1147 results about "Contrast level" patented technology

The invention relates generally to medical devices and methods for ocular imaging and, more particularly, to devices and methods for increasing contrast in an eye in which an imaging contrast agent is introduced into an aqueous humor outflow channel. For example, in one embodiment, the outflow channel may be Schlemm's Canal, or in another embodiment, the outflow channel may be an episcleral vein. Also disclosed are methods for implanting a trabecular stent via an ab extemo procedure with assistance of enhanced magnetic resonance imaging to restore a part or all of the normal physiological function of directing aqueous outflow for maintaining a normal intraocular pressure in an eye.

This invention provides a vehicle-borne system and method for traffic sign recognition that provides greater accuracy and efficiency in the location and classification of various types of traffic signs by employing rotation and scale-invariant (RSI)-based geometric pattern-matching on candidate traffic signs acquired by a vehicle-mounted forward-looking camera and applying one or more discrimination processes to the recognized sign candidates from the pattern-matching process to increase or decrease the confidence of the recognition. These discrimination processes include discrimination based upon sign color versus model sign color arrangements, discrimination based upon the pose of the sign candidate versus vehicle location and / or changes in the pose between image frames, and / or discrimination of the sign candidate versus stored models of fascia characteristics. The sign candidates that pass with high confidence are classified based upon the associated model data and the drive / vehicle is informed of their presence. In an illustrative embodiment, a preprocess step converts a color image of the sign candidates into a grayscale image in which the contrast between sign colors is appropriate enhanced to assist the pattern-matching process.

A system and method are disclosed for reconstructing contrast-enhanced CT images that are substantially free of beam-hardening artifacts. An imaging system includes a radiation source configured to project radiation toward an object to be scanned and an energy discriminating detector assembly having a plurality of detector elements and configured to detect radiation emitted by the radiation source and attenuated by the object to be scanned. The imaging system also includes computer programmed to count a number of photons detected by each detector element and associate an energy value to each counted photon and determine a material composition of a CT view from the number of photons counted and the energy value associated with each counted photon. The computer is also programmed to apply a weighting to the CT view based on the material composition of the CT view and reconstruct an image with differential weighting based on the weighting of the CT view.

The present invention provides a system and method for recognizing a 3D object in a single camera image and for determining the 3D pose of the object with respect to the camera coordinate system. In one typical application, the 3D pose is used to make a robot pick up the object. A view-based approach is presented that does not show the drawbacks of previous methods because it is robust to image noise, object occlusions, clutter, and contrast changes. Furthermore, the 3D pose is determined with a high accuracy. Finally, the presented method allows the recognition of the 3D object as well as the determination of its 3D pose in a very short computation time, making it also suitable for real-time applications. These improvements are achieved by the methods disclosed herein.

A micromachined ultrasonic transducer array that focuses in the elevation direction. A curved lens is used to narrow the beam width in the elevation direction so that contrast resolution is improved and clinically relevant. Alternatively, a curved probe is formed by bending a micromachined substrate to have a predetermined curvature. The invention is further directed to methods of manufacturing such transducers.

A light valve such as an active matrix LCD between crossed polarizers, utilizing, for instance, individual transistors to control each "pixel area" of the LCD and storage elements to store video signal data for each pixel, with optically shielded "dead spaces" between pixels to eliminate electric field cross-talk and non-information-bearing light bleed-through, is illuminated with a bright independent light source which creates a video image projected via specialized projection optics onto an internal or external screen without distortions, regardless of the angle of projection onto the screen. Use of heat sinks, IR reflective coatings, heat absorbing optics, optional fluid and a thermistor controlled pixel transistor bias voltage injection servo circuit stabilizes image performance, maintaining accurate color and contrast levels as the LCD changes temperature. In one embodiment of the invention, use of a multi-color LCD with a stepped cavity, producing different thicknesses of LCD for the different wavelengths that pass through it, allows a linear correspondence between the wavelengths passing through the LCD to produce true black, high contrast and CRT-like color rendition. A dichroic mirror arrangement is used to overlap differently colored pixels in the projected image. Use of striped mirrors duplicate pixels, where necessary, eliminating spaces between pixels, creating a continuous image with no apparent stripes or dots. A special venetian-blind type of screen is also disclosed and methods for using the system to view three-dimensional video are also explained.

Backlight intensity is adjusted in a terminal. An adaptation apparatus transmits a visual signal after optimizing brightness or contrast of the visual signal based on the backlight intensity information which is related to the adjusted backlight intensity, so that the user can enjoy digital item with reduced power consumption of the terminal.

