A system for external fish parasites monitoring in aquaculture, the system comprising: —a camera (52) suitable to be submerged in a sea pen suitable for containing comprising fish, the camera being arranged for capturing images of the fish; and—an electronic image processing system (86) configured for identifying external fish parasites on the fish by analyzing the captured images, wherein: —a ranging detector (54) configured for detecting the presence of fish and measuring a distance from the detector to the fish is mounted adjacent to the camera (52); and—an electronic control system (12) is arranged to control a focus of the camera (52) on the basis of the measured distance and to trigger the camera (52) when a fish has been detected within a predetermined distance range.

A system for external fish parasites monitoring in aquaculture, the system comprising: a camera (52) suitable to be submerged in a sea pen suitable for containing comprising fish, the camera being arranged for capturing images of the fish; and an electronic image processing system (86) configured for identifying external fish parasites on the fish by analyzing the captured images, wherein: a ranging detector (54) configured for detecting the presence of fish and measuring a distance from the detector to the fish is mounted adjacent to the camera (52); and an electronic control system (12) is arranged to control a focus of the camera (52) on the basis of the measured distance and to trigger the camera (52) when a fish has been detected within a predetermined distance range.

A rotation restricting structure includes a main body a rotator rotatable with respect to the main body, and a rotation restricting member which restricts rotation of the rotator, wherein the rotator includes a rotating plate which rotates with rotation of the rotator with respect to the main body, one of the rotating plate or the main body has a protrusion portion, the rotation restricting member has a contacting portion contactable with the protrusion portion and a rotational shaft which is pivotally supported by the other of the rotating plate or the main body, the protrusion portion contacts the contacting portion by rotation of the rotator, thereby the rotational angle range of the rotator being restricted, and a position of the contacting portion provided on the rotation restricting member is different from a position of the rotational shaft provided on the rotation restricting member.

The invention discloses a method for determining a starting time for a flash emitted from a flash tube of a flash apparatus. The flash apparatus comprises a triggering circuit, and a drive circuit. The method comprises the steps of measuring an electric current through and/or a voltage across an electrical component of the drive circuit, and determining the starting time for the flash based on the measured electric current and/or voltage.

An illumination apparatus includes a light source portion including a light emitter and a reflector configured to reflect light from the light emitter, a mover configured to move at least one of the light emitter and the reflector so that a relative distance between the light emitter and the reflector varies in order to change a light distribution angle of the light source portion, and a controller configured to control a position of at least one of the light emitter and the reflector via the mover based on a light emission amount of the light emitter.

A system for external fish parasites monitoring in aquaculture, the system comprising: a camera (52) suitable to be submerged in a sea pen suitable for containing comprising fish, the camera being arranged for capturing images of the fish; and an electronic image processing system (86) configured for identifying external fish parasites on the fish by analyzing the captured images, wherein: a ranging detector (54) configured for detecting the presence of fish and measuring a distance from the detector to the fish is mounted adjacent to the camera (52); and an electronic control system (12) is arranged to control a focus of the camera (52) on the basis of the measured distance and to trigger the camera (52) when a fish has been detected within a predetermined distance range.

A rotation restricting structure includes a main body a rotator rotatable with respect to the main body, and a rotation restricting member which restricts rotation of the rotator, wherein the rotator includes a rotating plate which rotates with rotation of the rotator with respect to the main body, one of the rotating plate or the main body has a protrusion portion, the rotation restricting member has a contacting portion contactable with the protrusion portion and a rotational shaft which is pivotally supported by the other of the rotating plate or the main body, the protrusion portion contacts the contacting portion by rotation of the rotator, thereby the rotational angle range of the rotator being restricted, and a position of the contacting portion provided on the rotation restricting member is different from a position of the rotational shaft provided on the rotation restricting member.

An illumination apparatus includes a light source portion including a light emitter and a reflector configured to reflect light from the light emitter, a mover configured to move at least one of the light emitter and the reflector so that a relative distance between the light emitter and the reflector varies in order to change a light distribution angle of the light source portion, and a controller configured to control a position of at least one of the light emitter and the reflector via the mover based on a light emission amount of the light emitter.

The invention discloses a method for determining a starting time for a flash emitted from a flash tube of a flash apparatus. The flash apparatus comprises a triggering circuit, and a drive circuit. The method comprises the steps of measuring an electric current through and/or a voltage across an electrical component of the drive circuit, and determining the starting time for the flash based on the measured electric current and/or voltage.

Flash tubes for photographic use, in particular, a flash tube is adapted to provide a light output adapted to FP-sync, Flat Peak. The flash tube includes a length of glass tubing enclosing a gas for use in the flash tube, a cathode inside a first end part of glass tubing and an anode inside a second end part of glass tubing. The cathode includes an element that helps to ionize the gas that is wound around the cathode, such that a spark stream starts from the upper part of the cathode and is prevented from spreading down wards on the cathode and changing the arc length during the light output adapted to FP-sync.