240 results about "Quality of vision" patented technology

The present invention discloses a system and method for rate control of MPEG video streams to achieve a target bit rate in a transcoder at the best visual quality possible. The invention monitors video buffer fullness for selecting the amount of rate reduction necessary to achieve a target bit rate. The invention also utilizes a method for selective requantization of DCT coefficients to assure visual quality.

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.

A method of measuring eye refraction to achieve desired quality according to a selected vision characteristics comprising the steps of selecting a characteristic of vision to correlate to the desired quality of vision from a group of vision characteristics comprising acuity, Strehl ratio, contrast sensitivity, night vision, day vision, and depth of focus, dynamic refraction over a period of time during focus accommodation, and dynamic refraction over a period of time during pupil constriction and dilation; using wavefront aberration measurements to objectively measure the state of the eye refraction that defines the desired vision characteristic; and expressing the measured state of refraction with a mathematical function to enable correction of the pre-selected vision characteristic to achieve the desired quality of vision. The mathematical function of expression may be a Zernike polynomial having both second order and higher order terms or a function determined by spline mathematical calculations. The pre-selected desired vision characteristics may be determined using ray tracing technology.

A vision metric, called the sharpness metric, indicates the subjective sharpness of a patient's vision by taking into account both the wavefront aberration and the retinal response to the image. A retinal image quality function such as the point spread function is convolved by a neural quality function, and the maximum of the convolution over the retinal plane provides the sharpness metric. The sharpness metric can be used to control eye surgery or the fabrication of a lens.

The present invention relates generally to the restoration or improvement of the quality of human vision and, more particularly to a self-adapting system and method for achieving automatic sharp vision by the human eye of objects for instance at distances between 25 cm and more than 10 meters away. The invention can be situated in at least four technological domains: 1. ophthalmology, in particular the implantation of intraocular lenses. 2. Non-contact biometric signal recording and processing. 3. Electro-optic control of refractive lens power. 4. Wireless energy transfer.

Tear film stability has an important role in the quality of vision. A system and method for performing Fluctuation Analysis of Spatial Image Correlation (FASIC) provides for a non-invasive system and method for evaluating the dynamics of the tear film surface using spatial autocorrelation analysis. With FASIC, a series of images are obtained using illumination and a camera. The spatial autocorrelation is calculated for image frames produced by the camera. A sinusoidal background appears in this correlation together with other features. The changes in the sinusoidal background of the spatial autocorrelation is extracted and monitored over time. The spatial period of this sinusoidal background correlates with the thickness of the tear film. In this regard, one is able to derive the tear film thickness from the period of this sinusoidal background.

The invention carries out process in frame for image; then carries out process inter frame for continuous three frames of image, which are processed in frame. The method includes following steps: using Laplace operator to carry out edge detection for image so as to obtain edge information of each pixel; if a pixel is an edge pixel or its more than two neighbor pixels in four pixels around are as edge pixels, then value of the pixel is saved; otherwise, carrying out filtering process for the pixel by using median filter; based on difference between adjacent frames, movement detection is carried out to determine whether pixel in the current frame is moved; if yes, the value is saved; if no, then result of median filter for corresponding points in three frames is as result of filtering the pixel. The invention protects details of image and sharpness furthest so as to raise vision quality of output image.

The invention discloses a method for achieving global illumination drawing of an animation three-dimensional scene with virtual point light sources, and belongs to the technical field of three-dimensional animation drawing. According to the method, geometric objects in the scene are divided into the static geometric objects and the dynamic geometric objects, and organization and management are respectively carried out with different scene graphs. On the basis that light sampling is carried out on illumination emitting space of the light sources, intersection points of light and the geometric objects in the scene are solved, the virtual point light sources are created at the positions of the intersection points to illuminate the animation three-dimensional scene, and indirect illumination drawing of the animation three-dimensional scene is further achieved. By means of the method, the large number of virtual point light sources can be reused between continuous frames, and global illumination drawing of the animation three-dimensional scene with viewpoints and geometric object movement can be supported at the same time. The method is used for producing three-dimensional animations, and the visual quality of the three-dimensional animations can be improved.

The embodiments herein provide a pupil centered and fovea focused optics assembly comprising a ring platform provided inside a capsular bag of a mammalian eye to support an intraocular lens. The optical center of the intraocular lens is decentered with respect to the geometric center of the intraocular lens to align the optical centre of the lens with a visual axis of a pupil of the mammalian eye to improve the visual quality and to prevent an aberration. A plane of the intraocular lens is turned and tilted through a preset angle to point an optic axis of the intraocular lens to the Fovea.

The present invention describes a multi-focal intraocular lens for the human eye. The intraocular lens of the present invention provides improved vision quality over a range of object distances without producing glare or halos. It also provides non-symmetric, or nearly symmetric, optical zones about the lens optical axis.

