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Randomized Hough Transform 2: Rototranslations

Here I briefly explained how the RHT works, with reference to a very simple case (finding the directions of rows and columns of a grid). Now I’ll spend some words on a more complex application. When scanning the surface of … Continue reading

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Gaze tracking as a novel input method

Smartphones and tablets usually have a camera on their back, to take photographs, and a frontal camera for videoconferencing.       In a recent model (Samsung Galaxy S4) the frontal camera can be used as an input device too: … Continue reading

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Randomized Hough Transform

The Hough transform can be used to extract shapes from images. As an example, consider a binary image (pixel values can be only 0 – black, belonging to the background – or 1 – white, belonging to the shape) from … Continue reading

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Reconstruction of 3D points from images in a calibrated binocular system

In a binocular system one can write and where is an object point in homogeneous coordinates in mm (*), and  are its image points in homogeneous coordinates in pixels, and  are the projection matrices of the two cameras, and are … Continue reading

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Vanishing points in presence of noise

Most self-calibration algorithms require a prior knowledge of the camera calibration matrix ; as an instance, you need it to normalize the image points as and therefore fit the essential matrix . With most commercial cameras it is safe to … Continue reading

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Forward bundle adjustment/2

Some more notes about my implementation of the forward bundle adjustment algorithm (see my previous post). Monocular systems. According to Mitchell, Warren, McKinnon and Upcroft, the original algorithm does not work with monocular systems, due to a limitation of the sub-algorithm used … Continue reading

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Forward bundle adjustment

In a recent post I wrote about the essential matrix. If the internal parameters (pixel pitch, focal length, principal point) of both cameras in a stereo rig are known, the essential matrix can be obtained from at least eight couples … Continue reading

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