Polight Asa

Polight as

Tore Svortdal

Pierre Craen

Nicolas Tallaron

Lars Henriksen

Jacques Dumarest

Thi Kim Trinh Tran

Muhammad Asif Raza Azhar

Euan Barron

The invention relates to a method and an actuator system for determining and applying a voltage to a piezoelectric actuator (PEA) to achieve a given setpoint displacement. The method involves determining a relation d(V) between a PEA displacement measure (d) and voltage (V) and a relation tt(V) between transition time (tt) and voltage and combining the determined relations to calculate a relation d(tt) between the displacement measure and transition time during an initial calibration procedure. This relation is characteristic for the PEA, and by determining a new relation tt(V) after repeated biasing of the PEA, a compensated relation d(V) can be calculated by substituting tt(V) in the calculated d(tt). The compensated relation d(V) compensates for piezo creep effects due to the wear and can be used to determine the voltage to be applied directly, or be used in other compensation algorithms.

Determining and applying a voltage to a piezoelectric actuator

The invention relates to an electronic circuit () for controlling charging of a piezoelectric load (). The electronic circuit comprises a charge pump () configured to supply a charging current to the piezoelectric load dependent on a charge control signal (), a measurement circuit () configured to obtain a load voltage corresponding to a terminal voltage at a load terminal of the piezoelectric load, a comparator circuit () configured to compare an adjustable reference voltage with the load voltage. The electronic circuit is configured to determine the charge control signal dependent on the comparison so that the control signal controls delivery of the charging current dependent on the comparison. The electronic circuit is further configured to set the adjustable reference voltage to a target voltage (VT) and to set the adjustable reference voltage to a low limit voltage (Vlow), being lower than the target voltage, when the load voltage reaches the target voltage.

Electronic circuit for controlling charging of a piezoelectric load

The invention relates to post-processing of a digital photo to correct perspective distortion in the photo. The correction applies a digital photo of a scene and a depth map associated with the photo and comprising, for each pixel in the photo, a depth being a distance between a part of the scene in that pixel and a position of the camera at the time of acquisition. The correction is performed locally, so that the correction of any pixel in the photo depends on the depth of that pixel. The correction can be implemented as a transformation of each pixel in the original photo into a new position in a corrected photo. Afterwards, pixel values has to be calculated for the pixels in the corrected photo using the original pixel values and their new positions. The invention is particularly relevant for photos where objects or scenes involves a large magnification variation, such as selfies, close up photos, and photos when the extension of a large, object is not orthogonal to the optical axis of the camera (low/high angle shots).

Depth map based perspective correction in digital photos

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Horten, Norway

Tore Svortdal