JP2797515B2 - Solid-state imaging tv camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state imaging television camera for image processing that captures an image by emitting a strobe light.

[Prior Art] A conventional image processing system using a camera of this type will be described with reference to FIGS. 5 and 6. FIG. A strobe light emission timing pulse (hereinafter simply referred to as a strobe pulse) ST (FIG. 6A) is supplied from the strobe timing generator 1 to the strobe 2 and the image processing device 3. The strobe 2 emits light immediately upon receiving the strobe pulse ST, and the signal electrification of a brightly illuminated subject is performed by a CCD (Charge Coupled Device).
e; charge-coupled device) accumulated in the light-receiving device (photodiode) of the television camera 4.

In the timing circuit of the television camera 4, the transfer gate pulse TG is transmitted at a timing near the trailing edge of the vertical drive signal (also referred to as a vertical synchronization signal) VD (FIG. 6B).
(FIG. 6C) is generated and supplied to the transfer gate of the CCD image sensor to open the gate. If a field strobe pulse ST is generated as F _1, the transfer gate pulse TG ₂ of the next field F ₂ and its next field F ₃
And by TG _3, it until each odd field or even field corresponding amount of accumulated have signal charge is transferred all at once to the vertical transfer registers to the light receiving element. Between F ₂ and F ₃ fields from the television camera 4, the video signal V ₂ and V ₃ (either odd field, the other is a video signal of the even field) is supplied to the image processing apparatus 3. In other fields, even if the transfer gate is opened, there is no stroboscopic light emission, so the state is dark (darkness), and the signal charge stored in the light receiving element is negligible compared to the case with strobe light emission. Therefore, the video signal V becomes zero level except for the synchronization signal.

The image processing device 3 synchronizes with the leading edge of the first and second vertical synchronizing signals VD ₂ and VD ₃ (synchronized and separated by the sync separation circuit) starting after receiving the strobe pulse ST, and outputs the video signal V ₂ and V ₃ is stored in the image memory device.

[Problem to be Solved by the Invention] In a conventional imaging system, the strobe pulse ST of the strobe timing generator 1 is changed as shown in FIG.
Considering the case where the signal exists within the duration of the vertical synchronization signal VD of the television camera 4, the image processing apparatus 3 always receives the strobe pulse ST and then starts the first and second vertical synchronization signals VD ₂ , VD. ₃ in synchronism with the leading edge of, the operative to store a video signal V, the video signal of the F ₁ field V ₁
Is not stored and the signal is lost.

When the strobe pulse ST is generated at substantially the same timing as the transfer gate pulse TG as shown in FIG. 8, the video signals V ₁ and V ₂ of the F ₁ and F ₂ fields are output from the television camera 4. or is output, F _2, F ₃ field of the video signal
V ₂ and V ₃ are output and become unstable. As described above, the image processing device 3 stores the video signal in synchronization with the leading edges of the synchronization signals VD ₂ and VD _3. Therefore, when the video signals V ₁ and V ₂ are output from the TV camera 4, disadvantage that V ₁ is not stored as in the case of Figure 7 occurs.

The present invention adds a simple circuit to a TV camera,
The purpose is to eliminate such inconveniences.

[Means for Solving the Problems] At a timing near the trailing edge of the vertical synchronization signal, a transfer gate pulse to be supplied to the solid-state imaging device exists, and a strobe light is emitted to output a bright video signal of the subject. In the solid-state imaging television camera, according to the present invention, when the timing pulse for emitting the strobe light exists within the duration of the vertical synchronization signal or the transfer gate pulse near the trailing edge, the transfer gate pulse is transmitted to the solid-state imaging device. Is removed from the transfer gate pulse supplied to.

"Embodiment" An embodiment of the present invention is shown in FIG. 1 by attaching the same reference numerals to parts corresponding to FIG. Unlike the related art, the strobe pulse ST of the strobe timing generator 1 is also input to the CCD television camera 4.

In the conventional imaging system shown in FIG. 5, the inconvenience occurs in the case of FIG. 7 in which the strobe pulse ST is generated within the duration of the vertical synchronizing signal VD because the video signals V ₁ and V ₂ from the video camera 4 are generated. This is because the video signals V ₂ and V ₃ are stored in the image processing device 3 while being output. The same applies to the case of FIG. 8 in which the strobe pulse ST is generated at substantially the same timing as the transfer gate pulse TG. Therefore, in the present invention, the image processing apparatus 3 outputs the video signals V ₂ and V ₃ (for one frame) from the TV camera 4 and does not output V ₁ in both cases of FIGS. 7 and 8. To match. Therefore, when the strobe pulse ST exists at a special timing as shown in FIGS.
From the transfer gate pulse TG supplied to the image pickup device is to remove the transfer gate pulse TG ₁ in F ₁ field. The transfer gate pulse correction circuit 11 in FIG. 1 is a circuit for that purpose.

A strobe pulse ST (FIG. 2A) is input from the strobe timing generator 1 to the first time constant circuit 12 via the input terminal IN of the television camera 4. The first time constant circuit 12 is composed of, for example, a monostable multivibrator, and its output
ST ', as shown in FIG. 2 D, immediately falling when ST rises, the transfer gate pulse TG ₁ is an elevational amounting pulse after up standing. Therefore, the time length of the pulse ST 'is slightly larger than the sum of the time length of the vertical synchronizing signal VD and the time length of the transfer gate pulse TG, and is usually about several H to 20H.

