JPH1042305A - Video signal processor which can be connected to electronic endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reproduction of a disturbed video in spite of the connection order of signal lines between the electronic endoscope and a video signal processor by providing an output inhibition means for inhibiting the output of a serial digital video signal while a phase locking detection means detects phase locking. SOLUTION: The phase locking detection circuit 52 is connected to an output control signal processing circuit 54. When the phase clocking detection circuit 52 detects a phase locking state, an output signal level to the output control signal circuit 54 changes from low to high. When a disable/enable signal from the output control signal processing circuit 54 to a parallel/serial converter 26 is the low level, namely, when the phase locking detection circuit 52 does not detected the phase locking state, the parallel/serial converter 26 is in the disable state and the output of the serial digital video signal is stopped. When the signal is in the high level, namely, when the phase locking state is detected, the converter is set to the enable state and the output of the serial digital video signal becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing apparatus connectable to an electronic endoscope, and more particularly to a video signal processing apparatus interposed between an electronic endoscope and peripheral devices such as a TV monitor and an image processing computer. The present invention relates to a video signal processing device.

[0002]

2. Description of the Related Art As is well known, an electronic endoscope includes a scope formed of a flexible conduit, and a distal end of the scope is provided with a solid-state imaging device such as a charge-coupled device (CCD).
e) An image sensor is provided, and this CCD image sensor is combined with an objective lens system. In addition, an illumination light guide made of an optical fiber bundle is inserted into the scope, the end face of the end is located at the tip of the scope of the electronic endoscope, and the other end is connected to a light source. When the scope is inserted into the body cavity of the patient, the front of the objective lens system on the distal end side is illuminated with the light emitted from the end face of the distal end of the light guide, whereby the subject image captured by the objective lens system is solid-state imaging device. Is formed on the light receiving surface. The electronic endoscope further includes a processor that processes a video signal obtained by the solid-state imaging device to generate a video signal, and a video is reproduced on a TV monitor device based on the video signal.

[0003] Usually, an electronic endoscope is configured to reproduce a full-color image in combination with a color monitor device. Since the number of pixels of a solid-state imaging device such as a CCD image sensor used in an electronic endoscope is smaller than the number of pixels of a normal solid-state imaging device, a so-called plane-sequential method is employed. That is, for example, a rotary RGB color filter is interposed between the light source and the illumination light guide, and red light, green light, and blue light are sequentially emitted from the end face of the tip of the light guide, and a subject image is formed. An image is sequentially formed on the light receiving surface of the CCD image sensor with the red light, the green light, and the blue light, and a red image signal, a green image signal, and a blue image signal are read therefrom at predetermined time intervals. Next, the video signal of each color is processed by the above-mentioned processor to be a color video signal, and a full-color video is reproduced on a color monitor device based on the color video signal.

In recent years, video signals obtained by electronic endoscopes are used not only by TV monitors for reproducing images but also by peripheral devices such as video tape recorders, printers, and computers for image processing. It is desired that the processor of the electronic endoscope is configured to output at least two video signals.
In this case, as a TV monitor device, a medical TV monitor device that considers electrical safety measures for a patient is known, but a commercial or consumer TV monitor device is introduced in an actual medical practice. There is also. On the other hand, in the case of peripheral devices such as a video tape recorder, a printer, and a computer for image processing, there is no one developed especially for medical use. Therefore, electrical safety measures for the patient should be provided between the electronic endoscope and its peripheral devices.

On the other hand, for example, when an electronic endoscope is used in an operating room, not only the operating room alone reproduces an image with a TV monitor device, but also the real-time image reproducing in a separate room away from the operating room. Is also desired. The video signal output from the processor of the electronic endoscope is an analog signal, and there is a problem of attenuation of the analog video signal when the video signal is transferred to another room far from the operating room. When a component video signal having the best reproducibility of full-color video is converted to a digital video signal and transferred, the problem of signal attenuation can be solved. A transfer cable including a large number of signal lines corresponding to the number of bits of a signal is required, and it is not practical to convert a component video signal into a digital video signal and transfer it as it is.

Therefore, a video signal processing device has been proposed as an interface processing device interposed between an electronic endoscope and its peripheral devices. The video signal processing device is a video signal output from a processor of the electronic endoscope. Is converted to a peripheral digital device, and a component video signal having the best reproducibility of full-color video is converted to a serial digital video signal and output.

