JPH1032747A - Camera apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform suitable signal processing by correcting the timing to drive the image sensor of an image pickup system and a signal processing system based on the length of a cable. SOLUTION: Based on the detected result of a voltage value impressed to a resistor provided in a cable 20, a microcomputer 48 controls a timing generator 35a so as to correct the generation timing of synchronizing signal, SHD pulse and SHP pulse or the like. The timing generator 35a generates the synchronizing signal and a sampling pulse and generates the SHP pulse and SHD pulse whose phase of image pickup signal transmission delay is delayed. A CCD driver 32 generates a driving pulse based on this synchronizing signal and corresponding to this driving pulse, a CCD image sensor 11 is driven. Based on these SHP pulse and SHD pulse, a CDS/AGC circuit 33 performs correlative double sampling processing to the image pickup signal from the CCD image sensor 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera device for supplying an image signal from a camera head to a camera control unit via a cable to perform signal processing, and more particularly to a camera device for automatically performing cable compensation.

[0002]

2. Description of the Related Art At present, there is provided a camera apparatus whose imaging system is as small as a little finger. Such a camera device captures an image of an object using, for example, a 1/4 inch CCD image sensor, and transfers an image signal obtained by the image capture to a camera control unit (CCU: Came: Came) via a cable.
ra Control Unit). In the camera device,
In this CCU, a digital signal processor (D
Digital signal processing such as gamma correction and white balance adjustment is performed based on sampling pulses in a digital signal processor (SP), and the CCD image sensor is driven based on a synchronization signal obtained in the DSP. .

That is, in the above-described camera device, a driving pulse for driving the CCD image sensor is supplied from the CCU to the camera head via a cable, and an image signal obtained by the CCD image sensor is transmitted from the camera head via the cable. Supplied to the CCU. The CCU performs digital signal processing on the supplied image signal, and then outputs the image signal to a monitor device or a recording system.

[0004]

By the way, usually, DS
The timing generator in P converts digital signals such as correlated double sampling processing, A / D conversion, gamma correction and knee processing to a synchronization signal for driving the CCD driver and an image signal obtained by the CCD image sensor. A sampling pulse for performing the processing is generated.

However, in the above camera device, C
A driving pulse for driving the CD image sensor is supplied to the CCD image sensor via a cable, and an imaging signal obtained by the CCD image sensor is transmitted to the CCU via the cable.
, A signal delay occurs. Therefore, a phase shift occurs between the drive timing of the CCD image sensor and the timing of signal processing, and a problem has arisen in which the signal processing system cannot perform appropriate signal processing.

In particular, when correlated double sampling is performed on an image signal obtained by a CCD image sensor, it is not possible to sample and hold at a data level and a precharge level, so that an optimum image signal can be obtained. could not.

The present invention has been made in view of such a problem, and corrects the drive timing of an image sensor and a signal processing system of an imaging system based on the length of a cable to perform appropriate signal processing. It is an object of the present invention to provide a camera device capable of performing such operations.

[0008]

In order to solve the above-mentioned problems, a camera apparatus according to the present invention supplies an image pickup signal from a camera head to a camera control unit via an exchangeable cable to perform signal processing. In the camera apparatus to be applied, the camera head has an image sensor, and the camera control unit performs image sensor driving means for driving the image sensor, cable length detecting means for detecting the length of the cable, and signal processing of the imaging signal. It is characterized by having signal processing means for applying and control means for controlling the timing of driving the image sensor driving means and the signal processing means based on the detection result of the cable length detecting means.

When the camera head and the camera control unit are connected via a cable, the control means controls the image sensor driving means and the signal processing means based on the length of the cable detected by the cable length detecting means. Control the drive timing.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The present invention relates to a camera device that supplies an image pickup signal from a camera head to a camera control unit (CCU) via a cable and performs signal processing.
When attached to the CU, the length of the cable is automatically detected, and the signal processing can be performed by correcting the timing of the sampling pulse based on the detection result.

The camera device according to the present invention has a camera head 10 and a CCU 30 connected to the camera head 10 via a cable 20, for example, as shown in FIG.