A method for automatic left ventricle segmentation of cine short-axis magnetic resonance (MR) images that does not require manually drawn initial contours, trained statistical shape models, or gray-level appearance models is provided. More specifically, the method employs a roundness metric to automatically locate the left ventricle. Epicardial contour segmentation is simplified by mapping the pixels from Cartesian to approximately polar coordinates. Furthermore, region growing is utilized by distributing seed points around the endocardial contour to find the LV myocardium and, thus, the epicardial contour. This is a robust technique for images where the epicardial edge has poor contrast. A fast Fourier transform (FFT) is utilized to smooth both the determined endocardial and epicardial contours. In addition to determining endocardial and epicardial contours, the method also determines the contours of papillary muscles and trabeculations.

An apparatus for determining the refraction of a patient's eye includes a wavefront measurement device that determines aberrations in a return beam from the patient's eye viewing a target through a corrective test lens in the apparatus. The wavefront measurement device preferably outputs an display representative of the quality of vision afforded the patient through the test lens. The display may be, e.g., a representation of a Snellen chart convolved with the optical characteristics of the patient's vision, an overall quality of vision scale, or the optical contrast function, all of which are based on the wavefront measurements of the patient's eye. The examiner may use the display information to conduct a refraction examination or other vision tests without the subjective response from the patient.

Pulsating light is used to penetrate a user's finger placed an input surface (which can be a fiber optic surface) of a video camera to avoid the effects of bloodflow from a normal human pulse on the quality of the image which would otherwise change the contrast of the image. The use of pulsating light of shorter durations than a typical human pulse provides an accurate image of a portion of a finger for identification. A retractable cover blocks the fiber optic input surface during a non-working mode, and allows access for identification during a working mode. A light source having a plurality of light emitting diodes provides light that diaphans a portion of the finger. Several successive frames of image signals allow for biometric detection and verification of a human pulse to ensure the finger is not a counterfeit.

In a camera system according to the present invention, a lens controller obtains an exposure synchronizing signal that is generated by a camera controller from a camera body, causes a configuration formed of a first encoder, a second encoder and a counter to detect the position of a focus lens according to the obtained exposure synchronizing signal, and notifies the camera body of the detected position of the focus lens. The camera controller associates the position of the focus lens or the mechanism member obtained from the lens controller with an AF evaluation value based on the exposure synchronizing signal, and controls an autofocus operation of the camera system based on the position and AF evaluation value that are associated with each other. With this configuration, it is possible to improve the accuracy of an autofocus operation with a contrast system.

Systems including projection mechanisms, screens, and eyeglasses are detailed. The systems significantly reduce perceptible ghosting even when high contrast images (such as dark figures against a white background) are projected.

The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging. The biopsy site marker may be accurately fixed to the biopsy site so as to resist migration from the biopsy cavity when a placement instrument is withdrawn, and when the marked tissue is subsequently moved or manipulated.

A trim retarder for a liquid crystal display based projection system including a light source, a polarizer / analyzer, a liquid crystal display panel, and a projection lens, is clocked to an optimal azimuthal angle that provides a system contrast level substantially unaffected by the orientation of the slow axis of the liquid crystal display panel.

Provided is a method for rapid, 3D, dynamic, projection reconstruction bilateral breast imaging using simultaneous multi-slab volume excitation and radial acquisition of a contrast enhanced bilateral image, in conjunction with SENSE processing, using k-Space Weighted Image Contrast (“KWIC”) filtering and multi-coil arrays for signal separation in an interleaved bilateral MR bilateral breast scan that uses conventional Cartesian sampling without parallel imaging. Software was developed for the reconstruction, modeling contrast kinetics using a heuristic model, display by parametric mapping and viewer / analysis of the multidimensional, high frame-rate bilateral breast images.

A portable, lightweight digital imaging device uses a slit scanning arrangement to obtain an image of the eye, in particular the retina. The scanning arrangement reduces the amount of target area illuminated at a time, thereby reducing the amount of unwanted light scatter and providing a higher contrast image. A detection arrangement receives the light remitted from the retinal plane and produces an image. The device is operable under battery power and ambient light conditions, such as outdoor or room lighting. The device is noncontact and does not require that the pupil of the eye be dilated with drops. The device can be used by personnel who do not have specialized training in the eye, such as emergency personnel, pediatricians, general practitioners, or volunteer or otherwise unskilled screening personnel. Images can be viewed in the device or transmitted to a remote location. The device can also be used to provide images of the anterior segment of the eye, or other small structures. Visible wavelength light is not required to produce images of most important structures in the retina, thereby increasing the comfort and safety of the device. Flexible and moderate cost confocal and fluorescent imaging, multiply scattered light images, and image sharpening are further functionalities possible with the device.

