National Research Council of Canada

Francois Blais

J Angelo Beraldin

Marc Rioux

Michel Picard

Marc-Antoine Drouin

Jacques Domey

Generating a high definition projected illumination pattern from a substantially lower resolution digital projector array involves: selectively illuminating a connected set of pixels to produce a pixellated, high contrast edge feature, and positioning an anisotropically blurring optical element (ABOE) between a light source of the projector array and the projection. The ABOE applies an anisotropic blur pattern to pixels of the at least one connected set, to locally preferentially blur the pixel more (and preferably substantially only) in a direction of equally or more strongly illuminated pixels, and not in directions of less illuminated pixels. Preferably a contour of the connected set has no beginning or end within a periphery of the illumination plane, and has bounded curvature, permitting simple ABOEs to be used. Several images each having several or many edges can be produced using a same ABOE. The ABOE may alleviate interpixel gap effects for non-edge pixels too.

High resolution high contrast edge projection

Systems and methods for generating and optimizingD models of objects. A laser scanner is controlled by a data processing subsystem that controls the scanning and processes the data generated. From an initial model, either a raster scan of the object or an initial scan, the system scans the object multiple times, each time adjusting the laser scanner to maximize a correlation between the data generated and the model. The model is also updated using the scan data and taking into account the adjustments which were applied to the laser scanner. Other adjustments, such as those which would remove the effect of relative motion on the scan data, are also accounted for when incorporating scan data into the model. The model is recursively adjusted and optimized using previous scan data (both pre-recorded and fresh scan data) and previous adjustments. The model may be modified and adjusted using previous scan data and an Iterative Closest Point method. The method and systems may be used in uncontrolled environments where unpredictable motions and vibrations can occur. The invention may be used with scanners mounted on a robotic arm, scaffolding, unstable tripods, at the tips of booms or lifts, or the scanners may be simply held by hand.

Recursive 3D model optimization

The present invention provides a method and an apparatus for detecting a position of a light spot in a light distribution that can include stray light components (e.g. from other lasers, ambient lighting etc.) The apparatus includes a continous response position sensitive detector (CRPSD, e.g. lateral effect photo-iode) for determining a first centroid of the light distribution and a discrete response position sensitive detector (DRPSD, e.g. multiplexed array) for determining a second centroid of the light distribution within a reading window defined about the first centroid and within the light distribution. The second centroid represents the position of the light spot in the light distribution. This multiple stage approach exploits the high resolution and speed offered by traditional CRPSDs together with the accuracy under variable lighting conditions offered by traditional DRPSDs.

Position sensitive light spot detector

To provide a system for the optical ranging of a selected point on a target surface irradiated with light while avoiding false signals from other sources in a cluttered environment, the system employs a combination of the triangulation ranging technique with the Biris ranging technique, i.e. imaging onto a position sensitive photodetector through an apertured mask. This combination enables the respective equations for range that apply to the respective techniques to be combined to generate an equation that is true only for target surface points that are directly on the light beam, hence enabling rejection of false signals on the basis of those that fail to satisfy this latter equation. The system has the advantage of flexibility, in that it permits the light beam to be directed onto the target surface from a wide range of locations relative to the detector. In addition, three dimensional data on the target surface can be obtained by using at least one further light beam inclined to the first beam and a mask with more than two apertures. For many practical applications this latter arrangement avoids a need to scan the target surface relative to the detector.

Validation of optical ranging of a target surface in a cluttered

An optical system for tracking a target scans an optical beam across the target in a Lissajous pattern. The pattern has at least one portion that extends across the target. Return signals reflected from the target are used to calculate the range (and, if desired, also the intensity) of each measured point on the target (and beyond the target if some portions of the pattern miss the target), and to calculate the deviation of a reference location on the pattern, e.g. its center, from a selected location of the target. This deviation is used to correct the scan to move the reference location on the pattern towards the selected location on the target, thus tracking the target. The amplitude of the pattern can be changed to adjust the pattern on the target or to search for a target. By virtue of the range data obtainable for points on the target and on edges of the target, the system can also determine other features, such as the shape, profile, identity and attitude of the target.

Optical tracking system

A scanning device has a drive system to angularly reciprocate a rotatable mirror about an axis in a desired waveform in accordance with an excitation signal supplied by a programmable waveform generator. A position sensor generated as signal representing the actual waveform of reciprocation of the mirror, and a microprocessor determines a signal representing the error between the actual waveform and the desired waveform. The microprocessor includes a waveform optimizer that receives this error signal and delivers an excitation correction signal to the waveform generator to adjust the excitation signal from the waveform generator to cause the mirror to have an actual waveform substantially in accordance with the desired waveform.

Scanning device with waveform generator optimizer

In active range finder apparatus wherein an object to be inspected is illuminated by a laser source and light reflected by the object is detected in an imaging photosensor, a system is provided for increasing the dynamic range of the apparatus. This system provides for integrating over each of a series of measuring time periods light reflected from a window of the photosensor and hence proportional to the light received by such photosensor. When such integrated light exceeds a predetermined amount, a saturation signal is generated that immediately de-energizes the source. If this amount is not reached by the end of each period, the system is reset. The source is gradually re-energized at the commencement of each subsequent period. The virtually instantaneous de-energization and gradual re-energization combined with use of a saturation detector separate from the main photosensor ensures rapid action that is quick enough to substantially avoid saturation of such main photosensor.

Growing community of inventors

Orleans, CA, United States of America

Francois Blais