Latent image barcode

A latent image bar code (LIBC) reader located in relation to a filmstrip transport path for reading bar code data imprinted on the edge of a filmstrip. The LIBC reader comprises at least one illumination source and linear array of CCD elements extending transversely from one side wall of the film transport path. When suitably clocked out, each CCD element provides a signal dependent on the intensity of the illumination received. The output signals from the CCD array are processed to detect an edge of the filmstrip by the contrast in signal amplitude due to attenuation of the transmitted light intensity by the filmstrip substrate at the junction of the filmstrip with a gap separating the filmstrip edge and the side wall of the transport path. Once the edge of the filmstrip is identified, the output signals of segments of the CCD array aligned with the clock and data tracks of the bar code are sampled, digitized and compared to reference signals to discern the bar code pattern in the clock and data tracks. The bounds of the segments of CCD elements sampled are preferably set as sample time boundary functions triggered on edge detection.

References

* http://www.freepatentsonline.com/5448049.html - Patent for Latent image barcode.