The vertical synchronization signal VD used in the television camera 4 is applied to a second time constant circuit (for example, a monostable multivibrator) 13. The output VD '(FIG. 2E) falls simultaneously with the fall of VD, and rises after the transfer gate pulse TG rises. Therefore, the length of VD 'is almost the same as the time of ST'.

When the outputs ST 'and VD' of the first and second time constant circuits 12 and 13 are applied to the NOR gate 14, the output INH (FIG. 2F) becomes S
The pulse becomes a high level while both T 'and VD' are at a low level. When the output INH of the NOR gate 14 and the transfer gate pulse TG used in the television camera 4 are applied to the OR gate 15, the output TG '(FIG. 2G) becomes one of the transfer gate pulses TG. TG ₁ is masked by the INH pulse, resulting in a lost pulse train. Therefore, in the CCD image sensor, the signal charge accumulated in the light receiving element is TG ₁
In the timing is not transferred to the vertical transfer register is transferred at the timing of TG ₂ and TG ₃ fields of and F ₃ F _2. As a result, the video signals V ₂ and V ₃ in the F ₂ and F ₃ fields (one of which is an odd field,
The other is an even field signal) (FIG. 2H).

The transfer gate pulse correction circuit 11 is constituted by the first and second time constant circuits 12 and 13, the NOR gate 14 and the OR gate 15.

FIG. 3 shows a time chart when the strobe pulse ST is generated at substantially the same timing as the transfer gate pulse TG. Video signals V ₂ and V ₃ are output as in the case of FIG. The operation of each unit is the same as that in FIG. 2 and will not be described.

The time chart of the general case the strobe pulse ST is generated in the middle of the F ₁ field shown in Figure 4. The outputs ST '(FIG. 4D) of the first and second time constant circuits 12, 13 and VD'
(FIG. 4E) does not become a low register at the same time, so that the output INH of the NOR gate 14 is always at a low level, and the transfer gate pulse TG is not masked by INH but becomes the output TG 'of the OR gate 15 as it is. The operation of each unit is the same as that in FIG. 2 and will not be described.

The transfer gate pulse correction circuit 11 may have a different configuration from the circuit of FIG. In the description so far, the image signals V ₂ , V ₃ are synchronized with the rising edges of the first and second vertical synchronization signals VD ₂ , VD ₃ which start after the image processing device 3 receives the strobe pulse ST. It shall store, to match the operation of the image processing apparatus, the transfer gate pulse correction circuit 11, as required, and to mask the transfer gate pulse TG ₁ of F ₁ field. However, operation of the image processing apparatus 3, when (the m arbitrary integer) F _m and F _{m + 1} field method for storing the video signal of the transfer gate pulse correction circuit 11 so as to match to the , together with masking the transfer gate pulse TG ₁ in the same manner as described above, TG ₂ ~
Try to mask TG _m-1 . For this purpose, for example, a monostable multivibrator is inserted between the NOR gate 14 and the OR gate 15 in FIG.
2) It may be extended by F time (F is vertical time).

In the description so far, the vertical synchronizing signal VD is superimposed on the video signal V and transmitted to the image processing apparatus 3. However, a dedicated line may be provided and transmitted separately from the video signal V.

According to the present invention, in a system that emits a strobe and processes an image captured by a CCD television camera, a timing pulse ST that causes the strobe to emit light includes a vertical synchronization signal VD of the CCD television camera and a trailing edge of the trailing edge. In special cases such as being within the duration of the nearby transfer gate pulse TG, the transfer gate pulse is deleted from the transfer gate pulse TG supplied to the CCD image sensor and accumulated in the photodiode of the CCD image sensor until then. The transferred signal charges are not transferred.

Conventionally, this signal charge was transferred and output as a video signal from a television camera.However, in the image processing apparatus, when the strobe pulse ST is at the above special timing, the video signal immediately after that is not stored. However, there is a disadvantage that the video signal is eventually lost. However, according to the present invention, such a disadvantage does not occur.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a time chart in the case where the strobe pulse ST exists within the duration of the vertical synchronizing signal VD in FIG. 1, and FIG. Time chart when the strobe pulse ST exists at substantially the same timing as the transfer gate pulse TG,
FIG. 4 is a time chart when a strobe pulse ST is present in the middle of an adjacent vertical synchronizing signal VD in FIG. 1, and FIG. 5 is a conventional method in which a strobe light is emitted and an image is processed by photographing with a CCD television camera. Block diagram of the system,
FIG. 6 is a time chart in the case where the strobe pulse ST exists in the middle of the adjacent vertical synchronizing signal VD in FIG. 5,
FIG. 7 is a time chart when the strobe pulse ST is present within the duration of the vertical synchronization signal VD in FIG. 5,
FIG. 8 is a time chart in the case where the strobe pulse ST exists at substantially the same timing as the transfer gate pulse TG in FIG.

Claims (1)

(57) [Claims] 1. A solid-state imaging television camera in which a transfer gate pulse to be supplied to a solid-state imaging device exists at a timing near a trailing edge of a vertical synchronization signal, and a strobe is emitted to output a bright video signal of a subject. In the above, when the timing pulse for emitting the strobe light exists within the duration of the vertical synchronization signal or the transfer gate pulse near the trailing edge, the transfer gate pulse is deleted from the transfer gate pulse supplied to the solid-state imaging device. A solid-state imaging television camera.