553 results about "Modulation transfer" patented technology

The present invention provides an intraocular lens (IOL) having an optic with a posterior and an anterior refractive surfaces, at least one of which has an aspherical profile, typically characterized by a non-zero conic constant, for controlling the aberrations of a patient's eye in which the IOL is implanted. Preferably, the IOL's asphericity, together with the aberrations of the patient's eye, cooperate to provide an image contrast characterized by a calculated modulation transfer function (MTF) of at least about 0.25 and a depth of field of at least about 0.75 Diopters.

Methods and systems for inspecting a reticle are provided. A method may include forming an aerial image of the reticle with an inspection system at a wavelength different from a wavelength of an exposure system. The method may also include correcting the aerial image for differences between modulation transfer functions (MTF) of the inspection system and the exposure system. In this manner, the corrected aerial image may be substantially equivalent to an image of the reticle that would be printed onto a specimen by the exposure system at the wavelength of the exposure system. In addition, the method may include detecting defects on the reticle using the corrected aerial image. The detected defects may include approximately all of the defects that would be printed onto a specimen by the exposure system using the reticle.

(A2) An extended depth of field (DOF) imaging system (10) is disclosed that has a corresponding extended depth of focus (DOF′) by virtue of its optical system (20) having a select amount of spherical aberration. The imaging system has an image processing unit (54) adapted to process the raw images and perform contrast enhancement to form processed images. The image processing includes restoring the defocused modulation transfer functions (MTFs) using a gain function (G) and the amount of defocus. The imaging system can include an illumination system (60) that illuminates the object being imaged to establish a distance (DH) between the optical system and the object, where distance DH is used in the restoring of the MTF. An iris-recognition (I-R) system based on the enhanced DOF imaging system is also disclosed.; Optical system embodiments for use in the DOF imaging system that can provide select amounts of spherical aberration—and thus select increases in DOF—without increasing the adverse impact of other aberrations on image formation are also disclosed.

A method of determining the lower limit of decoding resolution in a digital imaging-based bar code symbol reader. A software-based optical design program is used to generate the composite DOF chart of image formation optics employed in the digital imaging-based bar code symbol reader. The modulation transfer function (MTF) of the object image is used to determine the smallest mil size code that can be decoded, at a given object distance, to produce an optical performance curve. The program calculates the size of the field of view (FOV) of a single sensor pixel, when projected through the image formation optics and out into object space. For both the 1.4 and 1.6 sampling limit pixel rules, the calculated FOV values are plotted on the same axes as the optical performance curve. Using graphical solution techniques, the sampling limit line of choice determines the lower limit of the decoding resolution in the imaging-based bar code symbol reader.

Imaging systems and methods are provided. One exemplary system incorporates multiple lenses that are individually configured to receive multi-wavelength light from an object to be imaged. Each lens provides an optimal modulation transfer function (MTF) for an individual wavelength contained in the multi-wavelength light when this individual wavelength of light strikes the lens at a particular incident angle. Associated with each lens is a color filter and a sensor. The color filter receives the multi-wavelength light from the lens, and transmits the individual wavelength of light on to the sensor. The image signals obtained from each of the multiple sensors are combined to generate an image of the object.

The invention relates to a dynamic object modulation transfer function measuring method and a device thereof, pertaining to the optical property measurement field. The invention aims at providing a dynamic object modulation transfer function measuring method and a device thereof which can carry out the dynamic object modulation transfer function measurement under different fields of view, namely, uniform linear motion, uniformly-accelerated rectilinear motion, simple harmonic motion, but also can measure static target modulation transfer function and separate the static target modulation transfer function from whole machine modulation transfer function. The device consists of a light source, a collimating lens, a pupil coupling system and an electro-optical imaging system which are arranged along the ray propagation direction in sequence; the electro-optical imaging system carries out imaging towards the light source moving along the guide rail direction and line spread function is obtained from the image and carried out one-dimensional Fourier transformation so as to obtain the dynamic object modulation transfer function. The method and the device of the invention are not only suitable for static image evaluation field but also for the image evaluation field of dynamic object imaging by a time-delay electro-optical imaging system.

Methods, devices, and systems establish an optical surface shape that mitigates or treats a vision condition in a patient. An optical surface shape for a particular patient can be determined using a set of patient parameters for the specific patient by using a compound modulation transfer function (CMTF). The compound modulation transfer function can include a combination of modulation transfer functions (MTF's) at a plurality of distinct frequencies.