The camera head 10 is formed, for example, as small as a little finger. The camera head 10 includes a CCD image sensor 11 that generates an image signal, a preamplifier / buffer circuit 12 that amplifies the image signal, and an operation unit 1.
3 is provided.

The CCD image sensor 11 is, for example, 1 /
It is 4 inches in size. This CCD image sensor 1
1 generates an imaging signal according to imaging light of a subject and supplies the imaging signal to the preamplifier / buffer circuit 12.

The preamplifier / buffer circuit 12 amplifies the image signal supplied from the CCD image sensor 11 to reduce the S / N in order to cope with the case where the cable 20 is extended by replacing the cable 20 as described later. The enhanced and amplified image signal is transmitted to the CCU via the cable 20.
30.

The operation unit 13 can set the size of a color bar area displayed on a screen of a monitor device or the like.
A color bar area can be set for the color bar circuit 44 by performing a setting operation to a predetermined preset value. Therefore, when a predetermined operation is performed, the operation unit 13 supplies an operation signal to a microcomputer (microcomputer) 48 in the CCU 30 described later via the cable 20. Therefore, the microcomputer 48 can control the output period of the color bar signal output from the color bar circuit 44 described later based on the operation signal.

As shown in FIG. 2, one of cable connectors 21 provided at both ends of a cable 20 is fitted to the camera connector 14 of the camera head 10. The other cable connector 21 of the cable 20 is fitted to the CCU connector 31 of the CCU 30. That is, the cable connector 21 provided at both ends of the cable 20 are respectively formed in the same shape, as shown in FIG. 3, each have a resistance R ₂ for detecting the cable length. Therefore, no matter which cable connector 21 is fitted to the CCU 30, the microcomputer 48
The length of 0 can be recognized.

The CCU 30 is supplied with an imaging signal obtained by the camera head 10 via a cable 20. A CCU connector 31 to which the imaging signal from the camera head 10 is supplied, and a CCD image sensor. A CCD driver 32 for driving the sensor 11, and a correlated double sampling / automatic gain control (C
DS / AGC: Correlated Double sampling / Automatic
Gain control) circuit 33, an analog / digital (A / D) converter 34, a digital signal processing circuit (DSP: Digital Signal Processor) 35, and an electronic zoom circuit 36 for enlarging a specific portion of an image by signal processing.
And a video signal output circuit 37 as an encoder, and an input / output connector 38 connected to a cable from a monitor device or a personal computer.

An image signal supplied to the CCU 30 via the cable 20 is transmitted to the CDS /
It is supplied to the AGC circuit 33. Also, CCD driver 3
The drive pulse from the device 2 drives the CCD image sensor 11 via the CCU connector 31.

The CCD driver 32 generates a driving pulse such as a horizontal / vertical transfer pulse and a signal charge reset pulse based on the synchronization signal from the DSP 35, and transmits the driving pulse to the CCU connector 31 and the preamplifier / buffer circuit 12. Supplied to the CCD image sensor 11 through the
The CD image sensor 11 is driven.

The camera head 10 is not provided with an optical auto iris mechanism, and its size is reduced. Accordingly, the CCD driver 32 controls the charge accumulation period of the CCD image sensor 11 based on the synchronization signal from the DSP 35, and can adjust the exposure.

The CDS / AGC circuit 33 outputs a SHD pulse (Sample Hold of Data Pulse) and SH from the DSP 35.
A P-pulse (Sample Hold of Pre-charge Pulse) is supplied, the pre-charge level and the data level of the imaging signal supplied via the CCU connector 31 are sampled and held, and the difference is detected. Detects accurate signal level, removes random noise,
Further, the CDS / AGC circuit 3
The gain of 3 itself is automatically controlled, and an image signal having a stable signal level is always output.

The A / D converter 34 is driven based on a sampling pulse from the DSP 35, and supplies the DSP 35 with image data obtained by digitizing an image signal from the CDS / AGC circuit 33.