[0007]

In a video signal processing apparatus which converts a component video signal having the best reproducibility of a full-color video into a serial digital video signal and outputs the converted signal, there is no problem of signal attenuation. The serial digital video signal can be transferred to a long distance by a transfer cable including a single signal line. However,
In order to obtain a proper reproduced image by transferring the serial digital video signal, the phase of the output frequency of the serial digital video signal must be matched with the phase of the synchronizing signal of the component video signal. A PLL (phase-locked loop) circuit is required.

As is well known, a PLL circuit controls and locks the phase of an input signal to a predetermined phase. Therefore, the reproduced image obtained by the transfer of the serial digital video signal is disturbed until the synchronization signal is input to the PLL circuit and the phase is matched with the phase of the drive frequency of the parallel / serial converter. Particularly, when connecting the signal line of the component video signal at the last connection between the processor of the electronic endoscope and the video signal processing device, a problem occurs that the disturbance of the reproduced video continues for a long time.

Accordingly, an object of the present invention is to provide a video signal processing apparatus connectable to an electronic endoscope, wherein a component video signal is converted into a serial digital video signal as one of at least two video signals. In a video signal processing device configured so as to be converted into a signal and output and at least two systems of video signals are insulated, a connection of a signal line between the electronic endoscope and the video signal processing device is established. It is an object of the present invention to prevent a disturbed reproduced image from appearing on a TV monitor device in any order.

[0010]

A video signal processing apparatus according to the present invention is connectable to an electronic endoscope, and converts an analog component video signal output from the electronic endoscope into a serial digital video signal. It is configured to output to the outside. According to the present invention, such a video signal processing apparatus locks the phase of the output frequency of the serial digital video signal in accordance with the phase of the synchronization signal of the component video signal, and detects the phase lock of the phase lock means. It is characterized by comprising: a phase lock detecting means for detecting the phase lock; and an output blocking means for blocking the output of the serial digital video signal until the phase lock is detected by the phase lock detecting means.

In the present invention, when the analog component video signal includes a red video signal, a green video signal, and a blue video signal in addition to the synchronizing signal, the video signal processing apparatus according to the present invention preferably further includes the red video signal, ,
Calculating means for generating a luminance signal and two kinds of color difference signals based on the green video signal and the blue video signal; and a digital luminance signal and two kinds of digital color difference signals obtained from the calculating means. Analog / digital conversion means for converting the signals into signals, output control means for outputting a digital luminance signal and two kinds of digital color difference signals obtained from the analog / digital conversion means in a predetermined order, and a predetermined order from the output control means. To output a digital luminance signal and two kinds of digital color difference signals,
Parallel / serial conversion means for generating the serial digital video signal described above, wherein the output blocking means controls the output of the parallel / serial conversion means.

In the present invention, when the analog component video signal includes a red video signal, a green video signal, and a blue video signal as other component signals of the synchronization signal, the video signal processing apparatus according to the present invention preferably further comprises: Analog / digital conversion means for converting each of the component signals into a digital video component signal, digital arithmetic means for creating a digital luminance signal and two kinds of digital color difference signals based on the digital video component signal, and Output control means for outputting the obtained digital luminance signal and two kinds of digital color difference signals in a predetermined order; and outputting the digital luminance signal and two kinds of digital color difference signals in a predetermined order from the output control means. Parallel / parallel to create serial digital video signals
Serial converting means, wherein the output blocking means controls the output of the parallel / serial converting means.

In the present invention, when the analog component video signal includes a luminance signal and two kinds of color difference signals as other component signals of the synchronizing signal, the video signal processing device according to the present invention preferably further comprises the components Analog / digital converting means for converting each of the signals into a digital luminance signal and two kinds of digital color difference signals, and outputting the digital luminance signal and two kinds of digital color difference signals obtained from the analog / digital converting means in a predetermined order. An output control means, and a parallel / serial conversion means for outputting the digital luminance signal and the two kinds of digital color difference signals in a predetermined order from the output control means to create the serial digital video signal. The output blocking means controls the output of the parallel / serial conversion means. It is.

The video signal processing apparatus described above further detects an output system for outputting the analog component video signal itself as it is and an input of a synchronization signal of the analog component video signal, if necessary. A synchronizing signal detecting means for detecting the input of the synchronizing signal by the synchronizing signal detecting means, and an output control means for permitting the output of the analog component video signal. May be output to the outside as an optical serial digital video signal.

