Abstract: Video cameras, such as charge coupled device cameras, are used for optically making spatial measurements. For example, such cameras are used for laser beam analysis. Such cameras also have drawbacks including baseline offset error and poor signal-to-noise ratio. By adjusting the baseline so that both noise and the desired signal produce only positive digital counts, deriving a baseline offset level with only noise, and then subtracting the baseline offset level from subsequent frames Containing data representing both noise and the desired signal, the baseline offset is corrected. With the baseline offset being corrected, signal-to-noise ratio improving techniques, such as frame averaging and results averaging, can be applied to extract the desired signals which would otherwise be buried in the noise. The method and apparatus is particularly suited to laser beam performance evaluations.

Abstract: Video cameras, such as charge coupled device cameras, are used for optically making dimensional measurements of laser beams. Such cameras have drawbacks including baseline offset error, shading error, pixel-to-pixel fixed pattern offsets, and poor signal-to-noise ratio. Methods and apparatus to correct for these errors, without losing any desired signal components, wherein the baseline offset error is corrected without the loss of any signal components that may otherwise be obscured due to noise. The baseline of the signal is raised above a digitizer's zero level, an average baseline without an input signal present is determined, and then the average baseline is subtracted from the subsequently obtained signals. The subtraction process is performed such that the subsequent frames in memory retain all negative signal components, as well as positive signal components, and thus there is no loss of the desired signal.

Abstract: A tool (20) for use in the separation of elements in a building set, said elements having a face provided with coupling means which have a wall part extending transversely to the face, and which are preferably disposed in parallel with a side edge, comprises a lever (25) and a gripper means. The gripper means is disposed at one end of the lever and comprises a first jaw area (21,23) intended to tightly engage the side edge of the element, and a second jaw area (22,24) intended to tightly engage the portion of the wall part of said coupling means which faces away from said side edge. The gripper means may moreover comprise complementary coupling means for at least some of said coupling means.

Abstract: A method and system in which a programmed digital computer serving as a graphical "engine" is employed to construct an executable model for a complex system using a hierarchy of so called "Colored" Petri nets (CPN's or CP-nets). The operation of the complex system is specified in terms of a graphical net structure and formal net inscriptions, such as arc expressions and guards, which ensure development of a program, or executable model, and associated data structures, properly defining the system. Sophisticated syntax checks and other tools are provided for ensuring that the model so constructed conforms to a set of rules which guarantee valid system behavior.