GB1409761A - Method and apparatus for transforming points on a line into corresponding digital data signals - Google Patents

Abstract

1409761 Digitizing curves KONGSBERG VAPENFABRIKK AS 8 Jan 1973 [11 Jan 1972] 933/73 Heading H3H Apparatus and method for transforming points on a line into corresponding digital co-ordinate data signals comprises a reading head consisting of at least one row of photo-electric elements operative to generate digital signals indicative of the distance between a detected intersection of the line with the row and a reference point on the row, and means for moving the head along the line while maintaining an arbitrary intersection between the element row and the line, this means being adapted to generate position co-ordinate signals of the reference point of the row, the two digital signals being passed to an adder to determine the co-ordinates of the intersection. In a preferred embodiment the table 2 is illuminated and the head 3 is composed of two equal rows of n photodiodes forming a right-angled cross and thereby after progressing in a threaded device providing two n bit binary words indicative of the two points of intersection of the line with arms of the cross. These signals are compared at 4b and the smaller is sent via channel B to adder 5, the co-ordinates of the mid-point of the cross as determined by controller 1 being sent via 4a and channel A to the adder 5 and the co-ordinates of the intersection being recorded on a punched tape at 6. The means for moving the head may be manual or automatic utilizing the signals developed at 5 via channel C. A T.V. camera may be used as the head 3 and a row of photo-cells placed at the screen of a receiver.