1121 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.

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.

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.

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 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 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.

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.

The invention relates to a method and an apparatus for creating facial images, more particularly to a composite picture system and method utilising a library of basic facial components. In typical composite picture systems, the process of creating facial images includes the steps of selecting various facial components, herein designated as basic morphological elements, from a library and assembling them. The novel method comprises the introduction of a component calibration step allowing the different basic morphological elements of a facial image to be merged into a single synthetic facial image with proportional components. A universal skin tone, created using a set of filters on the original images, is also used to reduce the contrasts between the individual basic morphological elements. In addition, each basic morphological element is encoded and uniquely describes each facial image. The use of the encoding facilitates the transmission of such images requiring only the code to be sent. The invention further provides a computer readable medium comprising a library of basic morphological elements and a program element that direct a computer to implement the composite picture process.

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.