Abstract: Apparatus for reading optically a scene made up of symbols on a transparent medium comprises a transparent flat plate on which the scene is supported. An illumination system on one side of this plate illuminates at least part of the scene. An optical reader device on the opposite side of the plate incorporates an optical sensor. A pneumatic skid is moved over the opposite side of the plate and has a recess in its surface facing the plate in which the sensor is accommodated. Thus the scene is scanned by the sensor as the skid is moved over the plate.

Abstract: A two-dimensional pattern made up of primary and secondary shapes having different levels of contrast, e.g. a printed circuit card, is visually inspected by means of a line-by-line scan, e.g. using a beam of light. A data structure or "file" is built up representative of the current scan line and is compared with a similar file representative of the accumulated scan history so far. The accumulated history file is then updated, the next line is scanned, and the sequence repeats. Allowable changes in shape between scan lines can be coded in the form of multiple-entry digital tables. Non-allowable changes cause alarms to be generated. Allowable changes can easily be altered by downloading a new set of tables, thereby enabling the method to be readily adapted to inspecting different types of object. The method is suitable for implementation by hard-wired logic for high-speed real-time operation.

Abstract: Patterns (f) in a scene (S) are analyzed in order to automatically distinguish symmetrical perceptible areas (P) in the pattern (f), even if said symmetrical perceptible areas (P) are intersected by auxiliary patterns (F). A digitized image (Id) is used, and a test point (cO) located inside the digitized pattern (fd) is used as a starting point. A sequence of circles of increasing diameter is drawn around the test point. Whenever one such circle (CO.sup.i) intersects the digitized pattern (fd) a new center (c1) is chosen, offset from the preceding center (c0) in a direction going away from the point of intersection. By iteration, a sequence of test points (cn) is thus constructed which, for a symmetrical pattern, converges on its center of symmetry (c).

Abstract: Logs which have previously been de-limbed are placed onto and removed from a loading deck one at a time and delivered to an aligning trough or mechanism where one end of all logs are moved to a common point. The logs are then conveyed one at a time by a feed conveyor in a direction transverse to the longitudinal axis of the logs and presented to a sawing mechanism where each log is sawed simultaneously into a plurality of shorter firewood pieces. The sawing mechanism includes a plurality of circular saws spaced longitudinally along a common axis which is, in turn, spaced above the level of the feed conveyor and extends parallel to the longitudinal axis of the logs. Each saw is individually mounted for ease of removal and adjustment. A spring device urges the log downwardly, while lugs on the feed conveyor at the same time urge the log forwardly through the sawing mechanism.