In the DSP 35, a timing generator 35a inside the DSP 35 generates the synchronizing signal and the sampling pulse, and outputs the SHD pulse and S
Generate an HP pulse. In the DSP 35, digital signal processing such as color matrix adjustment, backlight correction, gamma correction, and negative / positive conversion is performed in synchronization with the sampling pulse. DSP35
For example, it is possible to adjust the hue without changing the reference white color by adjusting the color matrix, or to detect the saturated region and the insufficient light amount region by the backlight correction, and shift the photometry position to an optimum portion. I have.

The electronic zoom circuit 36 enlarges a predetermined area based on the image data from the DSP 35 by 1 to 3 times, and converts the image data obtained by enlarging the predetermined area into a DS again.
Supply to P35.

The video signal output circuit 37 converts the imaging data from the DSP 35 into an NTSC (National Television System).
em Committee) or PAL (Phase Alternation by
The video signal is converted into a video signal of a (Line) system, and the video signal is transmitted to an external device such as a monitor device via the input / output connector 38.

The CCU 30 includes an A / D converter 39, an electronic volume circuit 40 for raising a weak signal to a predetermined level, an external synchronization circuit 41 for performing signal processing by external synchronization, and a flash memory. 42,
For example, an on-screen display (OSD) circuit 43 that outputs color signals such as characters and symbols for menu display, a color bar circuit 44 that generates a color bar,
RS which is an interface with a personal computer
232C drive 45, a write enable (WEN) output circuit 46 for outputting a signal for a long time mode,
A C / DC converter 47 and a microcomputer 48 for controlling the entire apparatus are provided.

The A / D converter 39 converts a voltage value applied to a cable length detecting resistor provided inside the cable 20 into a digital signal, and supplies the digital signal to the microcomputer 48. Microcomputer 48
Recognizes the length of the cable 20 based on the voltage detected by the A / D converter 39, and controls the drive timing of the timing generator 35a and the like according to the cable length.

[0028] Here, the cable 20, as shown in FIG. 3 described above, a resistor R _2. Cable 20 is CCU
When connected to a 30, one end of the resistor R ₂ is connected to the resistor R ₁ in series, the other end thereof is grounded. And the resistance R ₁
When the voltage V _cc is applied to the resistor R ₂ and the A / D converter 39 detects the voltage of the resistor R ₂ , the voltage value V _x
Is digitized and supplied to the microcomputer 48. The resistance value of the resistor R ₂ is determined for each length of the cable 20. For example, when the length of the cable 20 is 2 m, the resistance R ₂ is ₂ kΩ, when it is 3 m, 3 kΩ, and when it is 4 m, it is 4 kΩ.
Ω, 5 m when 5 m.

The microcomputer 48 can detect the length of the cable 20 based on the voltage value V _x. That is,
If V _cc = 5 V and R ₁ = 10 kΩ, then V _x = V _cc · R ₂ / (R ₁ + R ₂ ). For example, if the cable length is 2 m and R ₂ = 2
When kΩ, V _x = 0.83V, cable length 3m
V _x = 1.2 V when R ₂ = 3 kΩ, V _x = 1.4 V when the cable length is 4 m and R ₂ = 4 kΩ, and V _x = 1.4 V when the cable length is 5 m and R ₂ = 5 kΩ V _x = 1.7
V. Therefore, the microcomputer 48 may store this voltage value in advance, by comparing the detected voltage value V _x, can recognize the length of the cable 20.

The electronic volume circuit 40 controls the microcomputer 4 to increase the signal level of, for example, a signal having a small signal level among the synchronization signals separated by the external synchronization circuit 41.
8 to be adjusted.

The external synchronization circuit 41 includes an input / output connector 38
A signal is supplied from, for example, an external personal computer via the CPU, and a synchronization signal, a subcarrier, and the like are separated from the signal, and the phases of the signal and the synchronization signal in the DSP 35 are compared. The external synchronization circuit 41 controls the driving of the timing generator 35a based on the result of the phase comparison so that the synchronization signal and the like in the DSP 35 synchronize with the external synchronization signal and the like.