When a composite video signal is output as another video signal from the electronic endoscope, the video signal processing apparatus according to the present invention further comprises an output for outputting the composite video signal to the outside. A system may be provided. When an S-video signal including a luminance signal and an AM-modulated chrominance signal is output from the electronic endoscope as other video signals, the video signal processing apparatus according to the present invention further includes the S-video signal. May be provided to the outside. On the other hand, in the video signal processing device according to the present invention, preferably, the input system of the video signal from the electronic endoscope is electrically insulated.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a video signal processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

Referring to FIG. 1, there is schematically illustrated an electronic endoscope to which a video signal processing device according to the present invention is connected.
The electronic endoscope comprises a scope 10 comprising a flexible conduit,
And a processor 12 connected to the scope 10. A CCD image sensor is provided at the tip of the scope 10 as a solid-state imaging device. This CCD image sensor is combined with an objective lens system, and a subject image captured by the objective lens system is formed on a light receiving surface of the CCD image sensor. Let me do.

A light guide composed of a bundle of optical fibers is inserted into the scope 10, and its distal end extends to the distal end surface of the scope 10, and the other end is connected to a light source provided in the processor 12. Connected. The electronic endoscope is configured so as to be able to reproduce a color image in a plane-sequential system. For this reason, for example, a rotary RGB color filter is interposed between the light source and the end face of the light guide, and light from the light source is appropriately applied. The light is condensed on the end face of the light guide by a simple condensing lens system, whereby the subject is sequentially illuminated with red light, green light and blue light. That is, the subject is sequentially illuminated with red light, green light and blue light at predetermined time intervals, and a subject image is formed on the light receiving surface of the CCD image sensor with light of each color.

In the processor 12, video signals of respective colors are sequentially read from the CCD image sensor, and the read signals are output from the processor 12 as video signals after undergoing predetermined image processing such as white balance adjustment processing and gamma correction processing. Is done. The processor 12 of the electronic endoscope includes a composite synchronization signal (SYNC), a red video signal (R), a green video signal (G), and a blue video signal (B) as the first system video signal. Composite video in which a component video signal, an S-video signal composed of a luminance signal and an AM-modulated chrominance signal as a second-system video signal, and a luminance signal and an AM-modulated chrominance signal as a third-system video signal It is configured to output signals respectively.

FIG. 2 is a block diagram showing an embodiment of a video signal processing apparatus according to the present invention. The video signal processing apparatus can be connected to a processor 12 of an electronic endoscope, and the processor 12 has at least A video signal of the first system, that is, a component video signal composed of a composite synchronization signal (SYNC), a red video signal (R), a green video signal (G), and a blue video signal (B) is output. It is assumed that it is configured. As shown, the composite synchronizing signal (SYNC), red video signal (R), green video signal (G), and blue video signal (B) constituting the component video signal are photocouplers 14 ₁ , 14 ₂ , and 14 ₃ , respectively. , 144 ₄ , whereby the composite sync signal (SYNC), the red video signal (R),
The green video signal (G) and the blue video signal (B) are once converted into optical signals and then output again from the respective photocouplers 14 ₁ , 14 ₂ , 14 ₃ and 14 ₄ as analog electric signals. Therefore, each photocoupler 14 ₁ , 1
4 _2, 14 _3, the analog electrical signal output from the 14 ₄ becomes what is insulated from the electronic endoscope. In short, the photocoupler 14 _1, 14 _2, 14 ₃ and 14 ₄ functions as an insulating circuit means.

Analog electric signals output from the photocouplers 14 ₁ , 14 ₂ , 14 ₃ and 14 _4, ie, a composite synchronizing signal (SYNC), a red video signal (R), a green video signal (G), and a blue video signal (B ) Is the amplifier 16 ₁ , 1
Is input to the digital conversion circuit 18 after being amplified by 6 _2, 16 ₃ and 16 _4.

[0022] In detail, the digital conversion circuit 18, a timing generator 20 ₁ is provided, wherein the composite synchronizing signal (SYNC) is input to. The timing generator 20 _1, on the basis of the composite synchronizing signal (SYNC), a horizontal synchronization signal, vertical synchronization signal, clock pulses of different frequencies are generated.

The digital conversion processing circuit 18 is provided with a color conversion matrix circuit 22, into which a red video signal (R), a green video signal (G) and a blue video signal (B) are inputted. In the color conversion matrix circuit 22, based on the red video signal (R), the green video signal (G), and the blue video signal (B), a luminance signal (Y) and two types of color difference signals (Cr = RY; Cb). = BY) is generated. These luminance signal (Y) and color difference signal (Cr; Cb)
Is an analog / digital (A / D) converter 2
0 _2, 20 ₃ and is input to the 20 ₄ are converted into 10-bit digital video signal.

