49 results about "Catadioptric system" patented technology

A catadioptric system includes: a first image forming optical system that includes at least two reflecting mirrors and forms a first intermediate image of a first plane with light originating from the first plane; a second image forming optical system that includes at least two reflecting mirrors and forms a second intermediate image of the first plane with light having traveled via the first image forming optical system; and a refractive type of third image forming optical system that forms a final image of the first plane onto a second plane with light having traveled via the second image forming optical system, and optical members constituting the first image forming optical system, the second image forming optical system and the third image forming optical system are all disposed along a single linear optical axis.

Certain embodiments described herein comprise a telescope comprising primary and secondary mirrors and a corrector. The primary mirror has a first curved reflecting surface having a non-hyperbolic shape. The second secondary mirror has a second curved reflecting surface having a hyperbolic shape. The corrector comprises substantially optically transmissive material. The primary mirror, the secondary mirror, and the corrector are disposed along an optical path such that light propagates through the corrector to the primary mirror and from the primary mirror to the secondary mirror. In certain embodiments, the shapes of the first and second curved reflecting surfaces of the primary and second mirrors, respectively, and the shape and the index of refraction of the optically transmissive material of the corrector are such that the telescope is aplanatic.

A system for multiple mode imaging is disclosed. The catadioptric system has an NA greater than 0.65, and preferably greater than 0.9, highly corrected for low and high order monochromatic aberrations. The system employs unique illumination entrances and optics to collect reflected, diffracted, and scattered light over a range of angles. Multiple imaging modes are possible by varying the illumination geometry and apertures at the pupil plane. Illumination can enter the catadioptric optical sytems using an auxiliary beamsplitter or mirror, or through the catadioptric elements at any angle from 0 to 85 degrees from vertical. The system may employ a relayed pupil plane, used to select different imaging modes, provide simultaneous operation of different imaging modes, Fourier filtering, and other pupil shaping operations.

A catadioptric system includes a first catadioptric group, a second catadioptric group, and a lens group disposed in axial alignment with each other. The first catadioptric group includes a solid lens having an input surface, a primary reflective surface, secondary reflective surface and an exit surface. The primary reflective surface is a curved surface concave towards the secondary reflective surface. A light flux entering through the input surface undergoes more than two reflections between the primary and secondary reflective surfaces, prior to exiting through the exit surface. At least one of the primary reflective surface and secondary reflective surface has a continuous and smooth topological profile.

A catadioptric telescope is a modified version of a conventional Maksutov-Cassegrain optical telescope. In accordance with the invention, the reflecting surfaces of the primary mirror and the secondary spot mirror are on the second surfaces of the primary mirror and correcting lens, respectively. In further accordance with the invention, two of these telescopes can be joined together to form a binocular telescope array. The array can be easily customized to suit different remote sensing/satellite applications.

This invention describes an apparatus and method for generating artificial stars for the simple collimation of catoptric, dioptric, and catadioptric telescopes using a light source along with an appropriate hologram and housing to generate collimated laser beams that enter the front aperture of the telescope. The apparatus of this invention can be fastened to the outside of the telescope aperture. In addition, this invention allows the apparatus position to be adjusted at its tip and tilt axis to center an artificial star under the view of the ocular. The light source illuminates the hologram from some off axis position. Once the hologram is illuminated, the collimated beam emanates from the hologram with a slightly different angle. When these beams are then viewed with the telescope they appear as artificial stars.

The catadioptric system includes a first optical imaging system (catadioptric part) causing a light flux from an object to form an intermediate image and a second optical imaging system (dioptric part) causing the light flux from the intermediate image to form an image. In the first optical imaging system, the light flux sequentially passes a first transmissive portion, a second reflective portion, a first reflective portion and a second transmissive portion. In the second optical imaging system, consecutive four lens surfaces among plural lens surfaces placed between an aperture stop and an image surface have a negative combined refractive power, and a condition of −0.52<φ_{4n<sub2>—</sub2>max}·Y_max<−0.14 is satisfied, φ_{4n<sub2>—</sub2>max} represents a maximum value of the negative combined refractive power, and Y_max represents a maximum object height in a field-of-view of the catadioptric system at the object.

The catadioptric system includes a first imaging optical system collecting light from an object and a second imaging optical system causing the light from the first imaging optical system to form an intermediate image and to cause the light from the intermediate image to form an optical image. The first imaging optical system includes a first optical element including a first light transmissive portion and a first back reflective portion, and a second optical element including a second light transmissive portion and a second back reflective portion. The first light transmissive portion, the second back reflective portion, the first back reflective portion and the second light transmissive portion introduce the light from the object to the second imaging optical system. The second imaging optical system includes an aspheric lens having a negative refractive power on and around the optical axis and a positive refractive index in its peripheral portion.

A catadioptric system includes: a catadioptric unit configured to form an intermediate image of an object; a refracting portion configured to form an image of the intermediate image; a first field lens configured to guide optical flux from the catadioptric unit to the refracting portion; and a second field lens configured to guide the optical flux from the refracting portion toward an image side. The first and the second field lenses each include a positive lens and a negative lens adjacent to each other, and wherein where νIFLp1 and νIFLn1 are respectively Abbe numbers of materials of the positive lens and the negative lens of the first field lens, and νFLp1 and νFLn1 are respectively Abbe numbers of materials of the positive lens and the negative lens of the second field lens, conditions

20<νIFLp1−νIFLn1 and

20<νFLp1−νFLn1

are satisfied.

