JPH07241271A - Circuit of electronic endoscope device - Google Patents

Abstract

PURPOSE:To accelerate the making of an image processing circuit into one chip and to maintain the isolation of a circuit satisfactorily. CONSTITUTION:One digital signal processor(DSP) 12 provided at the post-stage of a CCD 10, and a sample-and-hold (CDS, etc,) circuit 13, an automatic gain control(AGC) circuit 14, a gamma correction circuit 15, a detail circuit 16, an A/D converter 17, image memory 18 (that can be out-fitted to the DSP 12)in which a video signal is stored once, a D/A converter 19 and an encoder 20 (or RGB matrix circuit) are formed in the DSP 12. A photocoupler or an isolation device 22 such as a pulse transformer, etc., is arranged at the post-stage of the DSP 12, and thereby a prescribed dielectric breakdown strength can be maintained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic endoscopic apparatus, and more particularly to a structure of a signal processing circuit in which an isolation device is arranged in consideration of patient safety.

[0002]

2. Description of the Related Art An electronic endoscope apparatus has a CCD (Charge Coupled Device), which is a solid-state image pickup device, disposed at the tip of an electronic scope to observe the inside of a body cavity such as the digestive tract. FIG. 2 shows a circuit configuration of a conventional electronic endoscope apparatus. As shown in FIG.
A signal processing circuit 2 for performing image processing such as white balance is connected, and the signal processing circuit 2 is connected to an A / D converter 4, an image memory 5, a D / A via an isolation device 3.
It is connected to the converter 6. As the isolation device 3, a photo coupler, a pulse transformer, or the like is used. The video signal output from the D / A converter 6 is sent to a monitor 8 via an output circuit 7 such as an encoder.
Is supplied to.

According to the above configuration, the circuit on the front side from the isolation device 3 is the circuit on the patient side, and the circuit on the rear side is the output side (secondary side) circuit. 3 to the next side circuit
The withstand voltage of 4 kV / min or higher is maintained, which ensures safety for patients.

[0004]

By the way, in the above-mentioned electronic endoscope apparatus, there is a demand for downsizing, weight reduction, and cost reduction. For this purpose, the circuit is reduced in size and weight by one chip or the like. Is needed. Therefore, conventionally, the portion of the signal processing circuit 2 described above is formed as a one-chip digital signal processor.

However, the isolation device 3 described above cannot be included in the digital signal processor, and due to the existence of the isolation device 3, the circuits other than the signal processing circuit 2 are integrated into one chip. There is no situation. In recent years, most of the image processing circuits have been housed in electronic scopes to simplify the system.
Acceleration of chips is desired.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic endoscope apparatus which can promote the integration of a circuit into one chip and can maintain good circuit isolation. To provide a circuit.

[0007]

In order to achieve the above object, the present invention provides a signal processing circuit for subjecting a video signal input from a solid-state image pickup device to predetermined signal processing, and an output from this signal processing circuit. An isolation device, which includes at least an output circuit for outputting a video signal to a monitor, forms one digital signal processor and maintains a predetermined withstand voltage in a subsequent stage or a preceding stage of the digital signal processor. It is characterized by being arranged.

[0008]

According to the above construction, a circuit (a memory may be excluded) from a signal processing circuit provided in a subsequent stage of the solid-state image pickup device to a monitor for outputting to a monitor is a single chip. Is a digital signal processor,
An isolation device is attached to, for example, the subsequent stage of the digital signal processor. Therefore, in this case, the circuit up to the digital signal processor is the patient side circuit, and the rear stage side of this processor is the secondary side circuit, and a predetermined dielectric strength voltage is maintained between the patient side circuit and the secondary side circuit.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit configuration of an electronic endoscope apparatus according to an embodiment. As shown in FIG.
1 in 0 digital signal processor (DSP-Digi
tal Signal Processor) 12 is connected. This DSP
In 12, a sample hold (CDS etc.) circuit 13,
Automatic gain control (AGC-Automatic Gain Control) circuit 14, gamma correction circuit 15, detail circuit 16 for processing such as edge enhancement, A / D converter 17, image memory 18 for temporarily storing video signal, D / A A converter 19 and an encoder 20 are formed. The image memory 18
May be externally connected to the DSP 12. Then, an isolation device 22 such as a photocoupler or a pulse transformer is attached to the subsequent stage of the DSP 12, and a monitor 24 is connected to the isolation device 22 via a buffer amplifier 23.

