236results about How to "Long focal length" patented technology

A wide-angle camera is fixed to direct an optical axis in a fixed direction. A telephotographic camera can be inclined in panning and tilting directions to change an aiming direction of its optical axis. An image signal from the wide-angle camera is evaluated. When an image of a moving object is identified in a frame captured by the wide-angle camera, directivity information corresponding to a position of the moving object is calculated based on a relative position to the center of the frame. In accordance with the directivity information, posture of the telephotographic camera is controlled to aim its optical axis at the moving object. Thereafter, the posture of the telephotographic camera is controlled continuously to place the image of the moving object in the center of the frame captured by the telephotographic camera. The telephotographic camera captures the moving object while tracking it.

A single, hard-mounted set of optics is utilized to replace a two field-of-view system for directed countermeasures. It includes within one continuous but distorted field of view the capability to detect, acquire and characterize targets at the edge of the field while precisely tracking with high target fidelity at the field center. With multiple targets, both tracking of a primary target and acquisition of a secondary target can occur simultaneously, greatly improving countermeasure effectiveness.

An improved particle effect projector is disclosed that reduces the energy density of a laser beam projected through a movie theater or other entertainment venue, comprising an F-theta lens, a beam expander and a beam focuser with a long focal length that approximates the distance between the particle effect projector and the movie screen or other surface onto which the particle effect beam is being projected.

A high performance zoom lens system suitable for use with a camera is disclosed. The zoom lens systems employs liquid optics and a movable lens group to provide optical performance over the zoom focal length range at focus distances from close to infinity. The system also provides compensation for undesirable thermally induced effects by adjustments of the zoom group and the variably shaped optical surface in the liquid lens cell.

A compact and substantially achromatic optical lens system (100, 200) comprising an electrowetting lens (104, 204) is provided. The optical lens system is using an electrowetting lens in which at least one of the entrance window surface (117, 217) or exit window surfaces (219), being in contact with one of the fluids (112, 212, 113, 213), has a curvature. When the sign of the curvature of that surface has the same sign as the curvature of the meniscus when no voltage is applied, a low building height is achieved. The optical element (104, 204) not only acts as a focussing or zooming device, but that it also acts as an aberration reduction element for the other elements in the optical lens system (100, 200).

An imaging apparatus and an image sensor including the same are provided. The imaging apparatus includes first, second, and third optical devices. At least one of the first, second, and third optical devices is a thin-lens including nanostructures.

An electronic camera is provided with a power-saving S-AF mode and a C-AF mode as focus adjustment modes. In the S-AF mode, focus adjustment is performed upon half depression of a release button. In the C-AF mode, the focus adjustment is repeated during a shooting mode regardless of the half depression of the release button to simplify the focus adjustment of a shooting time so that shooting is smoothly performed. When the electronic camera is set to the shooting mode, an AF controller obtains an Ev value representing subject brightness. The Ev value is compared with a threshold value stored in a memory. When the Ev value exceeds the threshold value, the focus adjustment mode is changed to the S-AF mode. When the Ev value falls below the threshold value, the focus adjustment mode is changed to the C-AF mode.

An image display apparatus which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and fight in weight and hence unlikely to cause the observer to be fatigued. The image display apparatus includes an image display device and an ocular optical system for projecting an image formed by the image display device and for leading the projected image to an observer's eyeball. The ocular optical system (3) has three surfaces, and a space formed by the three surfaces is filled with a medium having a refractive index larger than 1. The three surfaces include, in the order in which light rays pass in backward ray tracing from the observer's eyeball (1) to the image display device (4), a first surface (5) which functions as both a refracting surface and an internally reflecting surface, a second surface (6) which is a reflecting surface facing the first surface (5) and decentered or tilted with respect to an observer's visual axis (2), and a third surface (7) which is a refracting surface closest to the image display device (4), so that reflection takes place three times in the path from the observer's eyeball (1) to the image display device (4).

There is provided a see-through display device. A see-through display device comprises a liquid crystal plate filled with liquid crystals; first and second orientation plates respectively positioned on upper and lower surfaces of the liquid crystal plate, and controlling an initial alignment state of the liquid crystals; first and second conductive plates respectively positioned on an upper surface of the first orientation plate and a lower surface of the second orientation plate, and being filled with a conductive material; first and second transparent plates respectively positioned on an upper surface of the first conductive plate and a lower surface of the second conductive plate; first and second polarizing plates respectively positioned on an upper surface of the first transparent plate and a lower surface of the second transparent plate; and a transparent light guide plate spaced apart from a lower surface of the second polarizing plate, and allowing beams incident from a light source positioned at one side thereof to be totally reflected and emitted upward. Accordingly, a see-through display device comprises a transparent optical display device and a transparent light guide plate having a light source disposed at one side thereof, so that the display device can be optically transparent even when it is not operated.

