31results about How to "Improve MTF" patented technology

A method for geometric calibration of a CT scanner, including, for each row of at least one row of detector cells, establishing a complete geometric description of the CT scanner, including at least one unknown geometric parameter, establishing a description of a forward projection function using the complete geometric description, acquiring actual projection coordinates of a calibration phantom placed in a scanning field of view (SFOV) on a current row of detector cells and corresponding to a plurality of angles, acquiring calculated projection coordinates of the calibration phantom on the current row of detector cells and corresponding to the plurality of angles using the description of the forward projection function, and acquiring a calibrated value for the at least one unknown geometric parameter by evaluating the at least one unknown geometric parameter based on the acquired actual projection coordinates and calculated projection coordinates via a nonlinear least square fitting algorithm.

The disclosure is directed at a method and apparatus for improving method and apparatus for improved modulation transfer function and detective quantum efficiency of X-ray detectors. The method and apparatus include digitizing microelement outputs obtained by micro sensor elements and the generating pixel outputs from these digitized microelement outputs. Each pixel output is the sum of a plurality of weighting factored microelement outputs.

A radiological image detection apparatus, includes: two scintillators that convert irradiated radiation into lights; and a photodetector arranged between two scintillators, that detects the lights converted by two scintillators as an electric signal; in which: an activator density in the scintillator arranged at least on a radiation incident side out of two scintillators in vicinity of the photodetector is relatively higher than an activator density in the scintillator on an opposite side to a photodetector side.

An image input apparatus that inputs an image of an object residing within a living body is disclosed. The image input apparatus includes a light source that irradiates near infrared light on the living body, a lens array arranged at a position facing the living body and including plural lenses each having a face with zero or negative power arranged at a side facing the living body and a face with positive power arranged at a side facing an image surface, an imaging unit arranged at the image surface side of the lens array that forms a compound-eye image corresponding to a collection of ommatidium images formed by the lenses of the lens array, and a reconstruction unit that reconstructs a single image from the compound-eye image using a parallax between the ommatidium images. The reconstructed single image is input as the image of the object.

An optical imaging assembly (22) having cylindrical symmetry, comprising a plurality of lenses having surfaces with curvatures and spacings between the surfaces, such that an optical image formed by the plurality of lenses has a defocus aberration coefficient greater than 0.1 at a focal plane of the assembly.

An optical imaging assembly having cylindrical symmetry, comprising a plurality of lenses having surfaces with curvatures and spacings between the surfaces, such that an optical image formed by the plurality of lenses has a defocus aberration coefficient greater than 0.1 at a focal plane of the assembly.

An image sensor comprises a semiconductor material having an illuminated surface and a non-illuminated surface; a photodiode formed in the semiconductor material extending from the illuminated surface to receive an incident light through the illuminated surface, wherein the received incident light generates charges in the photodiode; a transfer gate electrically coupled to the photodiode to transfer the generated charges from the photodiode in response to a transfer signal; a floating diffusion electrically coupled to the transfer gate to receive the transferred charges from the photodiode; and a near infrared (NIR) quantum efficiency (QE) and modulation transfer function(MTF) enhancement structure. The NIR QE and MTF enhancement structure comprises: a NIR QE enhancement sub-structure comprising at least one NIR QE enhancement elements within a photosensitive region of the photodiode, wherein the NIR QE enhancement sub-structure is configured to modify the incident light at the illuminated surface of the semiconductor material by at least one of diffraction, deflection and reflection, to redistribute the incident light within the photodiode to improve optical sensitivity, including NIR light sensitivity, of the image sensor; and a MTF enhancement sub-structure disposed on the non-illuminated surface of the semiconductor material, facing toward the NIR QE enhancement sub-structure, wherein the MTF enhancement structure has a geometry corresponding to the NIR QE enhancement sub-structure, to ensure the incident light is still within the photodiode after redistribution.

An optical imaging assembly having cylindrical symmetry, comprising a plurality of lenses having surfaces with curvatures and spacings between the surfaces, such that an optical image formed by the plurality of lenses has a defocus aberration coefficient greater than 0.1 at a focal plane of the assembly.

The invention relates to a phase mask plate optimal parameter acquisition method applied to a wavefront coding system. The method comprises the following steps that (1) three optimization objectives expected to be achieved are established, wherein the three optimization objectives expected to be achieved are OTF defocusing invariability, MTF defocusing invariability and PTF defocusing invariability; (2) Fisher information is calculated according to a defocused MTF, a defocused PTF and a defocused OTF respectively; (3) an objective function is established through weighting according to the Fisher information corresponding to the three objectives to be optimized; (4) a phase mask plate optimal parameter is acquired according to the objective function established in the step (3). The phase mask plate optimal parameter acquisition method is applied to the wavefront coding system, and the stability of the defocused PTF of the system can be improved through the method.

The invention discloses an optical system of an attitude sensor. A diaphragm of the optical system is arranged on the first surface of the quartz window plate glass of the optical system, which is beneficial to reducing the size of the optical system and eliminating parasitic light; and the optical system can simultaneously realize large field, large aperture and achromatism by utilizing four common optical materials and effectively shorten the size of the optical system by using a plurality of osculant positive and negative lenses to correct aberration. By adopting the layout mode, the optical system has higher MTF (modulation transfer function) while ensuring relatively uniform full field defocused spots, thereby being capable of giving consideration to both the optical imaging of a star sensor and the imaging of the optical sensor with high resolution requirements.

The invention discloses a single-degree-of-freedom self-adaptive balance assembly mechanism. The single-degree-of-freedom adaptive balance assembly mechanism includes: a precision platform, an adaptive balance device, a string, a bracket, and a position adjustment device; the mirror and the bracket are all arranged on the precision platform, and the The precision platform is a reference leveling; the self-adaptive balance device is connected to the support of the mirror; the position adjustment device is arranged on the support through the string, and the position adjustment device is connected to the The self-adaptive balancing device is connected, and the pulling force exerted by the position adjusting device on the string is equal to the sum of the gravitational force of the supporting member of the reflector and the self-adapting balancing device. The single-degree-of-freedom self-adaptive balance assembling mechanism provided by the invention can eliminate the influence of the support member of the reflector on the surface shape of the reflector during assembly.

An image intensifier is provided in which a thin film (090) is arranged between an output surface of the electron multiplier (040) and the phosphorous screen. The thin film is a semi-conductor or insulator with a crystalline structure comprising a band gap equal or larger than 1 eV, wherein the crystalline structure has a carrier diffusion length equal or larger than 50% of the thickness of the thin film. In addition, the thin film has an anode directed surface which has a negative electron affinity. By way of provisioning a thin film of the above type in the image intensifier, an improvement in mean transfer function of the overall image intensifier is obtained.

A restoration processing unit performs a restoration process based on an optical transfer function of an optical system for a target image. The entire angle of view of the optical system is greater than 90 degrees. A light amount evaluation region of the optical system is a region in which a distance from the center of an image formation plane is not less than 80% of half of the length of a diagonal line of an imaging surface of an imaging element. When a first evaluation wavelength is used, the ratio of the amount of light in the light amount evaluation region to the amount of light in a region of the optical system corresponding to the center of the image formation plane is not less than 25%. When a second evaluation wavelength is used, the value of the MTF of the optical system acquired at half of the Nyquist frequency of the imaging element is not less than 15%.