Abstract: A method and apparatus for the correction of the image values of faulty sensors of an optoelectronic transducer comprising a plurality of sensor elements. In order to avoid errors at light/dark transitions in the scanned original, the erroneous image value of a faulty sensor element is fully corrected in areas of the original having nearly constant brightness values and is only slightly corrected in regions of light/dark transitions (contours) in the original. In order to achieve this, the erroneous image value of a faulty sensor element is replaced by the image value of the sensor element neighboring the faulty sensor element that comprises the least difference from the erroneous image value in terms of amount. Alternatively, the erroneous image value is replaced by the median value calculated from the image value of the faulty sensor element and from the image values of the sensor elements neighboring the faulty sensor element.

Abstract: A method and apparatus for setting sharpness of an optical image system by step-by-step adjustment of the distance between a subject and an objective until a maximum is achieved for respectively identified sharpness values of the objective.

Abstract: A method and an apparatus for setting the sharpness of an optical imaging system by step-by-step adjustment of the distance between a subject and an objective and by evaluating the sharpness values identified for the individual distances. First, the sharpness values (S) for two distances (R) modified proceeding from a prescribed distance (Ro) by a respective step width in both adjustment directions are identified and the best sharpness value is determined by comparing these sharpness values (S) to the sharpness value (So) for the prescribed distance (Ro). Respectively two distance points (R1 through R4) having defined step widths proceeding from the prescribed distance (Ro) are then identified in an allowed range of adjustment (VS) and the appertaining sharpness values (S1 through S4) are identified.

Abstract: A method and an arrangement for producing rastered printing forms having rasters with arbitrary raster angles on the basis of at least one recording beam moving across a recording medium. The recording beam is switched on or, respectively, off corresponding to the size and position of raster dots. A switch signal for the recording beam is generated by a signal comparison between the image signal, which represents the tonal values of an original, and stored raster thresholds, which represent the periodic basic structure of a raster mesh. Coordinate increments corresponding to the proceeding recording are accumulated dependent on the screen angle to form coordinate values. A plurality of most significant binary places of the coordinate values form addresses for reading out the stored raster thresholds. Random numbers are superimposed on the coordinate values.