Abstract: An augmented reality, virtual reality, or other wearable apparatus comprises an eye tracking device comprising an image sensor, a lens, and one or more processors. In some embodiments, the lens comprises a marker, and the one or more processors are configured to receive an image from the image sensor, wherein the image shows the marker, determine a distance from the image sensor to the marker based on the image, and change a calibration parameter of an eye tracking algorithm based on the distance. In some embodiments, the one or more processors are configured to receive image data from the image sensor, wherein the image data corresponds to an image as observed through the lens, determine a level or pattern of pincushion distortion in the image based on the image data, and change a calibration parameter of an eye tracking algorithm based on the level or the pattern of pincushion distortion.

Abstract: A hydrocyclone (1) for separating a liquid mixture into a heavy fraction including heavy particles and alight fraction, comprising a housing (2) forming an elongated separation chamber (3) having a circumferential wall (4), abase end (5), an apex end (6), at least one inlet member (7) for supplying a liquid mixture into the separation chamber (3), at least one of the inlet member/s (7) positioned at the base end (5), a first outlet member (8) for discharging separated light fraction from the separation chamber (3) at the base end (5), a second outlet member (9) for discharging separated heavy fraction from the separation chamber (3) at the apex end (6), means (10) for supplying the liquid mixture to the separation chamber (3) via the at least one inlet member (7), so that during operation a liquid stream is generated as a helical vortex (11) about a center axis (12) in the separation chamber (3), said helical vortex (11) extending from the base end (5) to the apex end (6), a first flow deflection means arrang

Abstract: A hydrocyclone (1) for separating a liquid mixture into a heavy fraction including heavy particles and alight fraction, comprising a housing (2) forming an elongated separation chamber (3) having a circumferential wall (4), abase end (5),an apex end (6), at least one inlet member (7) for supplying a liquid mixture into the separation chamber (3), at least one of the inlet member/s(7) positioned at the base end (5), a first outlet member (8) for discharging separated light fraction from the separation chamber (3) at the base end (5), a second outlet member (9) for discharging separated heavy fraction from the separation chamber (3) at the apex end (6), means (10) for supplying the liquid mixture to the separation chamber (3) via the at least one inlet member (7), so that during operation a liquid stream is generated as a helical vortex (11) about a centre axis (12) in the separation chamber (3), said helical vortex (11) extending from the base end (5) to the apex end (6), a first flow deflection means arranged