Abstract: A device for determining the position of a light source, including an optical mask with a periodic pattern casting a shadow on an imager placed at a multiple of the Talbot distance or at a fraction of the Talbot distance.

Abstract: A positioning system, in particular, six-dimensions positioning system of a shadow sensor with respect to a constellation of light sources is provided. The sensor can be a shadow sensor and has a mask and a 2D imager. By recording the shadow of the mask cast by each light source on the imager, and by properly multiplexing the light sources, the system can compute the 6D position of the shadow sensor with respect to the constellation of light sources. This computation is based, in part, on treating the shadow of the mask cast on the imager as the equivalent of the projection of light in a pinhole or projective camera. In one embodiment, the system is applied in a surgical domain. In another embodiment, the system is rapidly deployed.

Abstract: A positioning system, in particular, six-dimensions positioning system of a shadow sensor with respect to a constellation of light sources is provided. The sensor can be a shadow sensor and has a mask and a 2D imager. By recording the shadow of the mask cast by each light source on the imager, and by properly multiplexing the light sources, the system can compute the 6D position of the shadow sensor with respect to the constellation of light sources. This computation is based, in part, on treating the shadow of the mask cast on the imager as the equivalent of the projection of light in a pinhole or projective camera. In one embodiment, the system is applied in a surgical domain. In another embodiment, the system is rapidly deployed.

Abstract: A position measurement system for determining 2D displacement or position of a mobile element with respect to a reference frame, including: a point light; an optical mask having transparent and opaque areas defining a repetitive pattern on at least one side of its surfaces; an imager, fixed to a mobile element, including integrated electronic circuits allowing detection, computing and analyzing of a shadow projected by the optical mask. The position measurement system includes an optical diffuser plate between the light source and the mask. The imager, mask and diffuser plate form an assembly so as to produce a light spot created by the scattering of the incident light beam emitted by the light source on the diffuser plate. The mask positioned between the diffuser plate and imager, produces a shadow on the imager, allowing to compute and provide 2D position of the mobile element relative to the fixed reference frame.

Abstract: A system measures the position of a light source in space using an imager and transparent surface with a pattern on top. The pattern consists of a repetitive pattern and a distinctive element. The system achieves sub-micron precision. It also handles the measurement of several light sources simultaneously, and the measurement of the position of a retroreflector instead of the light.

Abstract: A position measurement system for determining 2D displacement or position of a mobile element with respect to a reference frame, including: a point light; an optical mask having transparent and opaque areas defining a repetitive pattern on at least one side of its surfaces; an imager, fixed to a mobile element, including integrated electronic circuits allowing detection, computing and analyzing of a shadow projected by the optical mask. The position measurement system includes an optical diffuser plate between the light source and the mask. The imager, mask and diffuser plate form an assembly so as to produce a light spot created by the scattering of the incident light beam emitted by the light source on the diffuser plate. The mask positioned between the diffuser plate and imager, produces a shadow on the imager, allowing to compute and provide 2D position of the mobile element relative to the fixed reference frame.

Abstract: A system measures the position of a light source in space using an imager and transparent surface with a pattern on top. The pattern consists of a repetitive pattern and a distinctive element. The system achieves sub-micron precision. It also handles the measurement of several light sources simultaneously, and the measurement of the position of a retroreflector instead of the light.

Abstract: The invention relates to a method of calculating the local contrast at each pixel (PC) in a network (Mp) of photosensitive pixels which are arranged in at least one dimension (x, y). The inventive method consists in, during successive image acquisition cycles, producing a signal which is representative of the local luminance at each pixel, said luminance-representative signals being integrated values of luminance values sensed by the respective pixels (pC, pG, pD, pH, pB). The inventive method consists in: sampling the integrated values of the signals representing the luminance values at the pixels adjacent (pG, pD, pH, pB) to a considered pixel (pC), said sampling taking place at an instant in the cycle when the integrated value of the luminance at the considered pixel (pC) is equal to a pre-determined reference value; and determining the local contrast at the considered pixel (pC) on the basis of values thus sampled.

Abstract: A method of detecting relative movement between a scene from which radiation emanates and a matrix of pixels observing the scene and capable of detecting the radiation, each pixel of the matrix measuring contrast vector information representative of the observed scene monitors the evolution of the contrast vector information in each pixel of the matrix During a first time interval, it detects among the pixels the pixel whose magnitude vector information value is greater than the magnitude vector information value of the adjacent pixels. During a second time interval consecutive to the first time interval it detects if the magnitude vector information of the pixel whose value was at a maximum during the first time interval has decreased. It generates output signals representative of the relative movement if a decrease is detected.

Abstract: The invention relates to a method of calculating the local contrast at each pixel (PC) in a network (Mp) of photosensitive pixels which are arranged in at least one dimension (x, y). The inventive method consists in, during successive image acquisition cycles, producing a signal which is representative of the local luminance at each pixel, said luminance-representative signals being integrated values of luminance values sensed by the respective pixels (pC, pG, pD, pH, pB). The inventive method consists in: sampling the integrated values of the signals representing the luminance values at the pixels adjacent (pG, pD, pH, pB) to a considered pixel (pC), said sampling taking place at an instant in the cycle when the integrated value of the luminance at the considered pixel (pC) is equal to a pre-determined reference value; and determining the local contrast at the considered pixel (pC) on the basis of values thus sampled.

Abstract: A method of detecting relative movement between a scene from which radiation emanates and a matrix of pixels observing the scene and capable of detecting the radiation, each pixel of the matrix measuring contrast vector information representative of the observed scene monitors the evolution of the contrast vector information in each pixel of the matrix During a first time interval, it detects among the pixels the pixel whose magnitude vector information value is greater than the magnitude vector information value of the adjacent pixels. During a second time interval consecutive to the first time interval it detects if the magnitude vector information of the pixel whose value was at a maximum during the first time interval has decreased. It generates output signals representative of the relative movement if a decrease is detected.