You may do
Thereby, an easy-to-view image can be provided. Further, in the above-described embodiment, the case of detecting the motion state has been described. However, the present invention is not limited to this. For example, detection is performed to match a set favorite color display color, and the electronic shutter operation is performed based on the detected value. It may be executed.

FIG. 4 shows another example of division by the CCD 10. For example, as shown in FIG.
It may be divided into a circular center area D4 and an outer peripheral area D5,
As shown in FIG. 4 (B), it may be divided into a square center area D6 and an outer peripheral area D7, or it may be divided into a matrix like the areas E1 to E9 in FIG. 4 (C). it can. In these cases, the detection for the electronic shutter operation is performed for the same area. In particular, in the case of FIG. 4C, when a plurality of areas are detected, it is preferable to execute the electronic shutter operation for all the areas E1 to E9 or only the central area E5. For example, when motion is detected for the central region E5 and the region E3, the electronic shutter operation can be performed only for the central region E5 having high importance, thereby enabling efficient control and obtaining a screen that is easy to see. Will be done.

Further, the area designation of the electronic shutter operation in such a divided area can be selected and designated by a preset condition or by a switching operation of a switch or the like, without depending on the output of the detection circuit.

[0020]

As described above, according to the first aspect of the present invention, the electronic shutter driving device divides the imaging region of the solid-state imaging device and sets the electronic shutter only in a region selected from the divided regions. Since the operation is performed, the electronic shutter operation can be limited to a necessary part of the imaging area, and the image quality is prevented from being degraded in the area where the electronic shutter operation is not performed. There is an advantage that it can be.

According to the second and third aspects of the present invention, a detection circuit for detecting whether or not to execute an electronic shutter operation for each of the divided areas is provided, and an output of this detection circuit is provided. Since the above-described electronic shutter operation is performed based on the electronic shutter operation, the electronic shutter operation can be performed only in a necessary area according to the state of movement. At this time, if a predetermined detection is performed for a plurality of regions, the electronic shutter operation can be performed efficiently and an easy-to-view image can be obtained by executing the electronic shutter operation for either the entire region or the central region.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an imaging device using an electronic shutter driving device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram showing a structure of a CCD in an embodiment.

FIG. 3 is a waveform chart showing the operation of the embodiment.

FIGS. 4A to 4C are diagrams showing another example of area division in a CCD.

[Explanation of symbols]

 10: CCD, 22: area designation gate circuit, 23A, 23B, 23C: motion detection circuit, 24: electronic shutter command circuit, 25: CCD drive circuit, D1, D2, D3: divided area.

Claims (3)

(57) [Claims] 1. An electronic shutter driving device for driving an electronic shutter of a solid-state imaging device, wherein an imaging region of the solid-state imaging device is divided, and an electronic shutter operation is performed only on a region selected from the divided region. An electronic shutter driving device, characterized in that: A detecting circuit for detecting whether or not to execute an electronic shutter operation for each of the divided areas; and performing the electronic shutter operation based on an output of the detecting circuit. The electronic shutter driving device according to claim 1. 3. An electronic shutter operation according to claim 1, wherein when a predetermined detection is made in a plurality of areas by said detection circuit, an electronic shutter operation is performed for either the entire area or the center area. An electronic shutter driving device as described in the above.