In this embodiment, for example, the A / D converter 2
0 The sampling ₂ digital luminance signal from the (Y), output from the timing generator 20 ₁
It is performed based on a 13.5 MHz clock pulse, while A
/ D converter 20 ₃ and the digital color difference signals from 20 _4; for sampling (Cr Cb), is performed based on a clock pulse of 6.75MHz output from the timing generator 20 _1. That is, the sampling frequency of the digital luminance signal is twice the sampling frequency of the digital color difference signal.

The digital conversion processing circuit 18 is further provided with a multiplexer 24.
It functions as output control means for outputting digital signals output from the / D converters 20 ₂ , 20 ₃ and 20 ₄ in a predetermined order. More specifically, in the present embodiment, the digital luminance signal (Y) and the digital color difference signal (Cr; Cb) are output from the multiplexer 24 to the digital luminance signal (Y), the digital color difference signal (Cr), and the digital luminance signal (Y). And a digital color difference signal (Cb). The output of the digital signal from the multiplexer 24 is driven by the clock pulses output from the timing generator 20 _1, the frequency of the clock pulses at twice the sampling frequency of the digital luminance signal (Y) (13.5MHz) It is 27MHz.

In the present embodiment, for example, in the effective video period of one horizontal scanning line, the sampling number of the digital luminance signal (Y) is 720, and each digital color difference signal (Cr;
The sampling number of Cb) is 360, and the total sampling number is 1,440. Referring to FIG. 3, a digital video signal for one horizontal scanning line obtained in this manner is schematically shown together with an analog video signal from which the digital video signal is based. To transfer such a 10-bit parallel digital video signal from the digital conversion processing circuit 18 to the outside, a clock pulse signal line is required, so a transfer cable including a total of 11 signal lines is required. Becomes However, according to the present invention, the parallel digital video signal obtained from the multiplexer 24 is converted into a serial digital video signal by the parallel / serial converter 26, whereby the serial digital video signal is digitally converted by a coaxial cable composed of a single signal line. The data can be transferred from the conversion processing circuit 18 to the outside. FIG.
As shown in FIG. 7, when the parallel / serial converter 26 converts a parallel digital video signal into a serial digital video signal, the least significant bit (LSB) to the most significant bit (MSB) of the 10-bit parallel video signal
Are output in order toward.

As shown in FIG. 5, an analog conversion processing circuit 30 is provided in a TV monitor device 28 installed at a place far from the place where the electronic endoscope is used, and is output from the digital conversion processing circuit 18. The transferred serial digital video signal is first input to the analog conversion processing circuit 30. The analog conversion processing circuit 30 has the reverse configuration of the digital conversion processing circuit 18 shown in FIG. That is, the analog conversion processing circuit 30 is provided with a serial / parallel converter 32 and a video encoder circuit 34, and the video decoder circuit 34 includes a multiplexer 36 and a timing generator 38 ₁ as shown in FIG.
And digital / analog (D / A) converters 38 ₂ , 38
₃ and 38 _4, and a color conversion matrix circuit 40.

As is apparent from FIG. 5, the serial digital video signal is first converted into a parallel digital video signal by a serial / parallel converter 32, and the parallel digital video signal is input to a multiplexer 36 of a video decoder circuit 34. As is apparent from the above description, the parallel digital video signal includes a digital luminance signal (Y) and a digital color difference signal (Cr; Cb), and these digital signals are generated by the timing generator 38.
Predetermined clock pulses by the D / A converter 38 ₂ output from the _1, is distributed to 38 ₃ and 38 _4. These D
/ A conversion 38 _2, 38 ₃ and 38 analog luminance signal outputted from the ₄ (Y) and the analog color difference signals (Cr; C
b) passes through the color conversion matrix circuit 40 and becomes a red video signal (R), a green video signal (G), and a blue video signal (B) from the analog conversion processing circuit 30 to the TV monitor device 28.
, Where a full-color image is reproduced based on the color video signal.

By the way, in order for the TV monitor device 28 to obtain an appropriate full-color reproduced image, the phase of the composite synchronizing signal and the phase of the output frequency of the serial digital video signal (ie, the phase of the driving frequency of the parallel / serial converter) ) and it is necessary to match and thus the timing generator 20 ₁ phase-locked loop (PL
An L (phase-locked loop) circuit 42 is incorporated.

