Bottle inspection apparatus

Apparatus for inspecting the side walls of transparent or translucent bottles for the detection of dirt or foreign bodies therein while the bottles are being conveyed to bottle filling apparatus, comprising a conveyor for moving the bottles to be inspected, supported only by their bases resting on the conveyor, through an inspection station, means for driving said conveyor continuously at a selected linear speed, means for delivering successive bottles to said conveyor in spaced apart relation and at a speed of movement equal to the linear speed of the conveyor, means for diffusely illuminating the side walls of a bottle as it moves through the inspection station, means for projecting, while a bottle is so illuminated, a plurality of images of the side walls of the bottle, as viewed from at least two different directions in plan, on to at least one integrated circuit device comprising an array of photo-diodes arranged in a plurality of rows with a plurality of diodes in each row in combination with array scanner means cyclically to scan the array and interrogate each diode in turn, along each row in turn, to provide a video signal comprising a sequence of electrical signals corresponding to the light energy each diode has received, means synchronised with said array scanner means to generate gating pulses of the desired length for each row, and means for feeding said video signal to electric circuit means including means for differentiating said video signal and gate means controlled by said gating pulses for gating-out unwanted signals outside the limits of the images of the side walls of the bottle to be inspected whereby to generate differentiated signal pulses representative of dirt or foreign bodies in the bottle, said electric circuit means also including means for inverting the differentiated signal pulses of one polarity so that all signal pulses are of the same polarity.