The invention relates to a method for homography estimation by using a public autopolar triangle of a spherical image, which comprises the following steps of: taking a sphere in space as a target, shooting two images of the sphere in the space from different positions under a parabolic catadioptric system, and fitting a mirror surface contour projection equation, a target projection equation and an antipodal sphere image equation; Secondly, respectively calculating a characteristic value and a characteristic vector of a matrix formed by the spherical image and the antipodal spherical image inthe two images; then, by matching characteristic values, three pairs of line correspondence are obtained, and the three pairs of line correspondence are three pairs of corresponding edges of the public self-polar triangle; then, connecting the intersection points of the public self-polar triangle and the quadratic curve to obtain a fourth pair of line correspondence which is correspondingly positioned in the public self-polar triangle; and finally, the four pairs of lines are correspondingly subjected to SVD decomposition to obtain a homography matrix.

Embodiment of invention discloses a system and a method for determining a three-dimensional (3D) location of a folding point of a ray between a point in a scene (PS) and a center of projection (COP) of a camera of a catadioptric system. One embodiment maps the catadioptric system, including 3D locations of the PS and the COP on a two-dimensional (2D) plane defined by an axis of symmetry of a folding optical element and the PS to produce a conic and 2D locations of the PS and COP on the 2D plane, and determines a 2D location of the folding point on the 2D plane based on the conic, the 2D locations of the PS and the COP. Next, the embodiment determines the 3D location of the folding point from the 2D location of the folding point on the 2D plane.

The present invention is a catadioptric system having a reticle optical group, a beam splitter, an aspheric mirror, a baffle plate, a folding mirror and a semiconductor wafer optical group. The reticle optical group, the beam splitter and the semiconductor wafer optical group are placed on the same beam axis, different from aspheric mirror and folding mirror axis. The light passes through an image pattern on the reticle and is reflected by the beam splitter onto the aspheric mirror. The aspheric mirror reflects the light back through the beam splitter onto the folding mirror. The folding mirror reflects the light back to the beam splitter. The beam splitter reflects the light onto the semiconductor wafer optical group. A plurality of quarter wave plates can be placed in optical paths between optical elements of the present invention to change polarization of an incoming light. Before light passes through the semiconductor wafer optical group, it passes through the baffle plate, which prevents any background scattered light caused by internal reflections within the beam splitter from entering the semiconductor wafer optical group. In another embodiment, a spacer plate is inserted into the beam splitter. The spacer plate creates an offset between reticle optical group beam axis and semiconductor wafer optical group beam axis. This reduces direct passage of light from reticle optical group to semiconductor wafer optical group.

The invention proposed the catadioptric system, which consists of two main components: the first component comprising the two reflective mirrors, in which surface distortion of mirror 1 is parabolic, surface distortion of mirror 2 is aspheric; the second component is a relay consisting of three lenses: lens 1, lens 2, and lens 3 arranged after the medial image plane correspondingly; it plays an important role in fixing the pupil's position to match the position of the cold shield of the sensor and eliminating absolutely the aberration to ensure receiving good quality image at the sensor plane.

A device for taking long-distance images includes, successively: a catadioptric optical system and an optical system to shape the beam positioned close to the first image generated by the catadioptric system, which adjusts the exit aperture of the catadioptric system on a second image of the aperture in an image space of a variable focal length optical system. The catadioptric optical system and the optical system to shape the beam generates a third image of the observed scene. A focal plane is superposed over an image plane of the catadioptric optical system and the optical system to shape the beam. A projection lens receives the light beam output by the variable focal length system and forms a fourth image of the observed scene at the focal plane of the projection lens. An image sensor is positioned at the focal plane of the projection lens.

A catadioptric unit includes, in order from an object side to an image side, a first optical element including a first transmissive unit having positive refractive power disposed in the vicinity of an optical axis and, on the object side thereof, a first reflective unit disposed at an outer circumference relative to the first transmissive unit and having a reflective surface; and a second optical element including a second transmissive unit having negative refractive power in the vicinity of the optical axis and, on the image side thereof, a second reflective unit disposed at an outer circumference relative to the second transmissive unit and having a reflective surface. Radii of curvature of object-side and image-side surfaces of the second optical element, a thickness along the optical axis and a refractive index of a material of the second optical element are set to satisfy predetermined conditions.

The invention provides a measurement method of a plane mirror included angle in a multiplane-mirror catadioptric system. Technical schemes of the invention comprise the following steps: by using the multiplane mirrors and a monocular camera, establishing a data acquisition system, calibrating a shooting angle and a diaphragm of a real camera and collecting data of an object in a shooting area; acquiring marking points through adopting a threshold method; acquiring center positions of the marking points by using an area gap filling method; elliptically fitting the obtained marking points; calculating the position of circle points by using an ellipse; calculating pole positions by using a limit-restraint technology; finally acquiring the plane mirror included angle by using the poles and the circle points. In the traditional multiplane-mirror catadioptric system, the plane mirror included angle is difficult to be measured because of utilization of a plurality of plane mirrors. By using the method of the invention, the above problem can be solved, calibration precision of the monocular camera can be raised so that accuracy of three-dimensional scene reconstruction and stability of system can be improved.