More specifically, as shown in FIG.
The L circuit 42 includes a synchronization separation circuit 44, a phase comparator 46, a loop filter circuit 47, and a voltage controlled oscillator (VCO) 48.
And a frequency divider 50. The sync separation circuit 44 is amplified by the amplifier 16 ₁ composite synchronizing signal (SYNC) is input, where the horizontal synchronizing signal from the composite synchronizing signal (H-S
YNC) is separated, and this horizontal synchronizing signal is
6 is input. Note that the horizontal synchronization signal (H-SYNC)
Has a predetermined frequency (fh). On the other hand, a clock pulse having an appropriate frequency (fo) is output from the VCO 48,
This clock pulse is input to the phase comparator 46 after being divided by the frequency divider 50 to 1 / n. In the phase comparator 46,
fh and fo / n are compared, and the frequency difference is output from the phase comparator 46 as a voltage signal indicating the phase difference. The voltage signal is input to the loop filter circuit 47, where it is output to the VCO 48 after high frequency noise is removed.
When the voltage signal is input to the VCO 48, the VCO 48 changes the frequency (fo) of the clock pulse in a direction to reduce the frequency difference in the phase comparator 46. In short, VC
O48 operates so that the voltage level of the voltage signal output from the phase comparator 46 becomes zero. Thus, VCO4
8 outputs a horizontal synchronizing signal (H-
SYNC), and its frequency is n times the horizontal synchronization signal (H-SYNC). Note that the electronic endoscope has N
When the TSC method is employed, n is equal to 1,716, and when the PAL method is employed in the electronic endoscope, n is equal to 1,728.

The parallel / serial converter 26 is a VCO 4
The operation is performed based on the clock pulse output from the clock signal 8, that is, the clock pulse that is made to coincide with the phase of the horizontal synchronization signal (H-SYNC). To be more specific, parallel /
In the serial converter 26, since the 10-bit parallel digital video signal is converted into a serial digital video signal, the clock pulse input to the parallel / serial converter 26 is further divided by 1/10, Is 10n times the frequency of the horizontal synchronization signal (H-SYNC),
The conversion from a 10-bit parallel digital video signal to a serial digital video signal is performed based on the tenfold frequency. Thus, it is possible to reproduce an appropriate full-color image on the TV monitor device 28.

As is apparent from FIGS. 2 and 7, the PLL
A phase lock detection circuit 52 is provided in the phase comparator 46 of the circuit 42.
Is connected by the phase lock detection circuit 52 so that the voltage level of the voltage signal from the phase comparator 46 becomes substantially zero, that is, the phase of the clock pulse output from the VCO 48 matches the horizontal synchronization signal. The detected phase lock state is detected. For example, regarding the detection of such a phase lock state, when the voltage level of the voltage signal from the phase comparator 46 becomes substantially zero, the output signal from the phase comparator 46 to the phase lock detection circuit 52 becomes low. This is possible by switching from level to high level.

The phase lock detection circuit 52 is connected to an output control signal processing circuit 54. When the phase lock detection circuit 52 detects a phase locked state, an output signal from the phase lock detection circuit 52 to the output control signal processing circuit 54 is output. Change from low level to high level. The output control signal processing circuit 54 outputs a disable / enable signal to the parallel / serial converter 26. When the output signal from the phase lock detection circuit 52 to the output control signal processing circuit 54 is at a low level, That is, when the phase lock detection circuit 52 does not detect the phase lock state, the disable / enable signal from the output control signal processing circuit 54 to the parallel / serial converter 26 is set to a low level. When the output signal to the output control signal processing circuit 54 is at a high level, that is, when the phase lock detection circuit 52 detects a phase locked state, the output control signal processing circuit 54 disables the parallel / serial converter 26. The / enable signal goes high.

The output control signal processing circuit 54 sends a parallel /
When the disable / enable signal to the serial converter 26 is low, ie, when the phase lock detector circuit 5
2 does not detect the phase locked state,
The serial converter 26 is disabled, and the output of the serial digital video signal therefrom is stopped. On the other hand, when the disable / enable signal from the output control signal processing circuit 54 to the parallel / serial converter 26 is at a high level, that is, the phase lock detector circuit 52
Is detected as a phase lock state, the parallel / serial converter 26 is enabled, and a serial digital video signal can be output therefrom.

