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Andreas Olsson

Mats Petter Pettersson

Mats Petter Petterson

An optical sensor device has an illuminating light source and an image sensor. The image sensor captures a sequence of images under exposure of light from the light source. A controller in the optical sensor device has a control output and generates an exposure time control signal on the control output. The controller includes an exposure time control loop. Each iteration of the loop includes the steps: calculating an error between a set value and an actual luminance condition value determined in a current image in the sequence of images; calculating a current exposure time as a function of the error and an exposure time calculated during the preceding iteration of the control loop; and generating the exposure time control signal on the control output based on the current exposure time. The exposure time may thereby be determined so as to yield optimum contrast in an image which is to be captured by the image sensor.

Optical sensor device and a method of controlling its exposure time

In a method for identifying objects in a digital image which is included in a sequence of images, luminance values of a current digital image are compared with at least one threshold value in order to create a current binarized image on the basis of the comparison. A quality measure for the current binarized image is also calculated, whereupon said at least one threshold value is updated on the basis of the quality measure for use in binarization of a subsequent image. The method can be realized in the form of a computer program, a computer program product, a device, and a hand-held apparatus for position determination.

Method and device for identifying objects in digital images

A method is provided for decoding data stored in a partial area of a coding pattern on a surface, based on a recorded image of the partial area. The coding pattern contains elements which each have at least two possible decoding values. The method identifies in the image a plurality of elements. The method further calculates, for each identified element, an associated value probability for each possible decoding value that the element has this decoding value. Additionally, the method performs the decoding of data based on the decoding values and the corresponding value probabilities. A device and a memory medium storing a computer program with instructions for performing such a data decoding technique are also provided.

Method and device for data decoding

Methods and apparatuses for identifying objects in a digital image include a thresholding unit and a threshold calculation unit. The thresholding unit is designed to receive the digital image and compare the luminance values of the digital image with threshold values of a threshold matrix in order to create a binary image on the basis of the comparison. The threshold calculation unit is designed to estimate, on the basis of a first and second division of a reference image which corresponds to the digital image into first and second subareas, a background luminance value for each first subarea and an object luminance value for each second subarea. The apparatuses and the methods permit quick and memory-efficient identification of the individual objects, even if the digital image contains variation in the luminance and/or sharpness.

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Lund, Sweden

Andreas Olsson