JPS63209375A - Video processor for electronic endoscope - Google Patents

Abstract

PURPOSE:To facilitate the adjustment of timing by varying phase difference between a video signal and a timing signal which samples or clamps the video signal. CONSTITUTION:An one-shot multivibrator 11 generates a pulse 4B replying to the rise of a CCD drive pulse 4A. A delay line 12 delays the one-shot pulse 4B and a NOT 13 inverts the pulse 4B. An S/H pulse 4E is obtained by outputting the AND of delay output 40 and inversional pulse 4D with the aid of an AND circuit. The width of the S/H pulse 4E is fixed by the delay quantity but as the width of the one-shot pulse 4B can be set at the optional level by an adjustment volume 10, the time difference between the rise of the drive pulse 4A and the S/H pulse 4E can be set at the optional level.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video processor for an electronic endoscope.
In particular, the present invention relates to a circuit for setting the timing of sample-holding and clan fA7D conversion of a video signal from a solid-state image sensor.

[Conventional technology]

In conventional endoscope devices using solid-state imaging devices, when the length of the scope changes, the adjustment of the driving signal of the imaging device and the fine adjustment of the timing of video signal processing are automatically performed. In addition, a resistor for model discrimination is provided inside the scope, and a circuit that detects the resistance in the video processor section and identifies the scope model, and a matching element switching circuit that switches the adjustment based on the identification signal.A timing switch. It is equipped with a circuit.

Such conventional endoscope devices are disclosed in, for example, Japanese Patent Application No. 60-225368 and Japanese Patent Application No. 60-23308 filed by the applicant.
It is disclosed in No. 8.

[Problem that the invention seeks to solve]

In such conventional technology, a model discrimination resistor is provided inside the endoscope, and the video processor detects the resistance to identify the scope model.Based on this, the timing of sample hold, clamp, and N-conversion is determined. However, because the entire circuit is complicated, it is expensive9 and adjustment is difficult.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a video processor circuit that can easily adjust the timing of sample hold, clamp, and Φ conversion with a simple circuit configuration at low cost and with high accuracy.

[Means and operations for solving the problems] In order to solve the above-mentioned conventional problems, the video processor of the present invention includes a video signal from a solid-state image sensor and a timing signal for sampling or clamping this video signal. It is characterized by being able to vary the phase difference between the two.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to the drawings.

Basic Concept First, the basic concept of the present invention will be explained with reference to FIG.

An example using a CCD as a solid-state image sensor will be described.

The waveform shown in FIG. 1A is a drive pulse for outputting a video signal pixel by pixel from the COD.

The waveform in FIG. 1B is the video signal read out by the drive pulse IA. The waveform shown in FIG. 1C is a pulse for sample-holding (sA) the video signal IB, and it is necessary that the timing matches near the center of the video signal. However, in reality, the COD is located at the tip of the scope, and the Pidio processor is placed 2 to 4 physical distances from there. Because of this distance of 2 to 4 meters, there is a time difference between the CCD drive pulse in the video processor and the video signal output from the COD and input to the preamplifier (Figure 1D: preamplifier input waveform). For this reason, Innoculus generates a waveform delayed by this time difference (
(see Figure 1E). The time difference required here differs depending on the length of the scope, but the present invention allows the knee to adjust this time difference by himself.
The optimum delay itTn is obtained. Such adjustment of the delay amount can be performed using a one-piece multivibrator with a variable pulse width of 1', as shown in the following embodiments.

Electronic Endoscope Apparatus Next, an electronic endoscope apparatus, which is an embodiment incorporating the above-mentioned basic concept of the present invention, will be described with reference to FIGS. 2 to 4.

First, in FIG. 2, a video signal captured by a CCD 1 is amplified to a predetermined level by a preamplifier 2, sampled and held by an S/H 3, and unnecessary carrier components in the video signal are removed. After this, gamma correction 4 is used to correct gamma according to the characteristics of the monitor, and A/D converter 5 is used to convert the A/D
It is converted into a digital signal. In this example, R, G,
Since the B-side sequential method is adopted, the signals up to this point are R, G, and B input in chronological order. This digital signal is stored in a digital memory 6 and subjected to D/A conversion using a D/A converter 7, and R, G, and B are output simultaneously, resulting in a video signal that can be observed on a monitor. simultaneous processing). The pulse generator 8 generates a CCD drive pulse pulse, a memory address, and a D/A clock as shown in FIG. 4, and supplies them to each block. The variable delay output 9 outputs S/l/4 pulses from the CCD drive pulse, and the amount of delay TD can be varied using the adjustment volume 10.