The flash memory 42 is connected to an external personal computer via an RS232C drive 45 and a microcomputer 48.
The program can be rewritten from the computer. The microcomputer 48 is provided in the flash memory 42.
To the external memory mode for controlling the entire apparatus based on the program of the above, or to the internal memory mode for copying the program of the flash memory 42 to the internal memory and controlling the entire apparatus based on the program of the internal memory. . Therefore, even if the program in the internal memory or the flash memory 42 is destroyed, the microcomputer 48 can control the microcomputer 48 based on the program by writing the program into any one of the above memories using an external personal computer or the like.

The OSD circuit 43 generates red (R), green (G), and blue (B) color signals representing a character for menu display based on the control of the microcomputer 48, and converts these color signals into a color bar. The signal is supplied to a circuit 44.

The color bar circuit 44 generates a color bar signal representing, for example, seven color bars by outputting a predetermined color signal every one vertical scanning period based on the control of the microcomputer 48. OSD circuit 4 for bar signal
3 is supplied to the DSP 35 in a superimposed manner. When the color bar circuit 44 does not output the color bar signal, the color signal supplied from the OSD circuit 43 is supplied to the DSP 35 as it is.

Here, the DSP 35 can selectively output image data subjected to digital signal processing or a color bar signal from the color bar circuit 44. Specifically, the DSP 35 supplies the color bar signal to the video output circuit 37 as it is when the color bar signal is supplied from the color bar circuit 44, and performs digital signal processing when the color bar signal is not supplied. Is supplied.

The RS232C drive 45 is supplied with a control signal from, for example, a personal computer via the input / output connector 38, converts this control signal into a predetermined signal, and supplies it to the microcomputer 48. In other words, the user
Image quality, color tone, and the like can be controlled by a personal computer or the like.

When the charge accumulation period of the CCD image sensor 11 is set to several fields by the microcomputer 48 and the DSP 35 is set to the long-time mode, the WEN output circuit 46 outputs a synchronization signal for the long-time mode. For example, a signal corresponding to the long-time mode is supplied from an external personal computer.

The DC / DC converter 47 includes a DSP 35
In order to supply various kinds of low voltage with little voltage fluctuation to an LSI or an IC such as the electronic zoom circuit 36 or the like, the voltage is converted into a predetermined voltage and supplied.

In the camera device configured as described above, for example, when the cable 20 having a length of 2 m (R ₂ = ₂ kΩ) is attached to the camera head 10 and the CCU connector 31, the resistors R ₁ and R voltage V _cc to a resistor R ₂
= 5V is applied. The microcomputer 48 detects the voltage V _x = 0.83 V of the resistor R ₂ via the A / D converter 39.

The microcomputer 48 based on the detection result of the voltage V _x, the synchronization signal, SHD pulse, so as to correct the timing of generating such SHP pulse, controls the timing generator 35a. Timing generator 35
“a” generates a synchronizing signal and a sampling pulse, and generates an SHP pulse and an SHD pulse corrected by the transmission delay twice as long as the cable 20 (4 m). That is, the timing generator 35a, as shown in FIG.
Generate pulses and SHD pulses.

The CCD driver 32 generates a drive pulse based on the synchronization signal from the timing generator 35a, and supplies the drive pulse to the CCD image sensor 11 via the cable 20. CCD image sensor 1
1 is driven based on a drive pulse and supplies an imaging signal of a subject to the CDS / AGC circuit 33 via the cable 20 or the like.

As shown in FIG. 4, the CDS / AGC circuit 33 is supplied with an image signal delayed by, for example, several ns from the CCD image sensor 11 with respect to the image signal having no transmission delay of the cable 20, and outputs the timing signal. The SHD pulse corrected by the delay and the S
HP pulses are supplied. Therefore, based on the SHD pulse and the SHP pulse, the CDS / AGC circuit 33 can perform the correlated double sampling process by sampling and holding the data level and the precharge level of the imaging signal having the transmission delay, respectively, and perform the reset. It is possible to remove noise and obtain an appropriate imaging signal.

The A / D converter 34 digitizes the image signal supplied from the CDS / AGC circuit 33 based on the sampling pulse from the timing generator 35a and supplies the image data to the DSP 35.

