| 摘要 |
The invention presented here relates to a method for detecting the presence of objects by means of an optical sensor in a scene within the sensor's field of view. The sensor is made record images of the scene so that each individual image element is assigned a value corresponding to the detected heat radiation within the infrared wavelength range. The method is characterised in that the sensor records (1, 2) at least a pair of consecutive images of the scene, where one of the images in each pair is recorded (2) under illumination of the scene by means of a radiation source. Thereafter, a comparison image is created (4) such that each image element in the comparison image is assigned a value corresponding chiefly to a differential or quotient between the radiation values for corresponding image elements in the images recorded (2) under illumination, and the radiation values for corresponding image elements in the images recorded (1) without illumination. The image elements of the created comparison image are scanned, and the image element values that exceed a certain threshold level are marked (5) as an optical aperture within the infrared wavelength range. The invention also comprises a device for executing the method above.
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