Next, adjust the variable delay one-point 9 and the adjustment point 1.
A concrete example of 0 is shown in FIG. Also, Figure 4 shows
3 represents signal waveforms at various parts of the circuit of FIG. 3.

In FIG. 3, a one-shot multivibrator 1 is provided which receives a CCD drive pulse, and its output is supplied to a NOT gate 13 and a delay line 12. These outputs are supplied to AND dart 14. This A
The output of the ND gate 14 is sampled and held by the circuit S/) (
Supply to 3. As is clear from Figure 3, this one-shot multivibrator 1) has an adjustment of 10 degrees.
is provided, whereby the operation timing of the one-shot multivibrator 11 can be adjusted.

Next, the operation shown in FIG. 3 will be explained with reference to FIG. 4.

In response to the rising edge of the COD drive pulse shown in FIG. 4A, the one-shot multivibrator 11 operates with a pulse width T
Generates D's lumbar rus (Figure 4B).

On the other hand, the y erase line 12 delays the one-shot signal 9 pulse 4B by the delay amount TP (FIG. 4C).

NOT J J has the function of inverting the one-shot pulse 4B (Figure 4D). AND 14 outputs the AND (logical product) of delay output 4C and inverted pulse 4D, and 87H/# pulse (FIG. 4E) is obtained.

The pulse width TP of this S/H pulse 4E is fixed at the delay amount determined by the characteristics of the delay line 12, but the width TD of the one-shot pulse can be adjusted by the ream 10.
Since it can be set to any value by C0D)', the time difference (
The delay jtTo) can also be set to any value. In reality, this time difference is determined by the length of the scope, but in this example, it is possible to adjust the IJ Neem 10 according to the scope used by the user (doctor). Optimal S/)l timing can be obtained.

In the above-mentioned embodiment, the S/H timing was described, but it is also possible to set the S/H timing to the optimum position using the same method. Furthermore, the present invention is not only compatible with correlated double sampling, but also can be easily applied to the flange method disclosed in Japanese Patent Application No. 225368/1988 filed by the present applicant.

〔Effect of the invention〕

According to the present invention, there are various effects as described below.

1) Adjustment with one shot, delay line, NOT dart, AND dart? It is inexpensive because it can be constructed with only a pump, has a small number of parts, and does not require adjustment at the factory.

2) It has a small number of parts, can be easily integrated into an IC, and is highly reliable.

3) For any length scope, the user can
One adjustment? It has the effect of easily obtaining high-quality endoscopic images simply by using Reime v4.

[Brief Description of the Drawings] Fig. 1 is a diagram for explaining the basic concept of the video processor of the present invention, and Fig. 2 is a block diagram of a circuit of an electronic endoscope device using the video processor of the present invention. 3 is a specific circuit diagram of the variable delay one-shot shown in FIG. 2, and FIG. 4 is a waveform diagram of each part of the circuit shown in FIG. 3. 1...CCD, 9...Sample hold circuit, 4
...γ correction circuit, 5...ψ converter, 6...; frame memory, 7... D/A converter, 8... pulse generator, 9... variable delay one shot, 10...
...Adjustment Goliame, 11...One-shot multivibrator, 12...Delay line. Applicant's agent Patent attorney Atsushi Tsuboi 4D 4
Inverted pulse of B pulse 4E S/H pulse 4E=40 AND 4D -To An-

Claims (1)

[Scope of Claims] 1) An endoscope that uses a solid-state image sensor or an adapter that uses a solid-state image sensor is connected, and a video signal for an electronic endoscope that converts a video signal from the image sensor into a television signal. A video processor for an electronic endoscope, characterized in that the processor comprises variable delay means that can vary the phase difference between the video signal and a timing signal for sampling or clamping the video signal. 2) The video processor according to claim 1, wherein the variable delay means includes at least a one-shot multivibrator with a phase difference adjustment member and a delay line. 3) The video processor according to claim 2, wherein the phase difference adjustment member is installed at a position of the electronic endoscope where the phase difference adjustment member can be directly adjusted by a user.