The Secretary of State for Defence

Sean Michael Tsi-Ong Tipper

Christopher David Burgess

Techniques for detecting pulsed radiation. A CMOS sensor array being irradiated across at least a portion of the array with pulsed radiation is addressed using a rolling shutter operation. The sensor array is read to extract the integrated energy from each sensor element and convert the integrated energy into a pixel value for a pixel in a radiation image. A pulse detection operation is then applied to the radiation image to obtain a pulse repetition frequency of the pulsed radiation. The pulse detection operation includes extracting a beat signal, calculating a beat frequency and peak to trough ratio from the beat signal, and determining the pulse repetition frequency therefrom. Particularly suited to the technical field of pulsed laser detection. Also relates to a pulse detector for the same.

Computer implemented method for detecting pulsed radiation

A method of detecting pulsed radiation comprising the steps of irradiating at least a portion of an array of sensor elements with pulsed radiation (); addressing the array using a rolling shutter operation (); reading the array to obtain a radiation image (); and then applying a pulse detection operation () to the radiation image. The rolling shutter operation () is configured to address each element line of the array for a predetermined integration period. The predetermined integration period being calculated using an integration period function, itself a function of an anticipated pulse repetition interval of the pulsed radiation. The method and apparatus for the same enable low cost camera arrays to be used for pulse detection and for wider application in the field of low cost communications.

Method and apparatus for detecting pulsed radiation

Video camera or video camera module, comprising an RGB image sensor, a computer processor adapted to perform pre-processing followed by video compression, and a dazzle detector, characterised in responding to dazzle in one colour channel by reducing values in that colour channel prior to compressing the video data. This has the advantage that in the event of laser dazzle that is specific to a colour channel, the compressed video data generated will retain more detail from the other colour channels compared to a conventional camera.

Dazzle resilient video camera or video camera module

A laser detector apparatus () is provided, where a pixel array () is arranged behind a lens arrangement () such that distant objects () (in general, those at infinity) are out of focus at the pixel array. The image from the pixel array is evaluated by a computer processor () to detect such out of focus images which will be of a known size and shape (generally circular spots of known width). This can enable distant laser threats to be readily distinguished from nearby bright objects (), whilst also protecting the pixel array from powerful laser sources (because the laser energy is not focussed to a point, on the pixel array it is less likely to damage the pixel array). It can also enable the wavelength of the laser to be accurately determined from the ratio of colours in the image of the laser spot, because it will typically not be a saturated image. The apparatus and method are particularly suitable for identifying and distinguishing laser sources across a wide range of brightnesses, and is also suitable for detecting and distinguishing multiple laser sources.

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Salisbury, United Kingdom

Sean Michael Tsi-Ong Tipper