Method and apparatus for self-correcting, direct sensing coincidence sensor for optical rangefinders

A direct sensing coincidence sensor device comprising:

• spatial referencing means, for producing first and second channel marker beams of radiation with a mutual and laterally stable angular relationship;
• first and second entrance means for receiving said first and second channel marker beams of radiation from said spatial referencing means, and for receiving first and second channel target beams of radiation from a target object of interest;
• channel merging/splitting means for merging and splitting said first and second channel marker beams, and for merging and splitting said first and second channel merging/splitting means;
• photodetector means, for sensing the separation of first and second channel reference marker images formed from said first and second channel marker beams after exiting said channel merging/splitting means;
• means for sensing the separation of first and second channel target scene images formed from said first and second channel target beams exiting said channel merging/splitting means;
• and
• scene reduction means whereby the effect on said photodetector means of at least one of said first and second channel target scene images is reduced relative to at least one of said first and second channel reference marker images.

A direct sensing coincidence sensor device comprising:

• spatial referencing means, for producing first and second channel marker beams of radiation with a mutual and laterally stable angular relationship;
• first and second entrance means for receiving said first and second channel marker beams of radiation from said spatial referencing means, and for receiving first and second channel target beams of radiation from a target object of interest;
• channel merging/splitting means for merging and splitting said first and second channel marker beams, and for reflecting said first and second channel target beams of radiation;
• reflecting means for directing said marker beam radiation and said target beam radiation to said channel merging/splitting means;
• first and second photodetector means, whereby at least one of said first and second photodetector means senses the separation of both first and second channel marker images formed from said first and second channel marker beams, and said first photodetector means in conjunction with said second photodetector means senses the separation of at least one of said first and second channel marker images formed from at least one of said split first and second channel marker beams, and whereby said first photodetector means in conjunction with said second photodetector means senses the separation of first and second channel target scene images formed from said first and second channel target beams.

A method for determining a parameter relating to a target object of interest using a direct sensing coincidence sensor device, comprising the steps of:

• sighting said target object of interest;
• producing first and second channel market beams of radiation;
• receiving first and second channel target beams of radiation from said target object of interest;
• directing said first and second channel marker beams and said first and second channel target beams along a desired path;
• splitting each of said first and second channel market beams and reflecting each of said first and second channel target beams at a common location;
• coupling at least one of said split first channel marker beams with at least one of said split second channel marker beams at said common location;
• forming first and second channel reference marker images of said at least one of said coupled split first and second channel marker beams onto at least one photodetector means;
• forming reference marker images of at least one of said split first and second channel marker beams onto said first photodetector means and onto a second photodetector means;
• forming said first channel target scene images of said first channel reflected target beam onto one of said first and second photodetector means, and forming said second channel target scene images of said second channel reflected target beam onto the other of said first and second photodetector means;
• detecting information relating to the relative separation of said reference marker images, and relating to the relative separation of said target scene images on said first and second photodetector means.