An electronic device includes at least one optical lens assembly. The optical lens assembly includes four lens elements, and the four lens elements are, in order from an outside to an inside, a first lens element, a second lens element, a third lens element and a fourth lens element. The first lens element has an outside surface being convex in a paraxial region thereof. The second lens element has an inside surface being convex in a paraxial region thereof. The fourth lens element has an inside surface being concave in a paraxial region thereof, wherein at least one of an outside surface and the inside surface of the fourth lens element includes at least one critical point in an off-axis region thereof.

An optical detector(110) is disclosed, comprising: at least one optical sensor(122) adapted to detect a light beam(120) and to generate at least one sensor signal, wherein the optical sensor(122) has at least one sensor region(124), wherein the sensor signal of the optical sensor(122) exhibits a non-linear dependency on an illumination of the sensor region(124) by the light beam (120) with respect to a total power of the illumination; at least one image sensor(128) being a pixelated sensor comprising a pixel matrix(174) of image pixels(176), wherein the image pixels(176) are adapted to detect the light beam(120) and to generate at least one image signal, wherein the image signal exhibits a linear dependency on the illumination of the image pixels(176) by the light beam(1,6) with respect to the total power of the illumination; and at least one evaluation device(132), the evaluation device(132) being adapted to evaluate the sensor signal and the image signal. In a particularly preferred embodiment, the non-linear dependency of the sensor signal on the total power of the illumination of the optical sensor(122) is expressible by a non-linear function comprising a linear part and a non-linear part, wherein the evaluation device(132) is adapted to determine the linear part and/or the non-linear part of the non-linear function by evaluating both the sensor signal and the image signal. Herein, the evaluation device(132), preferably, comprises a processing circuit(136) being adapted to provide a difference between the sensor signal and the image signal for determining the non-linear part of the non-linear function.

A method for attaching camera filters and other light transmissive elements using flexural rigidity. A flexion arm enables coupling with cameras and other devices in areas non-proximate to a lens. A frame conjoined with the flexion arm enables attachment of the camera filter to a camera lens or lens housing.

A method for attaching camera filters and other light transmissive elements using flexural rigidity. A flexion arm enables coupling with cameras and other devices in areas non-proximate to a lens. A frame conjoined with the flexion arm enables attachment of the camera filter to a camera lens or lens housing.

A projector includes a projection lens, a distance information acquiring section that acquires distance information relating to the distance from the projector to a projection surface, a first imaging section that captures an image of the projection surface, a second imaging section that has an angle of view wider than the angle of view of the first imaging section and captures an image of the projection surface, and a control unit. The second imaging section is disposed in a position closer to the optical axis of the projection lens than the first imaging section. The control section causes the first imaging section to capture an image in a case where the distance from the projector to the projection surface is greater than or equal to a predetermined threshold and the second imaging section to capture an image in a case where the distance is smaller than the threshold.

A focusing state measuring apparatus for measuring a focusing state of a working apparatus with respect to a target object so as to perform work includes: a base plate installed in the working apparatus performing work on the target object and spaced apart from the target object; a first line beam generation unit provided on one side of the base plate and configured to irradiate a first line beam toward the target object; and a second line beam generation unit provided on one side of the base plate so as to be spaced apart from the first line beam generation unit in a first direction and configured to irradiate a second line beam toward the target object. The focusing state of the working apparatus with respect to the target object is determined according to states of the first line beam and the second line beam.

A distance detection device is provided, including a calculating unit that calculates a distance to a detection target using a length of time until floodlighted light is received by a light-receiving unit; a first detecting unit that detects whether detection target changing operation is being performed; a second detecting unit that detects variation in the distance calculated by the calculating unit; a shake correcting optical system that is driven based on a shake detection result and through which the floodlighted light passes; and a control unit that controls driving of the shake correcting optical system using an output from the first detecting unit and an output from the second detecting unit.

A method of automatically focusing a projector in a projection system is provided that includes projecting, by the projector, a binary pattern on a projection surface, capturing an image of the projected binary pattern by a camera synchronized with the projector, computing a depth map from the captured image, and adjusting focus of the projector based on the computed depth map.

A method of automatically focusing a projector in a projection system is provided that includes projecting, by the projector, a binary pattern on a projection surface, capturing an image of the projected binary pattern by a camera synchronized with the projector, computing a depth map from the captured image, and adjusting focus of the projector based on the computed depth map.

A range finder capable of adjusting light flux includes a light-emitting element configured to emit a light beam, a lens element, a light-shielding element configured to adjust light flux, and an image sensor. The light beam emitted by the light-emitting element is reflected by an object, passes through the lens element, and is projected to the image sensor. The light-shielding element is disposed between the object and the image sensor, and on a path of the light beam.