Abstract:
The present invention refers to a an optical system 100 comprising a light source 10 comprising a plurality of light emitting elements 11, mounted on the same substrate or chip board in thermal contact with each other such as to enable thermic conduction and heat transfer between the LEEs, wherein the system is switchable between light source modes in which different light emitting elements or a different number of light emitting elements is switched in an on mode and in a down mode respectively. In particular in all light source modes, one or more light emitting elements, preferably those with longer expected lifetime, remain in the on mode, while one or more light emitting elements, preferably those with shorter expected lifetime, may be switched in the down mode.
Abstract:
A method and a system for spectral calibration of a remote sensing sensor and a synthetic target having a tunable spectral composition are described. The system or synthetic target includes a plurality of reflective mirrors arranged to reflect radiation from a source of radiation onto a remotely located radiation sensor. A first mirror in the plurality of mirrors is configured to reflect a first portion of the radiation in a first wavelength toward the remotely located radiation sensor. A second mirror in the plurality of mirrors is configured to reflect a second portion of the radiation in a second wavelength different from the first wavelength toward the remotely located radiation sensor. The first portion of the radiation and the second portion of the radiation can be selected to calibrate the remotely located radiation sensor so as to provide a quantitative spectral relationship between the radiation detected at the remotely located sensor and the radiation reflected by the plurality of mirrors.
Abstract:
Disclosed is a method for correcting the temperature sensitivity of the amount of light L emitted by a light emitting diode (LED) and measured in a light detector, said LED being operated in a pulsed mode with an essentially constant pulse duration tP. According to the inventive method, a predetermined parameter X that has a predetermined ratio to the temperature T of the LED is used while a corrective factor K is determined from said parameter X, preferably using a calibration table, most preferably a closed, predetermined function, with the aid of which the measured emitted amount of light L is corrected by the temperature-dependent variations of the emitted amount of light. The parameter X is determined from at least two output signals of the LED which are correlated in a predetermined manner.
Abstract:
The invention relates to a calibration radiation source comprising the following: a housing (2) having an opening (12), a carrier (22) accommodated in the housing (2), a semiconductor radiation source (18) carried by the carrier (22) and serving for generating a light beam, and an exit opening mount element (14) having a light exit opening (15), which is arranged in the region of the opening (12) and through which the light beam generated by the semiconductor radiation source (18) is emitted towards the outside from the housing (2). The exit opening mount element (14) is fixed to the carrier (22) of the semiconductor radiation source (18) in a manner decoupled from the housing (2).
Abstract:
There is disclosed improved apparatus and methods for detection of shape, size and intrinsic fluorescence properties of a fluid borne particle wherein the apparatus comprises a laser, two light sources, two detectors, and optionally a third detector. The apparatus is particularly suitable for detection of airborne biological particles.
Abstract:
Die Erfindung betrifft eine Vorrichtung zur mehrstufigen Dämpfung einfallender Strahlungsenergie, insbesondere zur Kalibrierung von bildgestützten Instrumenten zur Fernerkundung der Erde. Die Aufgabe, eine neue Möglichkeit zur definierten mehrstufigen Dämpfung einer Konstantlichtquelle zu finden, die mit einfachen Mitteln eine zuverlässige und langzeitstabile reproduzierbare Einstellung von definierten Strahlungszuständen, insbesondere für die Mehrpunktkalibrierung von Sensoren, gestattet, wird erfindungsgemäß gelöst, indem Filter mit unterschiedlicher Transmission als begrenzte Anzahl von Filterplatten (3; 31, 32) mit beliebig hergestellter Transmissionsstruktur in einem Lichtschacht (2), der einen Kalibrierstrahlengang darstellt, hintereinander aperturfüllend einsetzbar sind, so dass sie jeweils einzeln und in Kombinationen miteinander eine Anzahl von definierten, reproduzierbar abgestuften Dämpfungszuständen des Lichts einer Referenzstrahlungsquelle (1), die die Anzahl der Filterplatten (3; 31, 32) übersteigt, erzeugen.
Abstract:
A spectrophotometer including a light source (1) operative to emit a beam of light (15), an optical system for directing the light beam (15) to a sample (8) to be analysed, and a detector (9) which detects the intensity of the light beam after that beam interacrs with the sample (8). The light source (1) is operative to emit bursts of light separated by an interval during which no light is emitted. By way of example, a xenon tube may be used for that purpose. The spectrophotometer measures the intensity of the light beam generated by each burst of light after that beam interacts with the sample. Each such light beam may be divided into first and second parts (5 and 4) prior to interaction with the sample (8), and the optical system is arranged to direct the first part (5) to the sample (8) and to direct the second part (4) to a second detector (7) for conducting a reference measurement. A dark signal measurement may be conducted immediately before or after each burst of light.
Abstract:
An imaging system is disclosed comprising an illuminator (1) which produces illumination of any desired pure wavelength or of an selected mixture of pure wavelengths simultaneously, which illuminates a sample without spatio-spectral artifacts using illumination optics designed for that purpose; imaging optics (11a-11j), which form an image of the sample at a detector or viewing port; and a detector. This enables imaging the complete spectral image cube for a sample by taking sequential images while illuminating with a series of pure wavelengths, with greater ease and economy than by means of tunable filters (12a-12j), interferometers and the like. It further enables imaging while the sample is illuminated with a precisely controlled mixture of illuminant wavelengths, so that the image presented to the detector is a linear superposition of the sample properties at many wavelengths.
Abstract:
Display systems (100) that utilize digital micro-mirror device (DMD) technology are finding wide application in the areas of projection systems for color display. The common name for such systems is digital light processing projection systems or DLP projection systems. The systems and methods described herein utilize the non-imaging light to monitor and calibrate the projected image since the high levels of illumination and extreme temperatures of the imaging light require careful attention to the manner of light collection. Light collection is accomplished in a waste gate area (102) by a light collector, e.g., an optical fiber mat, and the collected light is communicated to an associated sensor. The technique is non-invasive and may be applied to existing designs with minimal modification.