The Aerospace Corporation

David Wheeler Warren

John A Hackwell

Nielson Wade Schulenburg

David J Gutierrez

Michael Arthur Rocha

James H Hecht

Donald J Rudy

Michael G Martino

Mark Alan Chatelain

Disclosed herein are spectral imaging systems having an internally folded prism, which can have four different refracting surfaces. A first angle defines the spatial relationship between the first and second refracting surfaces. The first angle can have a range between 45-95 degrees. In some embodiments, the first angle can be 70 degrees. The spatial relationship of the third and fourth refracting surfaces can be defined by a second angle, which can be the same as the first angle. Finally, the spatial relationship of the second and third refracting surfaces can be defined by a third angle, which can have a range between 90-145 degrees. The prism index of refraction, the first, second, and third angles are selected such that TIR is achieved at two of the refracting surfaces. Additionally, these prism parameters are selected such that a 180 degrees fold of the optical path is achieved entirely within the prism.

Compact light dispersion system

An image acquisition system with motion compensation is disclosed. Embodiments of the system include: includes a rectilinear lens assembly, a first 2D-image sensor, and a motion compensation module. The rectilinear lens assembly has an optical axis, an object plane, and a focal plane. During an image acquisition cycle, the rectilinear lens assembly is positioned such that the optical axis is orthogonal to the object plane while the first 2D-image sensor is parallel to the object plane. The motion compensation module can determine a motion vector of an image scene in the object plane. In response the determined motion vector, the rectilinear lens assembly and the first 2D-image sensor relative are translated relative to each other in two dimensions to compensate for the motion of the image scene.

Methods and systems for motion compensation and stereoscopic images generation

Aspects of the disclosure relate to correction of aberration in optical systems. In one aspect, correction of aberration can rely on a corrector lens that is movably positioned between an objective lens and an optical member, and that can introduce a perturbation to a convergent beam of light that forms an image at the substantially the focal point of the objective lens. The formed image presents aberration and such a perturbation can correct at least a portion thereof. In another aspect, the corrector lens can embody or can comprise a positive power lens, that introduces the perturbation via, at least in part, a radially symmetric wavefront correction into the convergent beam, where such a correction varies as a fourth power of a radial distance from a central axis of propagation of the convergent beam of light.

Architectures and techniques for optical aberration correction

A method for measuring spectral characteristics includes capturing spectral-spatial data that includes radiance measurements over spectrally flat, highly emissive surface portions of a sample material and heater at least two different heater temperatures for transmissive and/or emissive configurations. Temperatures of the sample material and heater are determined at the different heater temperatures for each configuration using, in each instance, radiance measurements taken after the temperatures of the heater and sample material have both stabilized. The transmissivity of the sample material is determined using the temperatures determined in the transmissive configuration and spectral-spatial data collected at selected points of interest over the sample material. The emissivity of the sample material is determined using the temperatures determined in the emissive configuration, the spectral-spatial data collected at selected points of interest over the sample material, and the transmissivity. The reflectivity of the sample material is determined using the emissivity and transmissivity.

Nadir emissive hyperspectral measurement operation (NEHMO)

A spectrometer apparatus includes a refractor element, a slit, a detector, a diffraction grating, and a corrector lens. The refractor element includes a rear surface and a front surface. The slit provides an optical path to the rear surface of the refractor element, and is configured to transmit an image incident thereupon along the optical path. The detector is positioned facing the rear surface of the refractor element. The diffraction grating faces the front surface of the refractor element, and is configured to spectrally disperse and reimage the image of the slit toward the front surface of the refractor element. The corrector lens is positioned between the refractor element and the diffraction grating such that the image is provided to the detector corrected for a spherical aberration caused by a separation distance between the detector and the rear surface of the refractor element.

Compact, high-throughput spectrometer apparatus for hyperspectral remote sensing

An all reflective telescope system generally includes two spherical mirrors, one mild aspheric mirror and one aspheric mirror all centered about a common telescope axis and imaging on a focal surface for easy manufacture, very long focal length, wide field of view, high resolution, compact volume and low weight particularly well suited for space observations, and in a detailed form includes a sectional concave hyberboloidal primary mirror, a circular mild convex ellipsoidal secondary mirror, a sectional concave spherical tertiary mirror and a sectional convex spherical quaternary mirror for focusing an extended distant object onto a concave cylindrical focal surface having a linear array of charge coupled detectors for high resolution imagery, the telescope having high performance operation near diffraction limits and operating at detector resolution limits.

Wide field, long focal length, four mirror telescope

A device for the spectral dispersion of light suitable for use in a spectrographic mode with arrays of solid state photo-detectors. Light from an entrance aperture passes through a dispersing prism with two curved, refracting surfaces both operating near their aplanatic conjugates. After being reflected by a concave mirror located behind the prism, light returns through the prism in the opposite direction, the refractions at each face again being nearly aplanatic. Spectrally dispersed images of the entrance aperture are formed on a plane well separated from the entrance aperture and nearly normal to the incident light rays. Good image quality is maintained over a broad range of operating wavelengths simultaneously, allowing large spectral intervals to be surveyed without moving any of the elements of the system.

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Los Angeles, CA, United States of America

David Wheeler Warren