In short, until the phase locked state is obtained by the phase comparator 46, the parallel / serial converter 26
Output of the serial digital video signal from the
After the phase locked state is obtained by the phase comparator 46, the output of the serial digital video signal from the parallel / serial converter 26 becomes possible, so that the disturbed video reproduction in the TV monitor device 28 can be prevented. In particular, when connecting the processor of the electronic endoscope to the video signal processing device, the connection of the signal line of the composite synchronizing signal is made by the signal line of the red video signal (R), the green video signal (G) and the blue video signal (B) The situation in which the disturbed image is reproduced on the screen of the TV monitor device 28 for a relatively long time after the connection of the connection is surely avoided.

In the present invention, it is assumed that at least two video signals are output from the video signal processing apparatus, and one of the video signals is a parallel / video signal.
The serial digital video signal output from the serial converter 26 is always used. The video signal of other system, for example, an amplifier 16 _1, 16 _2, 16 ₃ and the composite synchronizing signal from 16 ₄ (SYNC), the red video signal (R), green video signal (G), and blue video signals ( B),
That is, an analog component video signal can be used. That is, as is apparent from FIG.
The composite synchronizing signal (SYNC), red video signal (R), green video signal (G) and blue video signal (B) from 6 ₁ , 16 ₂ , 16 ₃ and 16 ₄ are input to the digital conversion processing circuit 18 on the one hand. However, on the other hand, each is output as it is from the video signal processing device as an analog signal.

More specifically, the composite sync signal (SYNC) from the amplifier 16 ₁ is output directly from the video signal processor, but the red video signal (R) from the amplifiers 16 ₂ , 16 ₃ and 16 ₄ , green The video signal (G) and the blue video signal (B) are output from the video signal processing device via the switch circuit 56. The switch circuit 56 is connected to the output control signal processing circuit 54, its operation is controlled by the synchronization signal detection circuit 58 connected to the output side of the amplifier 16 _1. When the synchronization signal detection circuit 58 detects the output of the composite synchronizing signal from the amplifier 16 _1, and changes the output from the synchronization detection detection circuit 58 to the output control signal processing circuit 54 from the low level to the high level, the output control signal at this time The switching signal from the processing circuit 54 to the switch circuit 56 also changes from a low level to a high level. When the switching signal from the output control signal processing circuit 54 to the switch circuit 56 is at a low level, the switch circuit 5
6 is opened, so that the red video signal (R), the green video signal (G), and the blue video signal (B) are not output from the switch circuit 56, but from the output control signal processing circuit 54 to the switch circuit 56. Is high, the switch circuit 56 is closed, whereby the red video signal (R), the green video signal (G), and the blue video signal (B) are output from the switch circuit 56. become.

Therefore, when connecting the processor of the electronic endoscope to the video signal processing device, the connection of the signal line of the composite synchronizing signal is made by the red video signal (R), the green video signal (G) and the blue video signal (B). Even after the connection of the signal line of the above, until the connection of the signal line of the composite synchronization signal is performed,
Since the output of the red video signal (R), the green video signal (G), and the blue video signal (B) from the switch circuit 56 is blocked, an uncontrollable video signal is output from a peripheral device such as a TV monitor device, a printer or a video recorder. The situation that is sent to the device is prevented.

As is apparent from FIG. 2, in this embodiment, a composite video signal and an S-video signal are also prepared as video signals of other systems than the serial digital video signal. Composite video signal is input to the insulating circuit means or the photocoupler 14 _5, where it is once outputted as again analog electrical signals after being converted into an optical signal. Thus, the analog electrical signal output from the photocoupler 14 ₅ becomes what is insulated from the electronic endoscope. Analog composite video signal outputted from the photocoupler 14 ₅ is output from the video signal processing device after being amplified by the amplifier 16 ₅ to the outside thereof mom. On the other hand, S video signals, i.e. analog luminance signal (Y) and the analog AM modulation chrominance signal (C) are input to the photocoupler 14 ₆ and 14 _7, respectively, where once each again as analog electrical signals after being converted into an optical signal Are output from the photocouplers 14 ₆ and 14 ₇ . Thus, an analog electric signal output from the photo-coupler 14 _6, 14 ₇ becomes those insulated against the electronic endoscope. In its mom from the video signal processing apparatus after an analog electrical signal or an analog luminance signal is output from the photocoupler 14 ₆ and 14 ₇ (Y) and the analog AM modulation chrominance signal (C) is amplified by the amplifier 16 ₆ and 16 ₇ Output to the outside.

