Method and apparatus for identifying an edge of an object using laser distance measurement

A scanning apparatus for identifying an edge of a target object, the scanning apparatus comprising:

• a mount;
• a laser distance measuring head;
• a sweeping unit comprising a rotary mechanism that is coupled to the mount at one end and to the laser distance measuring head at the other end;
• and
• a processor operatively coupled to the laser distance measuring head and the sweeping unit, the processor operating to:
• control the rotary mechanism to rotate the laser distance measuring head in intervals of a predetermined angle in a first direction;
• control the laser distance measuring head to direct a scan beam onto the target object at a point of incidence at each step of rotation;
• measure a distance between the laser distance measuring head and a point of incidence of the scan beam on the target object at each step of rotation;
• when a difference between a measured distance at a first step of rotation and a measured distance at a second step of rotation exceeds beyond a predetermined threshold value, identify that a first edge of the target object has occurred at a point of incidence of the scan beam corresponding to the second step of rotation, wherein the second step of rotation precedes the first step of rotation.

A method of operating a scanning apparatus comprising a laser distance measuring head for identifying an edge of a target object, the method comprising:

• directing a scan beam generated by the laser distance measuring head onto the target object at a point of incidence;
• determining a first measured distance between the laser distance measuring head and a point of incidence of the scan beam on the target object;
• rotating the laser distance measuring head by a predetermined angle in the first direction and directing a scan beam generated by the laser distance measuring head onto the target object at a point of incidence;
• determining a second measured distance between the laser distance measuring head and a point of incidence of the scan beam on the target object;
• determining a difference between the second measured distance and the first measured distance;
• when the difference exceeds a predetermined threshold value, identifying that a first edge of the target object has occurred at the point of incidence of the scan beam corresponding to the first measured distance;
• and
• when the difference is less than the predetermined threshold value, setting the first measured distance to have value of the second measured distance, and repeating the operations of rotating the laser distance measuring head by the predetermined angle in the first direction, determining a second measured distance between the laser distance measuring head and a point of incidence of the scan beam on the target object, and determining a difference between the second measured distance and the first measured distance until a first edge of the target object is identified.