Abstract: A wood grinding machine may have a vibration detection system including one or more vibration sensors. The vibration detection system may include a trip point representative of a maximum allowable level of vibration. If a vibration signal from the one or more vibration sensors exceeds the trip point, a trip protocol may be executed to automatically stop the grinding process. Related methods are also disclosed.

Abstract: A wood grinding machine may have a vibration detection system including one or more vibration sensors. The vibration detection system may include a trip point representative of a maximum allowable level of vibration. If a vibration signal from the one or more vibration sensors exceeds the trip point, a trip protocol may be executed to automatically stop the grinding process. Related methods are also disclosed.

Abstract: A method comprising: A) using a mobile device's camera to capture a first image; B) by reference to a first illumination source appearing in the first image, determining first heading information of the mobile device; C) as the mobile device moves to a second location, using one or more inertial sensors of the mobile device to extrapolate a plurality of extrapolated first candidate locations and respective first candidate headings of the mobile device; D) at the second location, using the camera to capture a second image; E) by reference to a second illumination source appearing in the second captured image, determining a plurality of second candidate locations and respective second candidate headings of the mobile device; and F) based on a comparison of the extrapolated first candidate locations and headings with the second candidate locations and headings, determining at least one estimated location and respective heading of the mobile device.

Abstract: A method comprising: A) using a mobile device's camera to capture a first image; B) by reference to a first illumination source appearing in the first image, determining first heading information of the mobile device; C) as the mobile device moves to a second location, using one or more inertial sensors of the mobile device to extrapolate a plurality of extrapolated first candidate locations and respective first candidate headings of the mobile device; D) at the second location, using the camera to capture a second image; E) by reference to a second illumination source appearing in the second captured image, determining a plurality of second candidate locations and respective second candidate headings of the mobile device; and F) based on a comparison of the extrapolated first candidate locations and headings with the second candidate locations and headings, determining at least one estimated location and respective heading of the mobile device.

Abstract: Multiple luminaires are mounted contiguously in a plane, along a straight line or following a one or two dimensional contour, but with a visible periphery between each adjacent pair. A different signal is embedded into the visible illumination emitted by each luminaire, which an image processing module can detect from one or more images captured by a camera. An angle-dependent mask is arranged to cover at least the periphery between adjacent luminaires, such that an appearance of the periphery when viewed from the environment through the mask varies as a function of viewing angle, becoming less visible at greater values of viewing angle (being the angle between a corresponding viewing direction and a normal to the plane, line or contour). The image processing module distinguishes between the different signals based on the periphery being visible when captured from less than a predetermined value of the viewing angle.

Abstract: An apparatus, method and program for receiving a coded light signal comprising a periodically repeating message repeating with a message period. A portion of the message is received in each of a plurality of frames captured by a rolling-shutter camera, with different portions being received in different frames. Using each of a discrete group of trial values of the message period, the respective trial value is used to reconstruct a respective first version of the message from the portions received in a first subset of said frames, and to reconstruct a respective second version of the message from the portions received in a second subset of said frames. For each of the trial values, there is generate a respective value of a measure of similarity between the respective reconstructed first and second versions of the message. An estimate of the message period is determined based on this.

Abstract: Multiple luminaires are mounted contiguously in a plane, along a straight line or following a one or two dimensional contour, but with a visible periphery between each adjacent pair. A different signal is embedded into the visible illumination emitted by each luminaire, which an image processing module can detect from one or more images captured by a camera. An angle-dependent mask is arranged to cover at least the periphery between adjacent luminaires, such that an appearance of the periphery when viewed from the environment through the mask varies as a function of viewing angle, becoming less visible at greater values of viewing angle (being the angle between a corresponding viewing direction and a normal to the plane, line or contour). The image processing module distinguishes between the different signals based on the periphery being visible when captured from less than a predetermined value of the viewing angle.

Abstract: An apparatus, method and program for receiving a coded light signal comprising a periodically repeating message repeating with a message period. A portion of the message is received in each of a plurality of frames captured by a rolling-shutter camera, with different portions being received in different frames. Using each of a discrete group of trial values of the message period, the respective trial value is used to reconstruct a respective first version of the message from the portions received in a first subset of said frames, and to reconstruct a respective second version of the message from the portions received in a second subset of said frames. For each of the trial values, there is generate a respective value of a measure of similarity between the respective reconstructed first and second versions of the message. An estimate of the message period is determined based on this.

Abstract: The invention relates to an apparatus, a system and a method of locating a location of a portable device using coded light, the portable device comprising an image sensor and an inertial measurement unit, the method comprising: obtaining a first image comprising the coded light source from the image sensor and substantially simultaneously obtaining orientation information indicative of the orientation of the portable device or the image sensor from the inertial measurement unit; obtaining light source specific information in the form of: an identifier that allows retrieval of a three-dimensional location of the coded light source or a three-dimensional location of the coded light source; and computing the location of the portable device or image sensor based on the orientation information, a predetermined height estimate of the portable device or image sensor and the light source specific information.