The DSP 35 performs digital signal processing on the image data supplied from the A / D converter 34 in synchronization with the sampling pulse, and transmits the image data to, for example, a monitor device via the video output circuit 37 or the like. I do. The monitor device displays an image of the subject captured by the camera device.

That is, the microcomputer 48 outputs an image pickup signal obtained by driving the CCD image sensor 11 to the CCU 30.
Automatically determines the transmission delay of the cable 20 that occurs before the signal is supplied to the timing generator 35, and controls the timing generator 35a to generate a synchronization signal, a sampling pulse, an SHD pulse, and an SHP pulse according to the transmission delay. it can. Therefore, in the camera device, the cable 2
Since the signal processing of the image pickup signal of the subject is performed without being affected by the signal transmission delay caused by 0, a good image pickup signal can be transmitted to the monitor device or the personal computer.

Next, when the cable 20 having a length of 2 m is replaced and the cable 20 having a length of 5 m (R ₂ = 5 kΩ) is attached to the camera head 10 and the CCU connector 31,
The microcomputer 48 controls the resistance R ₂ via the A / D converter 39.
To detect the voltage V _x = 1.7V.

The microcomputer 48 based on the detection result of the voltage V _x, the synchronization signal, SHD pulse, so as to correct the timing of generating such SHP pulse, controls the timing generator 35a. Timing generator 35
a is a signal that generates a sampling pulse and is corrected by a transmission delay twice as long as the cable 20 (10 m).
Generate HP and SHD pulses. That is, as shown in FIG. 4, the timing generator 35a can generate the SHP pulse and the SHD pulse whose phases are delayed by the transmission delay of the imaging signal.

As described above, in the above camera device, when the cable 20 is connected to the CCU 30, the length of the cable 20 is automatically determined, and the drive timing of the CCD image sensor and the drive of the signal processing system are determined according to the length. By correcting the timing, appropriate signal processing can be performed on the imaging signal obtained by the CCD image sensor. That is, the camera device allows the user to connect the cable 2
Since it is not necessary to perform cable length compensation in the signal processing system every time the length of 0 is changed, the subject can be easily photographed without the trouble of the operation procedure.

The present invention is not limited to the above embodiment unless otherwise specified. For example, if the length of the cable 20 can be specified, the resistance of the resistor R ₂ It goes without saying that the resistance value does not need to be increased according to the length of the cable.

Further, by shifting the phase of either the pulse for driving the CCD driver 32 or the pulse for driving the CDS / AGC circuit 33, the DSP 35, or the like, the signal transmission delay by the cable 20 is corrected. Of course, it may be done.

[0051]

As described in detail above, according to the camera apparatus of the present invention, the timing for driving the image sensor driving means and the signal processing means is controlled based on the detection result of the cable length detecting means. By correcting a phase shift occurring when a signal is supplied via a cable, the image sensor driving unit and the signal processing unit can be appropriately driven. That is, in this camera device, since the signal processing can be performed by correcting the sampling deviation between the image sensor driving unit and the signal processing unit based on the length of the cable, a good imaging signal can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a specific configuration of a camera device according to the present invention.

FIG. 2 is an external view of the camera device.

FIG. 3 is a diagram showing a state in which the length of the cable is determined by a resistance provided on the cable of the camera device.

FIG. 4 is an SHD for performing a correlated double sampling process on an image signal supplied to a CCU of the camera device.
FIG. 4 is a diagram illustrating phases of a pulse and an SHP pulse.

[Explanation of symbols]

32 CCD driver, 33 CDS / AGC circuit, 3
4 A / D converter, 35 DSP, 48 microcomputer

Claims (1)

[Claims] 1. A camera device for supplying an image pickup signal from a camera head to a camera control unit via an exchangeable cable to perform signal processing, wherein the camera head has an image sensor, and the camera control unit is Image sensor driving means for driving the image sensor, cable length detection means for detecting the length of the cable, signal processing means for performing signal processing of the image pickup signal, and a detection result of the cable length detection means. And a control means for controlling timing for driving the image sensor driving means and the signal processing means.