METHOD FOR DETERMINING THE DISTANCE OF AN OBJECT FROM AN EDOSCOPE

• US 3,608,547 A
• Filed: 07/24/1968
• Issued: 09/28/1971
• Est. Priority Date: 07/29/1967
• Status: Expired due to Term

• Current Assignee: Masaaki Sato, Shinya Kosaka, Shoichi Saito
• Original Assignee: Masaaki Sato, Shinya Kosaka, Shoichi Saito
• Inventors: Sato, Masaaki, Saito, Shoichi, Kosaka, Shinya
• Primary Examiner(s): Gaudet, Richard A.
• Assistant Examiner(s): Dunne, G. F.
• Application Number:
  US04/747,224
• Time in Patent Office: 1,161 Days
• Field of Search: 128/4,6,397,398,2 356/4,5 250/205 95/11
• US Class Current: 600/109
• CPC Class Codes: A61B 1/00165 with light-conductive means, e.g. fibre optics A61B1/07 takes precedence
• CPC Class Codes: A61B 1/00177 for 90 degrees side-viewing
• CPC Class Codes: A61B 1/04 combined with photographic or television appliances
• CPC Class Codes: G01C 3/00 Measuring distances in line of sight; Optical rangefinders tapes, chains or wheels for measuring length G01B3/00; active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves, G01S17/48
• CPC Class Codes: G03B 37/005 Photographing internal surfaces, e.g. of pipe, G03B37/02 - G03B37/06 take precedence; instruments for performing medical examinations of cavities or tubes of the body by photographic inspection A61B1/00

Abstract

Method for determining the distance of an object from an endoscope which comprises the steps of emitting a light of predetermined intensity and receiving the light reflected from the object having substantially the same reflecting power over the entire area thereof by a photoelectric element, the intensity of the reflected light being the function of the distance from the object, the photoelectric element produces an electrical signal corresponding to the distance. The signal thus produced is recorded and compared with a previously prepared chart indicating the relation between the signal and the distance so that the distance is determined after the operation of the endoscope is completed. The spectroscopic characteristics of the light used for determining the distance is so selected that the film contained in the endoscope for photographing the object is not affected by the light used for determining the distance so that the determination of the distance can be made during the operation of the endoscope. The intensity of the light used for determining the distance is made variable for the better observation of the object while the output of the photoelectric element is varied in inverse proportion to the variation in the intensity of the light so that the correct determination of the distance can be made even though the intensity of the light source is varied.

Claims

1. Method for determining the distance between an object having substantially the same reflecting power over the entire area thereof and the forward end portion of an endoscope adapted to be inserted into a hollow portion of a living body or the like and through which the object is photographed, said endoscope comprising a control housing connected to said forward end portion through an elongated flexible tube, wherein the improvement comprises the steps of emitting a light of a predetermined constant intensity from said forward end portion so as to illuminate the object for photographing same, receiving the light reflected from the object by a light-receiving photoelectric element provided in said forward end portion to thereby generate an electrical signal corresponding to the variation in the intensity of the light received by said photoelectric element, determining the exposure time in response to said electrical signal for the proper exposure of the object, and detecting said determined exposure time so as to record same, thereby permitting the distance between the object and the forward end portion of the endoscope to be determined on the basis of the thus-recorded exposure time which is the function of the intensity of the light reflected from the object and received by said photoelectric element which is in turn the function of the distance between the object and the forward end portion of the endoscope.

2. Method according to claim 1, further comprising the step of amplifying said electrical signal by a DC amplifier connected between said photoelectric element and a timing circuit for determining the exposure time which is in turn connected to a switching circuit, said switching circuit being actuated by said timing circuit so as to terminate the illumination of the object after the proper exposure time as set by said timing circuit has elapsed.

3. Method for determining the distance between an object having substantially the same reflecting power over the entire area thereof and the forward end portion of an endoscope adapted to be inserted into a hollow portion of a living body or the like and through which the object is photographed, said endoscope comprising a control housing connected to said forward end portion through an elongated flexible tube, the illumination of the object for the photographing thereof being effected by an illuminating means suitable for the exposure of the film contained in the forward end portion of the endoscope and having such photosensitive characteristics that the film is not sensitive over a certain range of the wavelengths of the light, wherein the improvement comprises the steps of emitting from another illuminating means provided in said forward end portion a light of a predetermined constant intensity and having a range of the wavelengths to which said film is not sensitive so as to illuminate the object, receiving the ligHt emitted from said another illuminating means and reflected from the object by a light-receiving photoelectric element provided adjacent to said another illuminating means and adapted to be energized thereby so as to generate an electrical signal corresponding to the variation in the intensity of said light received by said photoelectric element, and indicating and/or recording said electrical signal of said photoelectric element to thereby permit the distance between the object and the forward end portion of the endoscope to be determined on the basis of the indication and/or the record of said electrical signal which is the function of the intensity of the light emitted from said another illuminating means and received by said photoelectric element after it is reflected from the object which is in turn the function of the distance between the object and the forward end portion of the endoscope, while the film is not affected by the light emitted from said another illuminating means and reflected from the object.

4. Method according to claim 3, wherein the film is of the tungsten type and said another illuminating means is comprised of a luminous diode made of an arsenic-gallium compound.

5. Method for determining the distance between an object having substantially the same reflecting power over the entire area thereof and the forward end portion of an endoscope adapted to be inserted into a hollow portion of a living body or the like and from which an image of the object formed therein by means of an objective lens system is transmitted through an image-transmitting optical system such as a fiber optical system extending from said forward end portion through an elongated flexible tube to a control housing connected to said forward end portion through said elongated flexible tube so as to be viewed through an ocular means provided in said housing, wherein the improvement comprises the steps of emitting a light of a predetermined intensity so as to illuminate the object, receiving the light reflected from the object by a photoelectric element provided in the endoscope to thereby generate an electrical signal corresponding to the variation in the intensity of the light received by said photoelectric element, and indicating and/or recording said electrical signal to thereby permit the distance between the object and the forward end portion of the endoscope to be determined on the basis of the indication and/or the record of said electrical signal which is the function of the intensity of the light received by said photoelectric element which is in turn the function of the distance between the object and the forward end portion of the endoscope.

6. Method according to claim 5, further comprising the steps of adjusting the intensity of the light for illuminating the object by means of an adjusting means so as to make the intensity of the light suitable for viewing the object illuminated thereby, varying said electrical signal generated by said photoelectrical element in inverse proportion to the variation in the intensity of the light by means of a compensating means operatively connected to said adjusting means so as to compensate therefor so that the distance between the object and the forward end portion of the endoscope is correctly determined despite the intensity of the light received by the photoelectric element is varied by the adjustment of the intensity of the light illuminating the object.