The video signal processing apparatus as described above is interposed between the electronic endoscope and peripheral devices such as a TV monitor device, a video tape recorder, a printer, and an image processing computer. Video signals can be sent. Further, in the video signal processing apparatus according to the present invention, when used for the photo-coupler 14 ₁ to 14 _7, no leakage current from such peripheral device reaches the electronic endoscope. Furthermore, in the video signal processing device according to the present invention, the serial digital video signal is transferred to the TV monitor device 28 installed at a place far from the place where the electronic endoscope is used. Not only is the problem of signal attenuation associated with the transfer being eliminated, but also the transfer of the serial digital video signal can be performed with a single coaxial cable.

In the above-described embodiment, the output of the parallel / serial converter 26 (FIG. 2) is connected to the electrical / optical (E /
O) A converter may be connected to convert a serial digital video signal to an optical serial digital video signal and then output the same to the outside. In this case, the optical serial digital video signal is transferred to the outside via an optical fiber cable. In the transmission of an optical serial digital video signal using an optical fiber cable, the transfer loss is smaller than that in the transmission of an electric serial digital video signal using a coaxial cable, so that it is farther from the use site of the electronic endoscope. This is particularly advantageous when transferring a video signal to a different location. For example, in a large hospital having a plurality of buildings, where the use site of the electronic endoscope and the TV monitor room are in different buildings, it is preferable to transfer the serial digital video signal as an optical signal. Further, when a serial digital video signal is transferred as an optical signal, there is a secondary effect that the transfer system can be more strongly electrically insulated from the electronic endoscope. On the other hand, the parallel / serial converter 26 can output two systems of an electric serial digital video signal and an optical serial digital video signal.

When an optical serial digital video signal is transferred, an optical / electric (O / E) converter for converting the optical serial digital video signal into an electric serial digital video signal is provided on the receiving side. is necessary. For example, in the example shown in FIG. 5, the O / E converter is connected to the input side of the serial / parallel converter 32.

In the embodiment shown in FIG. 1, the red video signal (R), the green video signal (G) and the blue video signal (B) inputted to the digital conversion processing circuit 18 are used.
Are first converted into digital video signals by A / D converters 20 ₂ , 20 ₃ and 20 ₄ , and a digital luminance signal (Y) and a digital color difference signal (Cr; Cb) are obtained based on the digital video signals. In this case, a digital color conversion matrix circuit is used in place of the analog color conversion matrix circuit 22.

In the above-described embodiment, the processor 12 of the electronic endoscope outputs a component video signal including a red video signal (R), a green video signal (G), and a blue video signal (B) as component video signals. Although the processor 12 of the electronic endoscope is configured to perform other types of component video signals, for example, an analog luminance signal (Y) and an analog color difference signal (Cr; C).
A component video signal including the signal b) may be output. In this case, the color conversion matrix circuit 22 can be omitted from the digital conversion processing circuit 18.

Further, in the above-described embodiment, one or both of the S-video signal and the composite video signal are subjected to the above-described digital conversion processing to be converted into an electric serial digital video signal and an optical serial digital video signal. It is also possible to output to the outside.

Further, in the above-described embodiment, the photocoupler is used as the insulation circuit means, but an insulation transformer can be used as another insulation circuit means. In this case, an electric signal from the processor 12 of the electronic endoscope is input to the primary side of the isolation transformer, and the secondary side of the isolation transformer is connected to an amplifier (16 ₁ , 16 ₂ , 16 ₃ , 1).
6 ₄ , 16 ₅ , 16 ₆ , 16 ₇ ).

[0047]

As is apparent from the above description, according to the present invention, various video signals obtained from an electronic endoscope can be safely used in various peripheral devices, and clear images can be obtained. Can be sent far away from the point of use of the electronic endoscope and the reproduction of unpleasant disturbed images can be avoided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an electronic endoscope to which a video signal processing device according to the present invention is connected.

FIG. 2 is a block diagram showing a first embodiment of a video signal processing device according to the present invention.

FIG. 3 is a schematic diagram showing a digital video signal processed by a video signal processing device according to the present invention and its original analog video signal in comparison.

FIG. 4 is a detailed view of the parallel / serial converter shown in FIG. 2;

5 is a block diagram of an analog conversion processing circuit for performing analog processing on an electric serial digital video signal transferred from the digital conversion processing circuit of FIG. 2;

FIG. 6 is a detailed block diagram of the video decoder circuit shown in FIG.

FIG. 7 is a phase-locked loop (PLL) shown in FIG. 2;
It is a detailed diagram of a circuit.

