Axis Ab

Digital Imaging Systems Gmbh

Anders Johannesson

Stefan Lundberg

Markus Skans

Jonas Hjelmström

Jiandan Chen

Per Kannermark

Jonas Hjelmstrom

Joakim Baltsen

Ingemar Larsson

Joakim Baltsén

Wilfried Rakow

A method of monitoring a scene by a camera () comprises marking a part () of the scene with light having a predefined spectral content and a spatial verification pattern. An analysis image is captured of the scene by a sensor sensitive to the predefined spectral content. The analysis image is segmented based on the predefined spectral content, to find a candidate image region. A spatial pattern is detected in the candidate image region, and a characteristic of the detected spatial pattern is compared to a corresponding characteristic of the spatial verification pattern. If the characteristics match, the candidate image region is identified as a verified image region corresponding to the marked part () of the scene. Image data representing the scene is obtained, and image data corresponding to the verified image region is processed in a first manner, and remaining image data is processed in a second manner.

Monitoring method and camera

The present invention relates to a method () for reducing stray light in an output image of a scene, said method comprising; providing () a camera () comprising a lens assembly (), providing () an aperture unit () having an aperture gate () in an aperture plane being orthogonal to an optical axis (OA) of said lens assembly (), said aperture gate () being adjustable in said aperture plane, acquiring (), by means of said camera (), a plurality of images of said scene, wherein each image of said plurality of images is acquired using an unique aperture gate setting, wherein each of said unique aperture gate settings correspond to a unique combination of a position and a shape of said aperture gate () in said aperture plane, analyzing () said plurality of images for generating data pertaining to a difference in stray light content with respect to said plurality of images, and producing () said output image based on said data pertaining to said difference in stray light content.

Method, lens assembly and camera for reducing stray light

An image acquisition device and a method for capturing image data is disclosed. The method comprises exposing an image sensor to light from a scene, selecting substantially all rows of sensor pixels in an image sensor in a substantially random order, starting an exposure period for each row of sensor pixels in the image sensor in the order the rows were selected, buffering the rows of sensor pixels comprised in an image frame until all rows of the image frame have registered image data for the presently captured image frame, and outputting image data representing the image frame by outputting image data from each row of sensor pixels.

Device and a method for image acquisition

There is provided a method for determining the reliability of a fault detection of a camera in a camera system. According to the method data relating to environmental conditions are received () and compared to accessed () criteria relating to environmental conditions external to the camera and affecting the reliability of the fault detection test. If the received data complies with the criteria it is determined () that the fault detection test gives a reliable result. This is advantageous in that false fault detection tests may be identified.

Reliability determination of camera fault detection tests

A method for determining a tilt of an image sensor surface plane in a camera in relation to a lens reference plane of the camera includes sending light onto the image sensor, receiving light reflected from the image sensor, identifying an interference pattern in the reflected light, identifying a feature of the interference pattern, and determining the tilt of the image sensor surface plane based on a position of the feature identified in the interference pattern.

Method for determining the tilt of an image sensor

A method used for the compensation of vignetting in digital cameras has been achieved. The compensation for vignetting is done in two steps. The first step is done during production of the camera unit and involves taking and analyzing an image of a test screen, preferably a gray test screen. This results in a set of e.g. 5&#xd7;5 coefficients describing a polynomial surface. The second step is done for each image that is taken by the camera and involves calculating and applying a gain-table based on polynomial coefficients to all pixels of the image to compensate vignetting.

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Hollviken, Sweden

Anders Johannesson