Digital interference holographic microscope and methods
AssigneeUniversity of South Florida
InventorMyung K. Kim
Life of this patent
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Abstract
A simple digital holographic apparatus and method allow reconstruction of three-dimensional objects with a very narrow depth of focus or high axial resolution. A number of holograms are optically generated using different wavelengths spaced at regular intervals. They are recorded, such as on a digital camera, and are reconstructed numerically. Multiwavelength interference of the holograms results in contour planes of very small thickness and wide separation. Objects at different distances from the hologram plane are imaged clearly and independently with complete suppression of the out-of-focus images. The technique is uniquely available only in digital holography and has applications in holographic microscopy.
Claims9
A method for imaging a three-dimensional object comprising the steps of:
- (a) illuminating an object with radiation at a wavelength to form a reflected image beam;
- (b) providing a reference beam comprising the wavelength;
- (c) recording an interference pattern between the reference beam and the image beam;
- repeating steps (a)–(c) at a succession of different wavelengths separated by a predetermined wavelength step;
- computing a holographic image from the interference pattern for each wavelength;
- adding the holographic images together to form an intensity distribution pattern;
- extracting out a series of two-dimensional cross-sectional images from the intensity distribution pattern;
- correcting microscopic image distortion in the cross-sectional images;
- and
- reassembling the cross-sectional images into a three-dimensional model of the object.
A method for imaging a three-dimensional object comprising the steps of:
- (a) illuminating an object with radiation at a wavelength to form a reflected image beam;
- (b) providing a reference beam comprising the wavelength;
- (c) recording an interference pattern between the reference beam and the image beam;
- (d) recording an image of the object only;
- and
- (e) recording an image of the reference beam only;
- repeating steps (a)–(e) at a succession of different wavelengths separated by a predetermined wavelength step;
- computing a holographic image from the interference pattern for each wavelength;
- subtracting a zero-order intensity from each computed holographic image, wherein the subtracting step comprises subtracting the object-only and reference-beam-only images from the interference pattern;
- and
- adding the holographic images together to form an intensity distribution pattern.
A method for imaging a three-dimensional object comprising the steps of:
- (a) illuminating an object with radiation at a wavelength to form a reflected image beam;
- (b) providing a reference beam comprising the wavelength;
- (c) recording an interference pattern between the reference beam and the image beam;
- repeating steps (a)–(c) at a succession of different wavelengths separated by a predetermined wavelength step;
- computing a holographic image from the interference pattern for each wavelength;
- and
- adding the holographic images together to form an intensity distribution pattern, wherein the object comprises two two-dimensional objects positioned different distances from a source of the radiation, and further comprising the step of extracting out two two-dimensional cross-sectional images from the intensity distribution pattern, each image representative of one of the objects.
Dependencies are inferred from the claim text.