Charge coupled device pulse discriminator

Apparatus for detecting range from a reference point to an object using light energy, said apparatus comprising:

• means for emitting a pulse of light energy at a predetermined time;
• means for accumulating a first photocharge from said light energy pulse and background illumination incident on the accumulating means during a first sample time, and for accumulating a second photocharge from said background illumination incident on the accumulating means during a second sample time;
• means for controlling exposure of the accumulating means to said light energy pulse by enabling said accumulating means to detect said light energy pulse at a predetermined sample time determined by detected emission of said light energy pulse;
• and
• means for generating a differential output proportional to a difference between said first photocharge and said second photocharge.

Method for detecting light energy comprising the steps of:

• accumulating a first photocharge from a pulse of light energy and background illumination incident on an accumulating means during a first sample time, exposure of said accumulating means being controlled in response to detected emission of said light energy pulse;
• transferring said accumulated first photocharge to a column of photocharge storage elements of said accumulating means upon completion of said first sample time;
• summing photocharge from said column of photocharge storage elements;
• transferring said summed photocharge to a storage means;
• accumulating a second photocharge from said background illumination incident on the accumulating means during a second sample time;
• and
• generating a differential output proportional to a difference between said summed photocharge and said second photocharge.