A system for capturing aerial images, the system comprising at least one overview camera, a plurality of detail cameras, and a frame for holding the cameras, each detail camera having a longer focal length than the at least one overview camera, each detail camera mounted at a different angle laterally so that the fields of view of the detail cameras overlap to form an extended lateral field of view, the frame attachable to the floor of an aircraft above a camera hole, thereby providing the cameras with a view of the ground below the aircraft through the camera hole.

The invention, which belongs to the field of reconnaissance systems, particularly relates to a coaxial photoelectric reconnaissance system comprising a Cassegrain non-focus coaxial two-inverse commonoptical path, an infrared imaging system and a visible light imaging system. The Cassegrain non-focus coaxial two-inverse common optical path includes a primary mirror and a secondary mirror; and light emitted by a target is reflected and collimated by the primary mirror and the secondary mirror twice and then parallel light is emitted. A reflection mirror is arranged at the path of parallel lightemission by the Cassegrain non-focus coaxial two-inverse common optical path to realize light turning of parallel light. A first transmission-reflection mirror is arranged at the reflection light path of the reflection mirror to realize reflection of infrared light and transmission of visible light. The visible light imaging system is used for receiving visible light transmitted by the first transmission-reflection mirror and carrying out imaging; and the infrared imaging system is used for receiving infrared light reflected by the first transmission-reflection mirror and carrying out imaging. Therefore, visible-light and infrared-band optical systems and a laser optical system are integrated under the condition of small size, so that target observation in various environments is realized.

The invention relates to a method for authenticating a diffractive element, e.g., a hologram, on an object or document (2), wherein at least two images of the diffractive element are recorded by means of a portable device (1). The recordings are taken in different spatial orientations of the portable device in relation to the diffractive element. Recording data are created from the images and the associated spatial orientations. The recording data are electronically compared with reference data. The comparison can be performed locally or in a server-based manner.

A large-relative-aperture long-focal length non-cooled infrared athermalization optical system is arranged in front of the focal plane in the light spreading direction, and is composed of a main reflector, a secondary reflector, a first positive crescent lens, a second positive crescent lens, a reflection/diffraction mixed lens, a movable lens and a second negative crescent lens which are coaxially arranged in parallel. The system adopts a cassette system to increase the optical path by multiple reflections of light, thereby realizing the long coking of the optical system, wherein F<#> is 1; the focal length is 500mm; the center block is smaller or equal to 0.3; and the optical total length and focal length ratio is smaller than or equal to 0.64. Through the secondary imaging, the impact of stray light on the image quality of the system can be effectively inhibited. With the utilization of characteristics of negative dispersion and negative thermal expansion coefficient of the diffractive element and the reasonable distribution of the focal power of the reflection/diffraction mixed lens, the defocusing amount caused by the infrared optical system due to the temperature change is reduced, and combined with the mechanical active athermalization, the image plane defocusing compensation of the system in the temperature range of from -40 DEG C to +60 DEG C is achieved.

In a projector lens system including at least three lens elements and telecentric on a side of an optical modulator, two of the lens elements located on outer most ends of the projector lens system facing conjugate points of the projector lens system consist of plastic lenses, and an aperture stop of the projector lens system is located between the two outer most lens elements while at least one of the lens elements other than the two outer most lens elements most adjacent to the aperture stop consists of a glass lens. Thereby, the cost and weight of the projector lens system can be reduced while achieving the required optical properties.

The invention relates to an off-axis reflective imaging optical system. The apexes of a first main reflector, a second auxiliary reflector and a third reflector are all on an optical axis of the system and used in an off-axis mode; the first main reflector and the third reflector are of spherical surfaces, and the second auxiliary reflector and a fourth reflector are of aspheric surfaces; the first main reflector converges the incident light beam reflected by the entrance pupil onto the surface of the first main reflector to reduce the diameter of the incident light beam; the second auxiliary reflector refracts the light beam converged by the first main reflector and corrects some spherical and comatic aberration generated by the first main reflector; the third reflector further refracts the light beam converged by the second auxiliary reflector and corrects some astigmatism and curvature of the field, which are led by a second main reflector; the fourth reflector refracts the light beam converged by the third reflector, leads aberration for balancing the aberration of the system, and enables the light beam to be imaged on the image plane. The off-axis reflective imaging optical system has the advantages of being long in focal length, large in image plane, less in the number of aspheric surfaces and good in imaging quality. And optical elements of the system are low in producing difficulty.

