Automatic envelope measuring system

A system for determining the clearance envelope associated with a path of travel and objects disposed along the length of and spaced from said path of travel comprising

• means for directing a beam of coherent light for rotation about an axis of rotation parallel to the direction of and radially about said path of travel,
• a television camera directed in a direction parallel to said axis of rotation, said television camera being responsive to light reflected by objects disposed along said path of travel for providing an analog video signal indicative of the distance between the camera and said objects,
• means for scanning the field of said television camera, said scanning means including means for generating a digital representation for identifying each scanning line, and
• means for recording said video signal for subsequent processing by a remotely located processing system.

A method for determining the cross sectional envelope defined by one or more obstacles radially disposed about a longitudinal axis parallel to an elongated path of travel comprising;

• scanning said obstacles with a rotary beam of light emitted radially about and relatively movable along said longitudinal axis to illuminate portions of said obstacles and to cause the area so illuminated to progress helically along said obstacles;
• detecting the illuminated portions of said obstacles, including the steps of aiming a television camera in a direction substantially parallel to said longitudinal axis and forming an image thereof on said television camera, said image having a shape similar to the cross section of the area between said longitudinal axis and the illuminated portions of said obstacles;
• providing an electrical analog signal corresponding to said image, said electrical analog signal being a video signal provided by said camera, and representative of the radial distance between said illuminated portions of said obstacles and said longitudinal axis;
• recording substantially all of said electrical analog signal on a record medium;
• and
• wherein the step of detecting the illuminated portions of said obstacles further includes the steps of scanning said television camera with a plurality of radial scanning lines and detecting changes in the amplitude of said video signal representative of the locations of the illuminated portions of said obstacles.