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Spatial-heterodyne interferometry for transmission (shift) measurementsSpatial-heterodyne interferometry for transmission (shift) measurements description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060192972, Spatial-heterodyne interferometry for transmission (shift) measurements. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of, and claims a benefit of priority under 35 U.S.C. 120 from copending utility patent application U.S. Ser. No. 10/649,251, filed Jun. 23, 2003, the entire contents of which are hereby expressly incorporated herein by reference for all purposes. BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] The invention relates generally to the field of spatial-heterodyne interferometry (SHI). More particularly, the invention relates to methods and machinery for obtaining spatial-heterodyne interferometry for transmission (SHIFT) and spatial-heterodyne interferometry for reflection and transmission (SHIRT) measurements. [0005] 2. Discussion of the Related Art [0006] U.S. Pat. Nos. 6,078,392 and 6,525,821 relate to Direct-to-Digital Holography (DDH). In DDH, a reflected object wavefront is combined with a reference wavefront at a small angle on the surface of a digital imaging device. The small angle generates a set of linear fringes that spatially heterodynes the reflected object wavefront. Fourier analysis is then used to isolate the image at the heterodyne frequency and reconstruct the complex wavefront, Voelkl (1999). [0007] DDH is an implementation of spatial-heterodyne interferometry with Fourier reconstruction to capture complex wavefronts reflected from the surface of an object. When a wavefront strikes the surface of an object, the shape of the surface is imbedded in the phase of the wavefront and the reflectivities of the surface are contained in the intensity of the reflected wave. This reflected wave is combined with a reference wave at the digital imaging device so that they interfere and create a set of linear interference fringes. These linear interference fringes then contain the phase and amplitude information of the object wave. In Fourier space, this object wave information shows up centered around the spatial-frequency of the fringes. The recording of a wave's phase and amplitude information at a nonzero frequency is known as "heterodyning." [0008] However, DDH does not provide information regarding the interior of an object of interest and only provides information regarding the surface of the object. [0009] Meanwhile, phase contrast microscopy (PCM) is a well known technique that is commonly used to image biological specimens. PCM is particularly useful when a biological sample includes phase differentiable features that are of similar transmissibility. However, a limitation of PCM is that no complex wavefront information is provided, the phase information from PCM being represented by amplitude only. [0010] Recently, Jacob (2002) reported a technique in which transmission phase shift interferometry is used to measure phase differences between two points on a photolithographic mask. While this technique is able to measure phase changes, 30 seconds are required for each height measurement and, therefore, a slow scan would be required to measure phase changes across an interior portion of an object and a very long scan would be required to measure phase changes over an entire mask. Therefore, what is needed is an approach that can quickly provide complex wavefront information regarding an interior portion of an object. [0011] Heretofore, the requirements of both providing complex wavefront information regarding an interior portion of an object and providing that information quickly have not been met. What is needed is a solution that simultaneously solves both of these problems. SUMMARY OF THE INVENTION [0012] There is a need for the following aspects of the invention. Of course, the invention is not limited to these aspects. [0013] According to an aspect of the invention, a process comprises: digitally recording a spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis using a reference beam and an object beam; Fourier analyzing the digitally recorded spatially-heterodyned hologram, by shifting an original origin of the digitally recorded spatially-heterodyned hologram to sit on top of a spatial-heterodyne carrier frequency defined by an angle between the reference beam and the object beam, to define an analyzed image; digitally filtering the analyzed image to cut off signals around the original origin to define a result; and performing an inverse Fourier transform on the result, wherein the object beam is transmitted through an object that is at least partially translucent. According to another aspect of the invention, a machine comprises: a source of coherent light energy; a reference beam subassembly optically coupled to the source of coherent light; an object beam subassembly optically coupled to the source of coherent light; a beamsplitter optically coupled to both the reference beam subassembly and the object beam subassembly; and a pixilated detection device optically coupled to the beamsplitter, wherein the object beam subassembly includes an object that is at least partially translucent, the object transmissively optically coupled between the source of coherent light energy and the beamsplitter. [0014] According to another aspect of the invention, a process comprises: