557 results about "Modulation transfer" patented technology

A system and method for determining the temporal resolution of a tomographic imaging device uses an apparatus to drive one or more dynamic phantoms composed of multiple materials. The apparatus is placed at or near the isocenter of the imaging device and the one or more phantoms are moved to produce a plurality of dynamic features, each having a specified frequency. The dynamic features are imaged with the device and the acquired image data corresponding to the dynamic features is analyzed to determine a temporal modulation transfer value at each of the known specified frequencies. The temporal resolution of the imaging device is determined using these temporal modulation transfer values.

Electronic displays are provided which can reproduce image data with high contrast ratios and a gray scale range comparable to conventional X-ray film viewed on a light box. One such display includes a rear low-resolution LCD or DLP display which projects an image onto a high-resolution LCD display. In such embodiments, the mechanical and optical registration between the two displays is not critical. Therefore, modulation transfer function and distortion of the projection optics are not critical. Accordingly, the brightness of the inventive display can be maximized with high power lamps and high aperture projection optics. Because the display has a high dynamic range, the need for dynamic range compression algorithms is reduced.

Optical properties with high non-linearity such as a modulation transfer function (MTF) are efficiently optimized at high speed compared to conventional methods. An optimal solution of an optical system is obtained in a first optimization unit using a merit function on aberration. Weights or target values of the merit function on aberration is automatically adjusted in a second optimization unit in a manner that an evaluated value of the MTF or the like approaches a desired value. The first optimization unit re-optimizes the optical system using the weights or target values which have been automatically adjusted. Thus, automated is a function equivalent to the operation which has been conducted by a designer such as adjustment to weights or target values.

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.

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.

The invention discloses a device for measuring a modulation transfer function of an optical system and a method thereof. A target generator of the device comprises a knife edge target (4), a light source (1) and an electrical machine (3), wherein the electrical machine drives the knife edge target (4), so that an inclined angle beta is formed between the arrangement direction of a knife edge pixel (12) of the knife edge target (4) and that of a pixel (13) of an area array detector, and the inclined angle meets the following condition: ds=d sin beta, wherein the ds is a sampling distance, and the d is the size of the edge length of the pixel of the area array detector. When measuring, the modulation transfer function, the electrical machine drives the knife edge target (4) to rotate at the angle of beta to perform image data collecting and data processing so as to obtain modulation transfer function of the optical system to be measured. The invention adopts the knife edge target to realize an oversampling technology and improve the sampling rate, thereby being capable of measuring the modulation transfer function of the optical system to be measured without a relay amplifying system, being capable of measuring the maximum frequency which is higher than the Nyquist frequency of the area array detector, simplifying a measuring system, and avoiding complex assembling and correcting work when manufacturing apparatuses.

The invention discloses an optical imaging system. The optical imaging system comprises an imaging lens group and an image sensor. The imaging lens group comprises at least three lenses with refraction power, a first imaging surface and a second imaging surface. The image sensor is arranged between the first imaging surface and the second imaging surface. The first imaging surface is a visible light image plane specifically vertical to an optical axis. Additionally, the center visual field of the first imaging surface has the maximum value of modulation transfer factor with first space frequency. The second imaging surface is an infrared light image plane specifically vertical to the optical axis. Additionally, the center visual field of the second imaging surface has the maximum value ofmodulation transfer factor with first space frequency. When a specific condition is met, the distance relative to the imaging focal length of visible light and the distance relative to the imaging focal length of infrared light are reduced. Meanwhile, imaging quality of visible light and infrared light is enhanced.

The invention discloses an aberration-free image reconstruction method based on CCD array pixel response function frequency domain calibration, and belongs to the technical field of detectors. A frequency domain model of pixel response functions is established, same-frequency lasers with high stability are utilized for generating sinusoidal interference fringes in a far field, fringe light fields at different spatial frequencies are acquired by changing the relative positions of the same-frequency lasers, frequency domain calibration is conducted on the pixel response functions, calibration coefficients in all orders of all the pixel response functions are acquired respectively, on the basis and in combination with a Fourier optics method, CCD imaging reconstruction is achieved, and aberration-free imaging of a CCD detector can be achieved. According to the method, the pixel frequency domain response functions can be calibrated, meanwhile, tiny offset of the relative positions of all pixels can be calibrated, reconstructed images are free of sample blurs, modulation transfer functions (MTF) approach 1, the contrast ratio is not decreased, and the aberration-free image reconstruction method has the advantages of being high in calibration accuracy and wide in application prospect.