Apparatus for recording and reading an image on a medium and detecting errors and media defects

摘要

Apparatus is disclosed for recording and reading a color image formed on a receiving medium such as a film coated with a blue metastable colloidal silver. Upon application of heat to selected areas of the coating, the blue silver turns yellow to form an image. In a record mode, a modulated beam from a diode laser is scanned onto the receiving medium to form an image. In a read mode, a diode laser beam containing two different wavelengths of radiation is scanned across an image on the recording medium. In order to detect errors in the image, a detector senses the two wavelengths at each pixel and produces signals indicative of the densities of the yellow and blue in the pixel. Signal processing means is adapted to determine valid data points from the two signals.