Abstract:
A method (10) comprises: obtaining (11) prepared image data captured by an image sensor receiving light propagated across a sample volume, containing a fluid possibly comprising microscopic objects of foreign origin, while illuminating the sample volume by coherent light, the prepared image data comprising, for a microscopic object, a prepared hologram pattern with prepared spatially alternating intensity formed by interference fringes; providing (12) filtered image data, comprising automatically filtering the prepared image data by an edge enhancing filter, the filtered image data comprising, for a prepared hologram pattern, a filtered hologram pattern; and automatically detecting (13), on the basis of the filtered hologram pattern, the presence of the microscopic object associated with the filtered hologram pattern in the sample volume of the fluid.
Abstract:
Currently known holographic recording media and sensors have a number of disadvantages, for example, silver halide-based recording media is expensive to produce and unsuitable for use in certain sensor applications, and photopolymer- based recording media make it difficult to record multiple holographic images, thus, generally, rendering them unsuitable for use in sensors. Holographic recording media according to an embodiment of the present invention may comprise a polymer matrix and a chemical group that dimerizes by forming a cyclic bridge through photocycloaddition. These holographic recording media are cost-effective, allow recording of multiple holographic images, and enable production of sensors with controlled observable response to an external stimulus.
Abstract:
A sensor device comprising a holographic element comprises a grating or hologram recorded in a holographic recording medium wherein at least one physical and/or chemical and/or optical characteristic of the holographic element or the image produced by it varies as a result of variation in relative humidity or moisture content in the air surrounding the element. Also provided is an acrylamide-based photopolymer and an acrylamide-based reflection hologram.
Abstract:
A holographic sensor comprising a thin film polymer matrix that undergoes a change in response to a substance to be sensed, the matrix containing within its volume a set of two or more holographic recordings, each recording providing a holographic image when the sensor is illuminated, wherein the presence or appearance of each image is visible to the eye as a function of the response of the sensor to the substance to be sensed. The images provide the dynamic range of the sensor. Such a sensor can be used to provide a visible image that changes or appears to the eye in response to an analyte.
Abstract:
A method of making a hologram (10) includes recording a first hologram in a holographic recording medium (14) at a first deformation ratio; changing the first deformation ratio to a second deformation ratio that is different from the first deformation ratio; and recording a second hologram in the holographic recording medium (14) at the second deformation ratio to form a recorded holographic medium.
Abstract:
The nature of a volume hologram limits its use in security and sensing applications. Accordingly, a volume hologram (1) segregated into a first (2) and second (3) region recording a first and second image, respectively, and wherein the second region (3) is responsive to stimulus while the first region is protected physically from stimulus is provided. Also provided is a volume hologram with a functional cover disposed thereon to regulate how the volume hologram interacts with the stimulus when in the presence of stimulus. A volume hologram with a removable cover disposed thereon to permit a first recorded image to be viewed, to protect the volume hologram from physical damage, to prevent the volume hologram from interacting with the stimulus, and to be removed, thereby permitting the volume hologram to interact with the stimulus is provided as well. In these ways, the usability of volume holograms in security and sensing applications is increased.
Abstract:
A sensor for the detection of an analyte, comprises a medium and, disposed therein, a hologram, wherein an optical characteristic of the medium changes as a result of a variation of a physical property of the medium, wherein the medium comprises a first polymer interpenetrated by a second, different polymer, and wherein the hologram is recorded in the first polymer and said variation arises as a result of interaction between the second polymer and the analyte.
Abstract:
A method for the detection of an analyte in a fluid, comprising contacting the fluid with a holographic element comprising a medium and a hologram disposed throughout the volume of the medium, wherein an optical characteristic of the element changes as a result of a variation of a physical property occurring throughout the volume of the medium, wherein the variation arises as a result of interaction between the medium and the analyte, and wherein the reaction and the variation are reversible; and detecting any change of the optical characteristic.
Abstract:
A holographic security or identification device (10) comprises an object, or a flexible substrate (12) configured to be conformable to a desired, curved shape; and a plurality of structures (14) formed on or in the object to have a desired curved configuration, or formed in or associated with the substrate and arranged to adopt a desired curved configuration when the substrate is conformed to a desired shape, wherein the plurality of structures (14) are configured to receive light (20) of a selected at least one wavelength or range of wavelengths and to produce, using the received light, a desired holographic image (22) for security or identification purposes when in the desired configuration.
Abstract:
A sensor which comprises a support medium and a hologram disposed therein, wherein an optical characteristic of the medium varies as a result of a change of a property of the medium, and wherein the medium is heterogeneous such that the change of property is heterogeneous.