An autofocus system for a camera includes a contrast focus detector which detects a position of a focusing lens group, at which the contrast of an object image reaches a maximum as a contrast in-focus position; a phase-difference focus detector which separates the object image light bundle into two light bundles which form two object images on a light-receiving element to detect a phase difference between the two object images formed thereon, the phase-difference focus detector defining a position of the focusing lens group at which an in-focus state is obtained for the object as a phase-difference in-focus position; and a controller for moving the focusing lens group via the lens driver to the phase-difference in-focus position or the contrast in-focus position. The controller adjusts a moving range of the focusing lens group in accordance with a degree of reliability of the phase-difference in-focus position.

Methods and apparatus for measuring perfusion using transmission laser speckle imaging are provided. The apparatus comprises a coherent light source and a detector configured to measure transmitted light associated with an unfocused image at one or more locations. The coherent light source and detector are positioned in a transmission geometry. The apparatus further comprises means for securing the coherent light source and the detector to the tissue sample in a fixed transmission geometry relative to the tissue sample. The apparatus may further comprise at least one processor to receive information from the detector and process detected variations in transmitted light intensity to determine a single metric of perfusion. The method may comprise the steps transilluminating a tissue sample with coherent light, recording spatial and / or temporal variations in the transmitted light signal, determining speckle contrast value(s), and computing a metric of perfusion.

An optical system for imaging the features, ridges, and height variations of an object by exploiting the properties of specular reflection of light to maximize the contrast of the features, ridges, and height variations. The system provides a non-contact method of imaging objects suitable for biometric identification, such as the imaging of fingerprints. The system obtains the strong specular reflection using a properly shaped wave front. Optionally, the system can include a polarizer that filters and thereby enhances the specular reflection from the surface. Optionally, the system can also include pre-processing means for adjusting image brightness, contrast, and magnification.

A medical ultrasonic imaging system transmits a set of two or more substantially identical transmit pulses into a tissue containing a contrast agent. The associated received pulses are filtered with a broadband filter that passes both the fundamental and at least one harmonic component of the echoes. The filtered received pulses are then applied to a clutter filter that suppresses harmonic and fundamental responses from slowly moving and stationary tissue, while clearly showing contrast agent response due to the loss of correlation effect. The disclosed system includes other signal paths for generating conventional B-mode images as well as combined images that include both components from the contrast-specific image as well as components from the B-mode image. An improved user interface allows the user to switch among these three images. Preferably the transmitter generates transmitted pulses having two or more spatially distinct focus zones, thereby improving the uniformity of contrast agent imaging over the imaged region.

The invention discloses a method for detecting fatigue driving. The method comprises the following steps: using a rectangular characteristic template in eye image areas of a driver to analyze the eyes so as to obtain upper eyelid lines; judging the closing states of the eyes according to curvatures or curvature characteristic values of the upper eyelid lines; counting the closing states of the eyes; and judging whether the driver is in a fatigue state or not according to a counting result. In the method, the opening and the closing of the eyes are judged according to the shapes of the upper eyelids, and because the relative contrast of the upper eyelid lines is stronger, the upper eyelid lines are more resistant to interferences. Moreover, the upper eyelid lines have better adaptability to expression changes, thus the judging result is more accurate.

Disclosed is a three-dimensional liver CT image automatically segmenting method based on hyper voxels and the graph cut algorithm. The method comprises analyzing a volume data histogram to adaptively enhance the image contrast; performing primary liver contour segmentation layer by layer through an adaptive threshold and an morphological method, selecting the largest liver segment to compute and extract a liver interest area; selecting seed points on the largest liver segment according to a primary liver contour, modelling foreground and background colors through a Gaussian mixed model; generating hyper voxels on the contrast-enhanced liver interest area through an SLIC (simple linear iterative clustering) algorithm, structuring an undirected weighted graph by taking the hyper voxels as the vertex, and segmenting the undirected weighted graph through the graph cut algorithm; performing postprocessing on segmentation results through a morphological algorithm. The three-dimensional liver CT image automatically segmenting method based on the hyper voxels and the graph cut algorithm can achieve rapid and accurate automatic segmentation of the liver in a three-dimensional abdominal CT image.

