Method and device for reading a bar code of variable orientation on a substantially motionless medium
First Claim
1. A method of reading a bar code comprised of a plurality of bars on a surface of a substantially motionless medium, said method comprising scanning at least a portion of the surface of the medium with a light beam along a raster of parallel scanning lines intersecting the bars of the code obliquely and having a fixed predetermined direction, said line succeeding each other at predetermined time and distance intervals, receiving on a photodetector a light beam reflected by the surface of the medium from the impact point of the light beam, producing a signal corresponding to the reflected light beam, detecting and recording peaks of amplitude of the produced signal of the photodetector and the positions of these peaks on each scanning line, and forming the sun of the amplitude of the peaks for each bar of the plurality of bars of the code for identifying the position of each bar of the code.
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Abstract
The present invention provides a method and apparatus for reading bar codes having variable orientations on a substantially motionless medium. A portion of the surface of the medium having a bar code in a variable orientation is scanned using a light source and a photodetector receives the beam reflected from the surface and generates signals corresponding to the scanning lines. The signal corresponds to the scanning lines and has amplitude peaks corresponding to the intersection of the bars by the light beam. The amplitude peaks and position of the peaks on the scanning lines are recorded. The sum of the amplitude peaks is formed in the positions of the bars and deduced from the sums of the peaks amplitudes.
42 Citations
18 Claims
- 1. A method of reading a bar code comprised of a plurality of bars on a surface of a substantially motionless medium, said method comprising scanning at least a portion of the surface of the medium with a light beam along a raster of parallel scanning lines intersecting the bars of the code obliquely and having a fixed predetermined direction, said line succeeding each other at predetermined time and distance intervals, receiving on a photodetector a light beam reflected by the surface of the medium from the impact point of the light beam, producing a signal corresponding to the reflected light beam, detecting and recording peaks of amplitude of the produced signal of the photodetector and the positions of these peaks on each scanning line, and forming the sun of the amplitude of the peaks for each bar of the plurality of bars of the code for identifying the position of each bar of the code.
- 10. A device for reading a bar code on a surface of a substantially motionless medium, said device comprising a light source, means for projecting a light beam from the source onto the surface of the medium, optical means for moving the light beam over at least a portion of the surface of the medium along a raster of scanning lines intersecting the bars of the code obliquely and having a predetermined direction, said scanning lines succeeding each other at predetermined time and distance intervals, optical means for transmitting the beam reflected back by the surface of the medium, photodetector means for receiving the reflected beam and generating signals corresponding to the scanning lines and having amplitude peaks corresponding to the intersection of the bars of the code by the light beam, and signal processing means comprising means for recording the amplitude peaks of the signals and their positions on the scanning lines, means for forming the sum of the amplitudes of the peaks for each bar of the plurality of bars of the code and means for deducing the positions of the bars of the code from the sums of peak amplitudes.
Specification