Zoom lens systems and methods for imaging incoming rays over a range of ray angles are disclosed. The incoming rays are characterized by at least phase. The zoom lens system includes an optical axis and is characterized by a plurality of modulation transfer functions (MTFs) corresponding at least to the range of ray angles. The zoom lens system includes an optical group disposed along the optical axis, including at least one variable optical element that has a variable focal length selectable between at least two distinct focal length values. The optical group also includes a wavefront coding element. The wavefront coding element alters at least the phase of the incoming rays, such that the plurality of MTFs corresponding to the range of ray angles, for each one of the two distinct focal length values, are less sensitive to misfocus-like aberrations than a corresponding system without the wavefront coding element.

The invention provides an image modulation transfer function (MTF) evaluation-based module motor curve testing method. An MTF capable of reflecting a defocusing change condition of a lens and testing the consistency of motor characteristics is used as a definition calculation function, MTFs of different positions of a motor are analyzed according to a motor curve fitted by the MTFs, the kinetic characteristics of the motor are judged, and when the motor curve is tested, the positions of the highest points of the motor curve in four corners of a displayed image are simultaneously found, the positions of the four corners are calculated to obtain focal length differences of the four corners, a tilting height difference of the lens and the surface of a sensor is judged, and a tilting angle is calculated. According to the motor curve testing scheme applied by the invention, an MTF testing target and image detection equipment are used for effectively detecting the motor characteristics of a module and bad conditions of tilting of the motor, so that the quality of the product is ensured.

The invention relates to a device and method for measuring a modulation transfer function of an optical lens based on an infinite conjugate optical path. The method comprises the following steps: installing a slit target; enabling a to-be-measured lens to be placed in a lens pallet, and placing the lens pallet on a two-dimensional platform; turning on an LED light source, so as to provide illumination for a testing system; searching an optimal focal plane of the to-be-measured lens, and determining the accurate placement position of a slit; adjusting the specific position of an image collection unit, and obtaining the optimal photographing azimuth of a slit image; photographing the tilt image through the to-be-measured lens, and transmitting the slit image to a computer; processing the slit image and obtaining an MTF curve of the to-be-measured lens; precisely controlling the position of the tilt target and the position of the lens pallet through a motor controller, and achieving the continuous online testing of an MTF value of the to-be-measured lens on the computer platform. The method and device can be used for measuring the lens with a big field angle, and solve problems that a conventional infinite conjugate optical system and a conventional edge method are large in optical lens error and poor in stability.

A method and system for estimating motion blur of an image associated with a moving object. The direction of one-dimensional motion blur may be estimated by inspecting a power spectrum associated with the image. A radon transform with respect to the image power spectrum is computed in the direction of the motion blur. A family of kernels with respect to the one-dimensional motion blur may then be defined utilizing a shutter triggering sequence associated with an image capturing device. The family of kernels may be modeled utilizing a modulation transfer function (MTF). Each modulation transfer function may be compared with the radon transform of the power spectrum associated with the image via a correlation function. The kernel with highest correlation with respect to the radon transform of the image power spectrum may be employed for de-blurring the image.

A method for determining a refractive correction for an eye involves measuring an optical error of the eye, calculating at least one image quality parameter for a selected spatial frequency of range of spatial frequencies, based on the measured optical error of the eye, and forming a plan for refractive correction of the optical error, based on the calculated image quality parometer. In some embodiments, measuring the optical error involves taking one or more wavefront measurements. In some embodiments, calculating the parameter involves calculation a modulation transfer function.

An image pick-up optical lens assembly, sequentially arranged from an object side to an image side along an optical axis, comprises: a first lens element with a positive refractive power having a convex object-side surface, a second lens element with a negative refractive power, a third lens element with a positive refractive power, a meniscus fourth lens element with a positive refractive power having at least one aspherical optical surface, and a fifth lens element with a positive refractive power having at least one inflection point on the optical image-side surface. Additionally, the image pick-up optical lens assembly satisfies several particular conditions. The invention possesses features such as good aberration compensation, well-performed modulation transfer function and short total length of lens assembly applicable for compact cameras and mobile phones.