An edge-preserving diffusion filter maintains the sharp edges in images while smoothing out image noise. An edge-preserving diffusion filter applies an edge-preserving smoothing filter to an image to form a filtered image. The modified image is then blurred by a blurring filter to form a blurred image. The modified image and the blurred image are blended together to form an output image based on an error metric associated with each pixel. The edge-preserving diffusion filter may be utilized to perform a multilevel decomposition of the image. The edge-preserving diffusion filter may be applied to an unfiltered image to produce a base image. The difference between the unfiltered image and the base image defines a detail image. The detail image may be used as the input for recursively generating additional levels of detail. The multilevel decomposition may utilize filter kernels associated with different contrast levels for each iteration.

The invention discloses a reflective panoramic imaging system and method. The reflective panoramic imaging method comprises the following steps: directly mounting an optical system on an image sensor or an existing camera optical system, and respectively locating image planes of two groups of fisheye lenses on the image sensor through a reflection element in a non-overlapped manner; selecting a camera to enter a shooting mode; dividing images formed by light on the image sensor after passing by the first fisheye lens and the second fisheye lens; respectively processing the divided images, comprising image correction, color adjustment, noise elimination, exposure and contrast adjustment; extracting, screening and matching feature points of the images; carrying out image registration, splicing and fusion; selecting the shooting mode, and compressing and storing a panoramic image and a panoramic video; and selecting a preview mode, rendering the spliced panoramic image, and displaying the panoramic image on a device connected to the camera. The reflective panoramic imaging method disclosed by the invention can be used for shooting a complete panoramic image, guaranteeing the synchronism of video steam and obtaining the panoramic video more easily.

A method for the real-time visualization and detection of extravasated and or infiltrated fluid and substances, including blood, that occur near the cannulation site of an injection is described wherein illumination or transillumination with near infrared light is used to image the contrast in real-time between absorbing and nonabsorbing subdermal and intradermal structures of blood vessels and remaining surrounding tissue, foreign substances and other structures in order to establish a baseline image of the body area of interest, and any new image is monitored and compared with the baseline image to detect the extravasation and / or infiltration of fluids and substances, including blood, around a vein or artery into the subdermal or intradermal tissue.

The invention is directed biopsy site markers and methods of marking a biopsy site, so that the location of the biopsy cavity is readily visible by conventional imaging methods, particularly by ultrasonic imaging. The biopsy site markers of the invention have high ultrasound reflectivity, presenting a substantial acoustic signature from a small marker, so as to avoid obscuring diagnostic tissue features in subsequent imaging studies, and can be readily distinguished from biological features. The several disclosed embodiments of the biopsy site marker of the invention have a high contrast of acoustic impedance as placed in a tissue site, so as to efficiently reflect and scatter ultrasonic energy, and preferably include gas-filled internal pores. The markers may have a non-uniform surface contour to enhance the acoustic signature. The markers have a characteristic form which is recognizably artificial during medical imaging. The biopsy site marker may be accurately fixed to the biopsy site so as to resist migration from the biopsy cavity when a placement instrument is withdrawn, and when the marked tissue is subsequently moved or manipulated.

The invention discloses a panorama shooting method based on a mobile platform, comprising steps of turning on a preposition camera and a postposition camera, reading images or video flows and real-time preview video flows of the preposition camera and the postposition camera, performing respective processing on two paths of images, wherein the processing comprises image correction, color regulation, noisy point elimination, exposure and contract ratio regulation, extracting, screening and matching the image characteristic points, rectifying, splicing and fusing the image, compressing and storing the panorama images and videos, and rendering the image and displaying the image on the mobile phone. The panorama shooting system comprises two fish eye lenses and one reinforcing mechanism; the two fish eye lenses are installed on the mobile phone or on the preposition camera and the postposition camera of a flat computer through the reinforcing mechanism. The invention discloses a panorama shooting system based on the moving platform and the method, which better solve the problems that the current panorama shooting method is high in the cost and complex in the shooting process, needs the independent shooting device and cannot record the panorama videos.

A method, apparatus, and software for exercising human eyes with a monitor onto which is projected a plurality of shapes such that portions of the shapes have a contrast changing at a speed less than or equal to approximately 2.0 cycles / sec. The shapes comprise paired shapes of opposite colors (black / white, red / green, or blue / yellow, or combinations thereof), and the speed is preferably less than or equal to approximately 0.8 cycles / sec. Also a method, apparatus, and software projecting a plurality of symbols each comprising a plurality of bars one of which has a length different than that of others in the symbol. A visual efficiency is calculated based upon a number of identical symbols correctly located by a user and a time to locate the identical symbols.