Signal processing circuit adaptable to electronic endoscopes having different lengths

• US 5,434,615 A
• Filed: 09/13/1993
• Issued: 07/18/1995
• Est. Priority Date: 09/25/1992
• Status: Expired due to Term

• Current Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Inventors: Matumoto, Seizi
• Primary Examiner(s): Britton, Howard W.
• Application Number:
  US08/119,592
• Time in Patent Office: 673 Days
• Field of Search: 348/72, 348/518
• US Class Current: 348/72
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 25/00 Circuitry of solid-state image sensors [SSIS]; Control thereof

Abstract

A signal processor apparatus is adaptable to electronic endoscopes having different lengths without the need for changing the operation timing when sampling a video signal. A sampling pulse generator incorporating a phase varying means is disposed in the operating portion or the connecting portion (setup board) of an electronic endoscope. A sampling pulse having the timing corresponding to the length of the electronic endoscope is formed by varying the phase of the sampling pulse by the phase varying means. The sampling pulse generator may be disposed together with a sample-and-hold circuit, a driving circuit of a CCD and the like. Since it is possible to sample and hold the video signal by using the sampling pulse which is correspondent with the length of the electronic endoscope, effective picture signal processing by the processor apparatus is enabled.

Claims

1. A signal processing circuit for an electronic endoscope, the electronic endoscope having an operating portion, a connecting portion and a solid-state image sensor, said signal processing circuit comprising:

a sampling pulse generator for generating a sampling pulse of a video signal, the sampling pulse generator being disposed within the electronic endoscope except at an end portion of the electronic endoscope which has the solid-state image sensor;

a phase varying means which is incorporated into said sampling pulse generator for varying the phase of said sampling pulse so that said sampling pulse has a timing corresponding to a length of said electronic endoscope; and

a sample-and-hold circuit for sampling and holding said video signal output from said solid-state image sensor by using said sampling pulse whose phase is adjusted by said phase varying means, wherein said sampling pulse generator incorporating said phase varying means is disposed in either of the operating portion and the connecting portion of said electronic endoscope.

2. A signal processing circuit for an electronic endoscope according to claim 1, wherein said sample-and-hold circuit having said phase varying means and said sampling pulse generator are disposed in either of the operating portion and the connecting portion of said electronic endoscope.

3. A signal processing circuit for an electronic endoscope according to claim 1, wherein a differential delay noise eliminating circuit is provided as said sample-and-hold circuit.

4. A signal processing circuit for an electronic endoscope according to claim 1, further comprising:

a housing portion having a removable cap which is disposed at an end portion of said operating portion of said electronic endoscope, and which accommodates a circuit board provided with at least said sampling pulse generator having said phase varying means.

5. A signal processing circuit for an electronic endoscope according to claim 1, wherein a correlated double sampling circuit utilizing a clamping pulse and a sampling pulse which are correlated with each other is provided as said sample-and-hold circuit, and said sampling pulse generator adjusts the phases of said clamping pulse and said sampling pulse by said phase varying means.

6. A signal processing circuit for an electronic endoscope according to claim 4, wherein either of said correlated double sampling circuit and said differential delay noise eliminating circuit is disposed in a processor apparatus.

7. A signal processing circuit for an electronic endoscope, the electronic endoscope having an operating portion, a connecting portion and a solid state image sensor, the signal processing circuit comprising:

a phase varying circuit including a variable resistor and a capacitor for forming a pulse having timing corresponding to a length of the electronic endoscope;

a sampling pulse generator, which incorporates said phase varying circuit, which is disposed in either of the operating portion and the connecting portion of said electronic endoscope, and which forms a clamping pulse on the basis of the output of said phase varying circuit and forms a sampling pulse whose phase is shifted from said clamping pulse by a predetermined amount by a resistor and a capacitor provided at a next stage to said phase varying circuit; and

a correlated double sampling circuit for sampling a video signal output from the solid-state image sensor of said electronic endoscope by using said clamping pulse and said sampling pulse which are correlated with each other and which are produced by said sampling pulse generator.

8. A signal processing circuit for an electronic endoscope, wherein a driving circuit for driving said solid-state image sensor is disposed in either of an operating portion and a connecting portion of said electronic endoscope together with said sampling pulse generator incorporating said phase varying means.