JPH01149685A - Tv camera device with solid-state image pickup element - Google Patents

Abstract

PURPOSE:To prevent the solid-state image pickup element of a TV camera device from being affected by deterioration in S/N of an AGC circuit caused by amplification of the circuit by performing the readout of the image pickup element in the vertical direction at a period of >=2V. CONSTITUTION:Signals which are thinned out at every 1V and have a period of 2V are produced from vertical readout signals by means of a V-processing circuit 2 and the signals are used for reading out signals from the solid-state image pickup element 4. When the signals are read out at the period of 2V, the image pickup element 4 can make electric charge accumulation for a time which is double an ordinary time and can obtain more signal levels even at a low-illumination place. Therefore, video signals for image processing can be obtained at high sensitivity even in a low-illumination state even if no AGC circuit is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a TV camera device using a solid-state image sensor.

[Conventional technology]

A TV camera using a conventional solid-state image sensor has a V driver 11 that generates a vertical readout signal, as shown in the block diagram of a TV camera using a conventional solid-state image sensor in FIG.
An H driver 3 that generates a horizontal clock, a solid-state imaging device 4, and an amplifier 5 and A that amplify the output from the solid-state imaging device 4.
GC circuit 7, A L that controls the lens with aperture
It is composed of a C circuit 8, a process circuit 6 that performs gamma correction, etc., and an aperture 9 that adjusts the amount of light incident on the solid-state image sensor 4.

In the timing diagram of the video signal and vertical readout signal of a conventional TV camera shown in FIG. The signal is output from the amplifier No. 5 and amplified by the amplifier No. 5. When the illuminance of the object is low and the output signal of the solid-state imaging element 4 is small, the AGC changes the gain and amplifies it, and at the same time the ALC circuit 8 closes the aperture 9 to obtain the optimum signal level. Conversely, when the illumination is high, the ALC circuit 8 closes the aperture 9 and changes the signal level.

The output from the AGC circuit 7 is subjected to gamma correction, a synchronization signal, blanking, etc., and becomes the final VIDEO signal.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional technology, when the output of the solid-state image sensor 4 is small in low illuminance, the signal is amplified by the AGC circuit 7, noise in the signal is also amplified, and the S/N deteriorates. Even if image processing such as A/D conversion is performed, accurate data cannot be obtained. Further, if the AGC circuit 7 is not provided, there is a problem that the sensitivity of the TV camera is reduced and the level of the video signal becomes low.The present invention is intended to solve this problem. The purpose is to provide a TV camera in which the video signal for image processing has good sensitivity even in low illuminance even without the AGC circuit 7.

[Means for solving problems]

A TV camera device using the solid-state image sensor of the present invention converts an optical image into a video signal and outputs it, and includes a solid-state image sensor such as a CCD or MOS type, and a V driver ( (vertical readout signal) and H driver (horizontal scanning), ■ V processing circuit that operates the driver's signal cycle, P pump that amplifies the signal output from the solid-state image sensor, and blanking and synchronization for the video signal. It is characterized by comprising a process circuit that performs signal loading, gamma correction, etc.

[Effect]

According to the above configuration of the present invention, the amount of charge accumulated in the solid-state image sensor of the TV camera is increased by changing the period of the vertical readout signal, thereby improving the sensitivity of the TV camera at low illuminance. It is.

〔Example〕

FIG. 1 is a circuit block diagram of a TV camera device using a solid-state image sensor according to an embodiment of the present invention, in which 1 is a V driver that generates a vertical read signal, and 2 is a V process that changes the period of the vertical read signal. The circuit includes an H driver 3 that operates in the horizontal direction, 4 a solid-state image sensor, 5 an amplifier that amplifies the video signal of the solid-state image sensor 4, and 6 a process circuit that adds a synchronization signal and performs gamma correction.

Figure i3 is a timing diagram of the video signal and vertical readout signal of a conventional TV camera, and is the period from the rise of the vertical readout signal to the rise of the next pulse, that is, 1
The charge accumulated in the solid-state image sensor 4 during the length v is output as a video signal. FIG. 4 is a timing diagram of a TV camera video signal and a vertical readout signal in an embodiment of the present invention. This signal is used to read out the signal from the solid-state image sensor 4. When the signal is read out at a cycle of 2V, the solid-state image sensor 4 can accumulate charges for twice as long as the IV-by-IV readout method of the prior art, and a higher signal level can be obtained even in a place with low illumination. If the period of the vertical readout signal is not only 2V but also longer, such as 3V or 4V, the time for accumulating charges in the solid-state image sensor 4 becomes longer, and the sensitivity is further increased.

■The solid-state image sensor 4 outputs a video signal using a vertical readout signal obtained by converting the signal from the driver 1 into a period by the V processing circuit 2 and a horizontal drive signal from the H driver 3, which is amplified by the amplifier 5 and processed by the process circuit 5. A sync signal is added and gamma correction is performed to create a composite VIDEO signal.

However, in the timing diagram of FIG. 4, the signal output from the solid-state image sensor 4 has a vertical readout signal period of 2V.
Therefore, in the final VIDEO signal, the actual video portion is alternately repeated in the following order: no video signal → no video signal → video signal.

When performing image processing, it is necessary to detect the absence of a video signal and perform the processing.

The present invention can be used to improve the sensitivity of the solid-state image sensor 4, whether it is a MOS type device or a COD device, as long as it is a device that requires a signal for scanning in the vertical direction.

〔Effect of the invention〕

As described above, according to the invention, by reading out the vertical direction of the solid-state image sensor at a cycle of 2V or more, it is possible to lengthen the charge accumulation time of the solid-state image sensor and increase the signal amount even in low illuminance. is possible, and the S/N is reduced by the amplification of the AGC circuit.
It has the advantage that it is suitable for use as a camera for image processing without suffering from any deterioration in image quality.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing an embodiment of a TV camera using the solid-state image sensor of the present invention. FIG. 2 is a circuit block diagram of a TV camera using a conventional solid-state image sensor. FIG. 3 is a timing diagram of the video signal and vertical readout signal of a conventional TV camera. FIG. 4 is a timing diagram of the video signal and vertical readout signal of the TV camera of the present invention. 1...V driver (vertical) 2...V processing circuit 3...H driver (horizontal) 4...solid-state image sensor 5...amplifier 6...process circuit 7...AGC circuit 8 ...ALC circuit 9...Aperture or more Drawing cleaning G (no changes to the internal nature) Figure 3 Figure 4 Procedure amendment (method) Relationship with the case of the applicant Applicant 2-4-1 Nishi-Shinjuku, Shinjuku-ku, Tokyo (236) Representative Director of Seiko Epson Corporation
Tsuneya Nakamura 4, Agent Address: 2-6-21 Kyobashi, Chuo-ku, Tokyo 104 As shown in the attached sheet (no changes to the content)

Claims (1)

[Claims] a) A TV camera device that converts an optical image into a video signal and outputs the video signal, b) a solid-state image sensor such as a CCD or MOS type, and c) a V driver (vertical) that drives the solid-state image sensor. read signal)
and an H driver (horizontal scanning), d) a V processing circuit that controls the signal period of the V driver, e) an amplifier that amplifies the signal output from the solid-state image sensor, and f) a block for the above signal. A TV camera device using a solid-state image pickup device, characterized by comprising a process circuit that performs ranking, synchronization signal loading, gamma correction, etc.