According to the above circuit, the video signal output from the CCD 10 is sampled and held by the sample and hold circuit 13 for each predetermined signal, and the output signal of the sample and hold circuit 13 is clamped by the automatic gain control circuit 14. Simultaneously with the processing, it is amplified with a predetermined amplification factor. Next, the video signal is subjected to gamma correction (correction of the characteristics of the output signal with respect to the input signal) in the gamma correction circuit 15, and contour enhancement processing is performed in the detail circuit 16 to, for example, R (red), G ( Green), B (blue) signals, Y (luminance), C
(Color) signal. Each video signal is temporarily stored in the image memory 18 via the A / D converter 17, read out at a predetermined read speed, and output to the encoder 20 via the D / A converter 19. In the encoder 20, for example, the RGB signal or the YC signal is converted into a predetermined signal which is displayed on the monitor 24.

The video signal output from the encoder 20 passes through the isolation device 22, and when the isolation device 22 is a photocoupler, the video signal is optically converted and then electrically converted again. Therefore, the isolation device 22 electrically separates the signal lines, and a withstand voltage of 3 to 4 kV / min or more is secured here. Then, the output of the isolation device 22 is supplied to the monitor 24 via the buffer amplifier 23, whereby the image captured by the CCD 10 is displayed on the monitor 24.

In the above-described embodiment, the isolation device 22 can be arranged after the buffer amplifier 23. In this case, it is preferable to use a video transformer as the isolation device 22. Further, although the encoder 20 is used as the output circuit in the above, another circuit such as an RGB matrix circuit that executes an output process to the monitor 24 can be used instead of the encoder 20.

According to the configuration of the above embodiment, the CCD 10
From the sample hold circuit 13 in the subsequent stage to the encoder 20
The circuits up to (the image memory 18 may be externally attached) are formed in one chip as the DSP 12, and the DSP 1
It is possible to separate the two up to 2 by the patient side circuit and the circuit after the buffer amplifier 23 as the secondary side circuit by the isolation device 22. Therefore, there is an advantage that the circuit for image processing can be formed into almost one chip, and at the same time, the safety for the patient can be maintained.

The isolation device 22 described above is used.
Can be arranged between the CCD 10 and the DSP 12, and as the isolation device 22, a photo coupler or a pulse transformer can be used.

[0015]

As described above, at least the signal processing circuit for performing the predetermined signal processing on the video signal and the output circuit for performing the output processing on the video signal to the monitor are included in one digital unit. Since the signal processor is formed and the isolation device for maintaining a predetermined withstand voltage is arranged at the rear stage or the front stage of the digital signal processor, it is possible to promote the integration of the circuit into a single chip in the circuit of the electronic endoscope apparatus, and at the same time, the circuit. Has the advantage of maintaining good isolation.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of an electronic endoscope apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a conventional electronic endoscope apparatus.

[Explanation of symbols]

 1, 10 ... CCD, 3, 22 ... Isolation device, 8, 24 ... Monitor, 12 ... Digital signal processor (DSP), 13 ... Sample and hold circuit, 20 ... Encoder, 23 ... Buffer amplifier.

Claims (1)

[Claims] 1. A signal processing circuit for performing predetermined signal processing on a video signal input from a solid-state image sensor, and an output circuit for performing output processing on a monitor of a video signal output from the signal processing circuit. A circuit of an electronic endoscope apparatus in which at least one digital signal processor is formed, and an isolation device for maintaining a predetermined withstand voltage is arranged in a subsequent stage or a preceding stage of the digital signal processor.