The present invention discloses a three-dimensional coordinate measurement method based on line structure light scanning. The method comprises the steps of (S1) a line laser emits laser, and a laser line is formed on a measured object, (S2) the image information corresponding to the laser line formed on the measured object, (S3) a control processing system calculates a corresponding three-dimensional coordinate according to the image information of the (S2) and controls the object to move for a particular distance, (S4) the steps (S2) and (S3) are repeated, and the complete three-dimensional coordinate of the measured object is obtained. By using the method of the invention, the laser line formed on the measured object by the line laser is reflected for many times through an optical system, the image information of the laser line can be obtained from different positions with one camera, the block problem in a single-camera visual sensor is solved, the effect of a double-camera visual sensor is achieved, the cost is low, and a control processing system is simple.

The invention discloses a design method for a pure medium electromagnetic lens based on a meta-surface. The method includes the following steps that firstly, according to medium materials of the lens and the wavelength of working electromagnetic waves, the relation between phase changes and medium thicknesses is obtained; secondly, according to requirements for the type and focal length of the lens (a convex lens or a concave lens or a reflecting mirror), needed distribution of phase jumps is worked out; thirdly, according to phase distribution requirements, the medium lens with the corresponding thickness is established in electromagnetic simulation software, is simulated and finely adjusted and then can be manufactured, wherein the phase distribution phi is obtained according to the requirement of the lens designed in the second step, distribution of the medium thicknesses is worked out, and modeling and simulating are conducted in the electromagnetic simulation software. The design method is simple and flexible; along with reduction of incidence wavelengths, the focal length of the lens will be increased; a lens set composed of the lens and a traditional lens can eliminate chromatic aberration.

The invention discloses an optical lens. The optical lens sequentially comprises, from the object side to the image side, a first lens which has positive focal power and of which the convex side faces the object side, a second lens of which the convex side faces the object side, a biconcave third lens, a fourth lens which has positive focal power, a fifth lens, and a sixth lens. The optical lens provided by the invention has the advantages of high resolution, small distortion, large aperture and small size. Moreover, the focal length is relatively large, the field range is reduced, the details of the object can be observed better under the condition of same image plane size, and the demand for small-field observation is satisfied.

A compact and light-weighted projection lens system that is capable of projecting an image at an angle as wide as 75 degrees with sufficient field angle and brightness as represented by F number of approximately 2.4, that is capable of effectively correcting chroic aberration of magnification and aberration of distortion and exhibiting optical stability against environmental variations, and that is suitable for obtaining an extraordinarily fine image by the magnification and projection. In the projection lens system that comprises first to third groups of lenses in the order from the closest a magnified image where the first lens group of negative refractive power includes one or more aspherical lenses each having an aspherical plane on one or both of the surfaces, the second lens group of positive refractive power includes one or more positive lenses, and third lens group of positive refractive power includes one or more cemented triplet lenses comprised of three lenses of positive, negative, and positive attributes joined in this order, a projection lens system is characterized by terms and conditions defined as in the following formulae:

0.9<|f1|/f<1.4  (1)

2.1<f2/f<3.4  (2)

1.9<f3/f<2.8  (3)

where f is a total focal length throughout the projecting lens system, f1 is a focal length of the first group of lenses, f2 is a focal length of the second group of lenses, and f3 is a focal length of the third group of lenses.

The invention discloses a visual sensor of linear structure light scanning measurement equipment. The visual sensor concretely comprises a linear laser device, a camera, a left reflecting mirror, a right reflecting mirror, a semitransparent and semi-reflecting mirror and a rear reflecting mirror. Laser rays of the laser device formed on a measured object are reflected by the left reflecting mirror and the semitransparent and semi-reflecting mirror in turn, and finally form a first image about the laser rays on the camera. The laser rays on the measured object are also reflected by the right reflecting mirror and the rear reflecting mirror and then transmit through the semitransparent and semi-reflecting mirror and form a second image about the laser rays on the camera. Three-dimensional coordinates can be completed if the camera can acquire one of the images about the laser lays. The blocking problem of a single-camera visual sensor can be solved so that the effect of a double-camera visual sensor can be achieved, cost is lower and a control processing system is simpler.

An optical system is provided and includes a light-sensing element, at least one optical lens, a reflecting unit and a first driving assembly. The reflecting unit includes a reflecting surface, configured to receive an incident light and to reflect a reflecting light. The reflecting light travels through the optical lens into the light-sensing element. The first driving assembly is configured to control the reflecting unit to move along a first axis direction, so as to adjust a focus position of the reflecting light on the light-sensing element.