Dual color infrared imaging systems are being developed as missile warning sensors operating within the 3μm to 5μm spectral regime. To demonstrate the sensor performance of such sensors we introduce IR test projectors which provide an optical output within the required spectral band (3µm to 5µm). A bispectral objective serves as the projection optics while also forming a part of a telescope which allows visual alignment of the projection axis with high precision, e.g. by autocollimation. A compact IR source generates the IR radiation by resistive heating with heating and decay times close to 10 ms and a large dynamic range. These characteristics are exploited for the generation of intensity sequences which simulate the IR signature of an approaching missile, accomplished by a programmable control electronics driving the IR source. Results are shown which compare the required design intensity sequence with the measured projector output intensity. As an additional design feature we have also integrated an electrically tunable Fabry-Perot filter into the test projector thus making it a tunable monochromatic IR source. This allows the measurement of the spectral sensitivity of IR sensors which is of particular importance to characterize the sensor for evaluating its performance by simulation.
Tunable femtosecond laser pulses in a large spectra range of 0.41 to 5.5 micrometers are used for noncollinear two-photon absorption in condensed matter. The spectral properties of two examples are discussed in detail: diamond of type IIa and neat water at room temperature. The generation of free carriers and results on the subsequent relaxation dynamics are presented.
Non-contact digitization with optical image sensors permits the reproduction of complex free form surface structures with high accuracy in short time. The optical sensor--based on Moire techniques combined with triangulation methods--digitizes up to 300,000 point coordinates within one view. Large objects are typically scanned in steps by controlling the sensor's position with a handling system. The partially overlapping views are connected afterwards in the computer to describe the whole model. The point cloud is exported to CAD/CAM/CAQ systems, which are doing the surface oriented processing. Today's applications range from copy-milling and surface reconstruction up to quality control and assurance. Especially the processing of the large point clouds with several millions of points needs intelligent algorithms in data organization and surface fitting. More automatic processing results in relatively low quality of the reconstructed surfaces whereas highest quality is obtained with experience and more or less interactive manipulation.