A method for the simulation of responses of a nonlinear amplifier provides for measuring characteristics of nonlinearity of amplitude and of amplitude/phase-shift conversion of the amplifier, each measurement being made at an amplitude that is constant in input. The method further includes measuring the characteristics at different frequencies, developing the characteristics in sequences of direct transfer functions, computing frequency correctors for the direct transfer functions, measuring characteristics of distortion of amplitude modulation, each measurement being performed by modulating the input amplitude, computing modulation transfer functions reproducing the distortion amplitudes at output according to the input modulation amplitudes and correcting the direct transfer functions when the input amplitude is modulated in order to simulate the envelope memory effect. There is a direct application of the invention to the field of the simulation of high efficiency microwave amplification.

The invention discloses a CCD chip modulation transfer function test device and method. The CCD chip modulation transfer function test device mainly comprises a He-Ne laser, an adjustable attenuator, a beam expander, a pinhole filter, a diaphragm, a collimating lens, an improved Michelson interferometer, a camera obscura, an image capture card and a PC data processing system, wherein the He-Ne laser, the adjustable attenuator, the beam expander, the pinhole filter, the diaphragm and the collimating lens are arranged on the incident light path of the improved Michelson interferometer in sequence, and the optical axis of the He-Ne laser, the optical axis of the adjustable attenuator, the optical axis of the beam expander, the optical axis of the pinhole filter, the optical axis of the diaphragm and the optical axis of the collimating lens are arranged on the same straight line, the camera obscura is arranged on the emergent light path of the improved Michelson interferometer, and the PC data processing system is connected with the image capture card which is arranged in the camera obscura and is connected with a CCD. Incident light is processed through the CCD chip modulation transfer function test device to form parallel light, and goes out in a sine interference fringe mode through the improved Michelson interferometer, a sine interference fringe pattern is used as a target, imaging is carried out through the CCD, and a modulation transfer function of the CCD is obtained through a test by using the method of the ratio between the sine interference fringe contrast and the image contrast.

An enhanced spatial light modulator (ESLM) array, a microelectronics patterning system and a projection display system using such an ESLM for heat-minimization and resolution enhancement during imaging, and the method for fabricating such an ESLM array. The ESLM array includes, in each individual pixel element, a small pixel mirror (reflective region) and a much larger pixel surround. Each pixel surround includes diffraction-grating regions and resolution-enhancement regions. During imaging, a selected pixel mirror reflects a selected-pixel beamlet into the capture angle of a projection lens, while the diffraction grating of the pixel surround redirects heat-producing unused radiation away from the projection lens. The resolution-enhancement regions of selected pixels provide phase shifts that increase effective modulation-transfer function in imaging. All of the non-selected pixel surrounds redirect all radiation energy away from the projection lens. All elements of the ESLM are fabricated by deposition, patterning, etching and other microelectronic process technologies.

The invention relates to a method for detecting a modulation transfer function (MTF) of a hyperspectral remote sensing system based on an edge image. The method takes the influence of an image noise into consideration and comprises the following steps of: selecting edge areas in the horizontal direction and the vertical direction by calculating the modulation degrees of the edges of each wave band of a hyperspectral remote sensing image; performing differential operation on the edge areas to obtain linear spread functions; performing Gaussian function least squares fitting on the linear spread functions to obtain standard deviations; figuring the linear spread functions in the vertical direction and the horizontal direction out by using a median of the standard deviations of the linear spread functions in the vertical direction and the horizontal direction; performing discrete Fourier transform to obtain MTF curves in the two directions; and establishing a two-dimensional MTF matrix of the system by multiplying. The method can select suitable edge areas in the situation of a plurality of wave bands of the hyperspectral remote sensing image, and realize the extraction of the MTF ofthe system when the signal-to-noise ratio of the image is not high.

The invention discloses a determination method of an imaging condition of an agile satellite, comprising the following steps of: predicting and calculating three classic parameters which are MTF (Modulation Transfer Function), element resolution ratio and imaging width and are used for describing basic attributes, thereby determining the weight ratio accounted by all the parameters in an imaging condition determination system and finally determining the imaging condition of the agile satellite. In the determination method, the influence of imaging conditions of an agile satellite camera under various environments and working modes on imaging quality is considered comprehensively, comprehensive determination is carried out, design verification is carried out by utilizing ground simulation, a concise and objective decision-making basis is provided for a satellite user, meanwhile, the digging condition of specific imaging tasks is reflected to the satellite imaging capability. The determination method is the first comprehensive determination method for the imaging condition of the agile satellite in China, and therefore, the blank on the simulation analysis aspect of the satellite imaging condition in China is filled.