The invention relates to a reading desk lamp evaluation method based on an ergonomic experiment. The reading desk lamp evaluation method comprises the steps of performance evaluation of average illumination and correlated color temperature, comfort level evaluation of average illumination and correlated color temperature, illumination uniformity evaluation, reflected glare evaluation, direct glare evaluation and color rendering property evaluation; an evaluation system is formed by outputs of respective evaluation scores of the six aspects and the weighted average of the evaluation scores; the establishment of performance evaluation of average illumination and correlated color temperature is based on a visual performance experiment; the establishment of comfort level evaluation of average illumination and correlated color temperature is based on a Christopher illumination-color temperature comfort curve; the establishment of illumination uniformity evaluation is based on a national standard; the establishment of reflected glare evaluation is based on a veiling reflected glare reception evaluation experiment; the establishment of direct glare evaluation is based on a national standard; and the establishment of color rendering property evaluation is based on quality factor (QF) indexes in a color quality grade drafted by American national standard institute. By adopting the reading desk lamp evaluation method, the relation between physical parameters and vision quality is established, a quality evaluation result can be output only by measuring the physical parameters of the reading desk lamp, the assessment routine is simplified, and the objectivity and the accuracy are higher.

A binocular vision apparatus allows a patient to view objects through the apparatus with polychromatic light and monochromatic aberration correction, such that the chromatic aberration of the eye can be combined with the monochromatic aberration correction, so as to provide a more accurate determination of vision quality. The binocular vision apparatus provides left and right viewing optics that can substantially maintain the line of sight of each eye, such that objects can be viewed in a room with 3D depth perception corresponding to the distance of the object from the patient. As both near and far objects can be viewed with binocular aberration correction, the patient can alternate binocular viewing between near and far vision with chromatic aberration so as to evaluate a proposed treatment such as a presbyopia correction.

The invention relates to a drug sustained-release microsphere capable of being embedded in intraocular lens loop and a preparation method of the drug sustained-release microsphere. The drug sustained-release microsphere prepared by the provided method can be used for effectively preventing and treating microorganism infection and antagonistic inflammatory reaction after a cataract surgery, reducing the occurrence rate of intraocular inflammation infection after the cataract surgery, and preventing and inhibiting after-cataract, so as to improve visual quality after the surgery. The technical scheme is that according to the drug sustained-release microsphere capable of being embedded in the intraocular lens loop, the drug sustained-release microsphere is formed by mixing drugs and a carrier at the ratio of 1 to (10000-1), and the drug sustained-release microsphere is 100-800mm in diameter. The preparation method of the drug sustained-release microsphere capable of being embedded in the intraocular lens loop sequentially comprises the following steps: (1) mixing the drugs and the carrier according to the ratio and stirring to obtain mixed liquid; (2) condensing fog-like materials in a collecting room to obtain microspheres; and (3) collecting the microspheres and screening the microspheres by virtue of a screen to obtain the microspheres with required diameters; disinfecting, sealing and packaging the microspheres.

The parameters of an optical code are optimized to achieve improved signal robustness, reliability, capacity and/or visual quality. An optimization program can determine spatial density, dot distance, dot size and signal component priority to optimize robustness. An optical code generator employs these parameters to produce an optical code at the desired spatial density and robustness. The optical code is merged into a host image, such as imagery, text and graphics of a package or label, or it may be printed by itself, e.g., on an otherwise blank label or carton. A great number of other features and arrangements are also detailed.

The invention discloses a multi-resolution JND (Just Noticeable Difference) model building method based on visual perception. The method comprises the steps of: 1. arranging a group of balanced multi-wavelet filters, and carrying out multi-channel wavelet decomposition on an input image through the group of balanced multi-wavelet filters; 2. respectively calculating a basic JND threshold, a luminance masking factor and a contrast masking factor of a luminance layer and a chroma layer, so as to simulate a space contrast sensitive function effect, a luminance self-adaptive masking effect and a contrast masking effect; and 3. respectively calculating to obtain a multi-resolution JND model based on visual perception by utilizing the luminance layer and the chroma layer. According to the multi-resolution JND model building method based on the visual perception, the characteristics of the human visual system are effectively simulated, and the multi-channel decomposition, the space contrast sensitive function effect, the luminance self-adaptive masking effect, the contrast masking effect and the like are compressively taken into account, so that the multi-resolution JND model based on the visual perception can be built; and the model can inject multiple noises, and also can keep the image to be in high visual quality after the noises are injected.

The invention discloses a stereoscopic video objective quality evaluation method based on machine learning. When spatial domain quality of luminance component images of single-frame images is evaluated, each image block of luminance component images of each frame of image in original and distorted stereoscopic videos is subjected to singular value decomposition, and dot product of singular vectors obtained from singular value decomposition is adopted to evaluate distortion degree of each frame of image in the distorted stereoscopic video. Because the singular vectors can greatly reflect structural information of images, when the dot product of the singular vectors is adopted to evaluate the quality of the images, changes of the structural information are considered, and therefore, evaluation results can reflect changes of visual quality of the stereoscopic video more objectively when the stereoscopic video is under various kinds of distortion influences. According to the stereoscopic video objective quality evaluation method based on machine learning, a method of machine learning is adopted to process the relations between objective quality evaluation predicted values and the quality of a left-view point video and a right-view point video, and degree of difference among point views of the left-view point video and the right-view point video, and therefore, evaluation results which are more consistent with human visual perception can be effectively obtained.