Pinfall detector using video camera

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG.
1 is a schematic diagram of two bowling lanes 100 and 105 viewed from a overhead position.
Each of lanes 100 and 105 has a conventional pin deck with a set of pins 110 and 115 located at the end of the lane.
FIG.
1 shows three illustrative camera positions which could be used to view pin set 110.
For example, the camera may be positioned in front of the pin deck (attached to the pin spotter equipment or to another convenient location) at position 120.
Alternatively, the camera may illustratively be positioned at a position 130 between the gutter areas 125 and 140 as shown by camera position 130 or at an approach area to the side of the lane as shown by camera position 145.
Generally, only one camera will be necessary for each lane.
However, in some situations additional cameras may be necessary to insure that all pins can be readily detected.
The second camera may be located in such a position that it views the pins from a different perspective to eliminate hidden pins.
The position of the camera or cameras can be adapted to existing architecture and practical considerations, the only requirement being that the camera have a clear view of all pins.
In order to obtain an adequate pin image, an appropriate camera lens must be used with a focal length that ensures an undistorted view of the pin deck from the camera placement position.
The analog video signal comprising the pin image developed by the camera is provided to video processing circuitry which will be hereinafter described in detail.
In general, a video "snapshot" is taken of the pins.
That is, the camera signal is gated on for a brief interval of time (approximately one frame time or 16 milliseconds).
The video image signals are then converted to 4-bit digital words by a conventional "flash" type analog-to-digital converter and stored in a random access memory (RAM).
The digital pixel values in the RAM are subsequently processed (as determined below) to determine the number of pins that remain standing