Abstract: The invention relates to an apparatus, a system and a method of locating a location of a portable device using coded light, the portable device comprising an image sensor and an inertial measurement unit, the method comprising: obtaining a first image comprising the coded light source from the image sensor and substantially simultaneously obtaining orientation information indicative of the orientation of the portable device or the image sensor from the inertial measurement unit; obtaining light source specific information in the form of: an identifier that allows retrieval of a three-dimensional location of the coded light source or a three-dimensional location of the coded light source; and computing the location of the portable device or image sensor based on the orientation information, a predetermined height estimate of the portable device or image sensor and the light source specific information.

Abstract: A method for calibrating an encoder scale having an array of marks in a first direction, includes moving the encoder scale in the first direction relative to a first encoder-type sensor, a second encoder-type sensor and a third encoder-type sensor, wherein the first encoder-type sensor and the second encoder-type sensor are fixedly spaced in the first direction at a first distance relative to each other, wherein the second encoder-type sensor and the third encoder-type sensor are fixedly spaced in the first direction at a second distance relative to each other.

Abstract: An autonomous mobile robot is configured to move across a floor area in accordance with a floor covering strategy and includes: based on a topological map of the floor area, designating a location of a current cell that is bounded by a primary boundary; executing a series of double strokes into and within the current cell, while mapping obstructive objects within the current cell onto an obstacle map; from the obstacle map, determining a secondary boundary of the current cell that encloses an area of the current cell covered by the executed double strokes, and distinguishes between secondary boundary portions thereof at which an obstructive object is located, and secondary boundary portions thereof at which no obstructive object is located; and adding the determined secondary boundary to the topological map of the floor area.

Abstract: An autonomous mobile robot configured to move across a floor area in accordance with a floor covering strategy that includes: •based on a topological map of the floor area, designating a location of a current cell that is bounded by a primary boundary (302); •executing a series of double strokes into and within the current cell, while mapping obstructive objects (306) within the current cell (300) onto an obstacle map; •from said obstacle map determining a secondary boundary (304) of the current cell, which boundary encloses an area (308) of the current cell covered by the executed double strokes, and distinguishes between secondary boundary portions thereof at which an obstructive object (306) is located, and secondary boundary portions thereof at which no obstructive object is located; and •adding the determined secondary boundary (304) to the topological map of the floor area.

Abstract: A method for calibrating an encoder scale having an array of marks in a first direction, includes moving the encoder scale in the first direction relative to a first encoder-type sensor, a second encoder-type sensor and a third encoder-type sensor, wherein the first encoder-type sensor and the second encoder-type sensor are fixedly spaced in the first direction at a first distance relative to each other, wherein the second encoder-type sensor and the third encoder-type sensor are fixedly spaced in the first direction at a second distance relative to each other.

Abstract: In an embodiment, a stage system calibration method includes moving the stage relative to an encoder grid in response to a setpoint signal and measuring a position of the stage by a sensor head cooperating with the encoder grid. The position of the stage is controlled by a stage controller. A signal representative of a difference between the setpoint signal and the position of the stage as measured by the sensor head is registered. The stage system is calibrated from the registered signal representative of the difference.

Abstract: A positioning device (11) comprises a stationary frame (2), and at least two scales (20, 30) for measuring the location of the platform with respect to the frame, the scales having mutually different pitches (P1; P2), and respective scanners (23, 33) providing respective scanner output signals (SM 1, SM2)—A controller (6) receiving both scanner output signals is capable to uniquely calculate the position (X) of the platform with respect to the frame in a measuring range (MR) that is larger than the largest of said two pitches (P1; P2).

Abstract: In an embodiment, a stage system calibration method includes moving the stage relative to an encoder grid in response to a setpoint signal and measuring a position of the stage by a sensor head cooperating with the encoder grid. The position of the stage is controlled by a stage controller. A signal representative of a difference between the setpoint signal and the position of the stage as measured by the sensor head is registered. The stage system is calibrated from the registered signal representative of the difference.

Abstract: A secondary air filter assembly that can be attached to the exhaust port of an upright vacuum cleaner is provided. The assembly includes an adapter plate that is adhered, clipped or otherwise affixed to the exhaust port, and a filter carrier that is removably attached to the base. The filter is preferably affixed as a unit to the filter carrier so that the entire filter/carrier unit can be replaced at once. The adapter base can also be used as an attachment for other accessories.

Abstract: A secondary air filter assembly that can be attached to the exhaust port of an upright vacuum cleaner is provided. The assembly includes an adapter plate that is adhered, clipped or otherwise affixed to the exhaust port, and a filter carrier that is removably attached to the base. The filter is preferably affixed as a unit to the filter carrier so that the entire filter/carrier unit can be replaced at once. The adapter base can also be used as an attachment for other accessories.

Abstract: A secondary air filter assembly that can be attached to the exhaust port of an upright vacuum cleaner is provided. The assembly includes an adapter plate that is adhered, clipped or otherwise affixed to the exhaust port, and a filter carrier that is removably attached to the base. The filter is preferably affixed as a unit to the filter carrier so that the entire filter/carrier unit can be replaced at once. The adapter base can also be used as an attachment for other accessories.