[Explanation of symbols]

10 Scope 12 processor 14 _{1-14 7} photocoupler _{161-164 7} amplifier 18 the digital conversion circuit 20 _first timing generator 20 ₂ 20 ₄ analog / digital (A / D) converter 22 color conversion matrix circuit 24 multiplexer 26 parallel / Serial converter 28 TV monitor device 30 analog conversion processing circuit 32 serial / parallel converter 34 video decoder 36 multiplexer 38 ₁ timing generator 38 _{2 to} 38 ₄ digital / analog (D / A) converter 40 color conversion matrix circuit 42 phase Lock loop (PLL) circuit 44 Synchronization separation circuit 46 Phase comparator 47 Loop filter 48 Voltage controlled oscillator (VCO) 50 Divider 52 Phase lock detection circuit 54 Output control signal processing circuit 56 Switch circuit 8 synchronization signal detection circuit

Claims (9)

[Claims] 1. A video signal processing device connectable to an electronic endoscope, wherein the video signal processing device is configured to convert an analog component video signal output from the electronic endoscope into a serial digital video signal and output it to the outside. In the video signal processing apparatus, a phase lock unit that locks the phase of the output frequency of the serial digital video signal in accordance with the phase of the synchronization signal of the component video signal, and a phase that detects the phase lock of the phase lock unit A video signal processing apparatus comprising: a lock detection unit; and an output blocking unit that blocks output of the serial digital video signal until the phase lock is detected by the phase lock detection unit. . 2. The video signal processing device according to claim 1, wherein the analog component video signal includes a red video signal, a green video signal, and a blue video signal in addition to a synchronization signal. Calculating means for generating a luminance signal and two kinds of color difference signals based on the video signal and the blue video signal; and a digital luminance signal and two kinds of digital color difference signals respectively obtained from the calculating means. Analog / digital conversion means for converting the digital luminance signal and two types of digital color difference signals obtained from the analog / digital conversion means into a predetermined order; and a predetermined order from the output control means. A digital luminance signal and two types of digital color difference signals are output, and the serial digital video signal is output. ; And a parallel / serial conversion means for forming said output inhibiting means is the parallel /
A video signal processing device for controlling an output of a serial conversion means. 3. The video signal processing apparatus according to claim 1, wherein the analog component video signal includes a red video signal, a green video signal, and a blue video signal as other component signals of a synchronization signal, and further includes the component signal. Analog-to-digital conversion means for converting each of them into a digital video component signal; digital arithmetic means for creating a digital luminance signal and two types of digital color difference signals based on the digital video component signal; An output control means for outputting a digital luminance signal and two kinds of digital color difference signals in a predetermined order; and a digital luminance signal and two kinds of digital color difference signals in a predetermined order from the output control means, and Parallel / serial conversion means for generating a signal. Blocking means is the parallel /
A video signal processing device for controlling an output of a serial conversion means. 4. The video signal processing device according to claim 1, wherein the analog component video signal includes a luminance signal and two types of color difference signals as other component signals of a synchronization signal. Analog / digital conversion means for converting into a digital luminance signal and two kinds of digital color difference signals; output control means for outputting a digital luminance signal and two kinds of digital color difference signals obtained from the analog / digital conversion means in a predetermined order; A parallel / serial converter for generating the serial digital video signal by outputting a digital luminance signal and two kinds of digital color difference signals in a predetermined order from the output control means; /
A video signal processing device for controlling an output of a serial conversion means. 5. The video signal processing device according to claim 1, further comprising: an output system for outputting the analog component video signal itself to the outside as it is; Synchronous signal detecting means for detecting an input of a synchronous signal of a video signal, and output control means for permitting output of the analog component video signal when an input of a synchronous signal is detected by the synchronous signal detecting means. A video signal processing device comprising: 6. The video signal processing device according to claim 1, wherein said serial digital video signal is output to the outside as an optical serial digital video signal. apparatus. 7. The video signal processing device according to claim 1, wherein a composite video signal is output from the electronic endoscope as another video signal, The video signal processing apparatus further comprises an output system for outputting the composite video signal to the outside. 8. The video signal processing device according to claim 1, wherein an S-video signal including a luminance signal and an AM-modulated color difference signal is output from the electronic endoscope as another video signal. A video signal processing device, wherein the video signal processing device further comprises an output system for outputting the S-video signal to the outside. 9. The video signal processing apparatus according to claim 1, wherein an input system of a video signal from the electronic endoscope is electrically insulated. Signal processing device.