digitally recording a first spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis using a first reference beam and a first object beam; digitally recording a second spatially-heterodyned hologram including spatial heterodyne fringes for Fourier analysis using a second reference beam and a second object beam; Fourier analyzing the digitally recorded first spatially-heterodyned hologram, by shifting a first original origin of the digitally recorded first spatially-heterodyned hologram to sit on top of a first spatial-heterodyne carrier frequency defined by a first angle between the first reference beam and the first object beam, to define a first analyzed image; Fourier analyzing the digitally recorded second spatially-heterodyned hologram, by shifting a second original origin of the digitally recorded second spatially-heterodyned hologram to sit on top of a second spatial-heterodyne carrier frequency defined by a second angle between the second reference beam and the second object beam, to define a second analyzed image; digitally filtering the first analyzed image to cut off signals around the first original origin to define a first result; and digitally filtering the second analyzed image to cut off signals around the second original origin to define a second result; performing a first inverse Fourier transform on the first result, and performing a second inverse Fourier transform on the second result, wherein the first object beam is transmitted through an object that is at least partially translucent and the second object beam is reflected from the object. According to another aspect of the invention, a machine comprises: a source of coherent light energy; a transmission reference beam subassembly optically coupled to the source of coherent light; a reflection reference beam subassembly optically coupled to the source of coherent light; an object beam subassembly optically coupled to the source of coherent light, the object beam subassembly including a transmission object beam path and a reflection object beam path; a transmission beamsplitter optically coupled to both the transmission reference beam subassembly and the object beam subassembly; a reflection beamsplitter optically coupled to both the reflection reference beam subassembly and the object beam subassembly; and a pixilated detection device optically coupled to at least one member selected from the group consisting of the transmission beamsplitter and the reflection beamsplitter, wherein the object beam subassembly includes an object that is at least partially translucent, the object i) transmissively optically coupled between the source of coherent light energy and the transmission beamsplitter and ii) reflectively optically coupled between the source of coherent light energy and the reflection beamsplitter. [0015] These, and other, aspects of the invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating various embodiments of the invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many substitutions, modifications, additions and/or rearrangements may be made within the scope of the invention without departing from the spirit thereof, and the invention includes all such substitutions, modifications, additions and/or rearrangements. BRIEF DESCRIPTION OF THE DRAWINGS [0016] The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore nonlimiting, embodiments illustrated in the drawings, wherein identical reference numerals (if they occur in more than one view) designate the same elements. The invention may be better understood by reference to one or more of these drawings in combination with the description presented herein. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale. [0017] FIGS. 1A-1B illustrate an example of an intensity hologram formed on a CCD (charge coupled device) sensor from a chrome-on-glass target where FIG. 1B is an enlarged region showing the linear sinusoidal fringe pattern modulated by the surface topology and material characteristics, representing an embodiment of the invention. [0018] FIGS. 2A-2B illustrate (FIG. 2A) the magnitude of the full frequency spectrum of a hologram and (FIG. 2B) the centered and low-pass filtered side-band of the hologram, representing an embodiment of the invention. [0019] FIGS. 3A and 3B illustrate (FIG. 3A) the resultant amplitude of a portion of the chrome-on-glass target and (FIG. 3B) the phase reconstruction of the portion of the chrome-on-glass target, representing an embodiment of the invention. [0020] FIGS. 4A-4C illustrate schematic views of three transmission examples showing (FIG. 4A) the calculation of thickness given indices of refraction (FIG. 4B) the phase between different materials of same thickness and (FIG. 4C) the ability to calculate index of refraction for a material of known thickness, representing embodiments of the invention. [0021] FIGS. 5A-5D illustrate schematic views of the transformation of illumination wave to transmitted wave effected by four different objects, representing embodiments of the invention. Continue reading about Spatial-heterodyne interferometry for transmission (shift) measurements... Full patent description for Spatial-heterodyne interferometry for transmission (shift) measurements Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Spatial-heterodyne interferometry for transmission (shift) measurements patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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