48results about How to "Realize imaging detection" patented technology

The invention discloses a spectral domain OCT detecting system and method based on segmented spectrum optical path coding. A dichroscope is arranged in a traditional reference arm, so that a light source spectrum is divided into two portions which arrive at a transmission light path and a reflection light path respectively. Due to the fact that the positions of plane mirrors in the transmission light path and the reflection light path are different, and the two portions of the spectrums cover different optical paths in the reference arm and interfere with returning light of two different depth sections in a sample. After the two portions of spectrum interference signals enter a detection arm, the spectrum interference signals are detected by pixel points in different regions of a CCD in a spectrometer, spectrum parallel obtaining is achieved on the non-aliasing condition. On the condition that the detection arm and a sample arm of spectrum domain OTC are not changed, a simple light splitting structure is additionally arranged in the reference arm, arrangement of different zero-optical-path positions in a sample and parallel detection of double reference arm spectrum domain OCT signals are achieved, and imaging range of the spectrum domain OCT is broadened.

The invention discloses an MIMO through-wall radar based single-side double-point squint imaging method of a building. An MIMO through-wall radar carries out real-aperture squint detection at two detection points selected in the single side of the building, and collected real aperture echoes of the two points from two squint images which include part corners of the building and static objects in the building via a backward projection imaging algorithm. Overlapped fusion and 2D constant false alarm detection are carried out on the two squint images, the integrity of all corner images of the building is ensured, the layout of all walls can be determined, corner image sidelobe and multipath phantom interference are inhibited, distribution of static objects therein can be determined, and a panorama image of the building including clear corner images and static object images is obtained finally. The corner image and the static object image can be used to determine the wall layer out and the static object distribution respectively, and imaging detection for the wall layout and the internal static objects of the building is realized.

The invention discloses an airborne dual-band photoelectric wide-area reconnaissance and tracking device. The device comprises a photoelectric turret (1); the photoelectric turret (1) comprises a visible light television (3), an infrared thermal imager (4), a gyro assembly (5), a servo module (6), an angle measuring module (9), a control management module (10), an image processing and tracking module (11) and a communication interface module (12); the servo module (6) is used for driving the line of sight of the photoelectric turret (1) to search or track a target; the angle measuring module (9) is used for measuring the angular position of the servo module (6), determining the real-time pointing direction of the line of sight; and the control management module (10) is used for controllingthe photoelectric turret (1) to be switched between a wide area search mode and a tracking monitoring mode, receiving the data of the image processing and tracking module (11) and the angle measuringmodule (9), performing data processing and sending processing results to the servo module (6) and the image processing and tracking module (11).

The invention discloses a method and a system based on double-space carrier frequency technology for increasing OCT (optical coherence tomography) imaging depth. Two reference arms different in optical path are arranged in a Fourier domain OCT system and interfere with sample light signals different in depth position. A scanning galvanometer system is arranged in each of the reference arms, so that incident positions, of light beam in the reference arms, on scanning galvanometers have different offset quantities relative to rotating shafts of the scanning galvanometers. The scanning galvanometers in a sample arm and the reference arms are enabled to scan synchronously through a synchronous control circuit. Due to space phase modulating effect of the scanning galvanometers in the reference arms, interference spectrum signals corresponding to two depth positions of a sample are loaded to different transverse space frequency spectrum bands respectively. Modulated interference spectrum signals which are detected are demodulated through a computer to acquire two OCT images corresponding to different depth positions of the sample, and multiple increase of OCT imaging depth can be realized through simple splicing.

The invention relates to a wavelength conversion system used for streak tube laser radar 3D multispectral sensing, in particular to a multispectral sensing wavelength conversion system based on an optical fiber array and belongs to the field of photo-electronic imaging. The multispectral sensing wavelength conversion system based on the optical fiber array comprises a receiving optical system, a spectro-grating, a spatial light modulator, the optical fiber array, a micro-lens array, a APD array, a transimpedance amplifier array, a differential receiving amplifier array, a vertical cavity surface laser array and a computer. The problem of manufacturing of a large-array detector is solved by introducing the spatial light modulator and the optical fiber array, and the crosstalk influence generated when all channels of a photo-electronic detector receive echo pulses is reduced. According to the multispectral sensing wavelength conversion system, the echo signals of different wavelengths are converted into peak-wavelength signals which a streak tube positive electrode material can respond to, multi-wavelength conversion for streak tube laser radar multispectral sensing is achieved, and the multispectral sensing wavelength conversion system can be widely applied to the multispectral 3D sensing imaging technology.

The invention provides a novel cross position-sensitive anode which is suitable for a micro-channel plate detector, and discloses a high-performance ultraviolet photon counting integral imaging detection system and a photon counting integral imaging measurement method, wherein the cross position-sensitive anode serves as a core detection component. The cross position-sensitive anode is divided into an upper layer and a lower layer, wherein each rectangular conductive strip on the upper layer is in overlap joint with each rectangular conductive strip on the lower layer, the rectangular conductive strips on the upper layer are parallel on the same plane, the rectangular conductive strips on the lower layer are parallel on the same plane, insulation layers correspond to the rectangular conductive strips on the upper layer in a one-to-one mode and are located in projection ranges of the corresponding rectangular conductive strips respectively, all the rectangular conductive strips on the upper layer and the lower layer integrally form a cross grid in the projection direction, and each rectangular conductive strip independently outputs an electric charge signal. The anode and the method can achieve the properties of high spatial resolution and high counting rate, solve the electrode conduction problems, reduce electrode crosstalk and accurately control the width of an insulation channel.

The invention discloses a large-view-field curved surface focal plane imaging method and system based on an image transmitting optical fiber bundle. The method comprises the following steps: incident light is incident to a Pitts universal plane generated by a spherical lens through the spherical lens formed by gumming two groups of symmetrical lenses; and after the light passes through an image transmitting optical fiber bundle input end arranged on the Pitts universal plane, the light is incident to a planar charge coupled device (CCD) array through an image transmitting optical fiber bundle output end coupled to the planar CCD array so as to realize curved surface focal plane imaging. By adopting the method and system disclosed by the invention, the imaging effects of a large view field and high resolution are realized, and the cost of a large-view-field imaging system is greatly reduced.

The invention relates to a power system fault detection system and method based on ultraviolet and infrared images. The system comprises an infrared camera, an ultraviolet camera and an upper computer. The infrared camera and the ultraviolet camera are arranged in front of a power device to be detected; light paths of the infrared camera and the ultraviolet camera are in parallel optical axis; the infrared camera and the ultraviolet camera are connected with the upper computer; and the upper computer is provided with an image processing and analysis module for carrying out processing and analysis on infrared images and ultraviolet images shot by the infrared camera and the ultraviolet camera to obtain a fault result. Compared with the prior art, the system and method are high in detection accuracy, can realize detection without cutting off the power and can realize real-time imaging, high efficiency and simple operation, and provide a new approach for fault detection of the electric power field.

The invention relates to a preparation method for an electrondrawing group containing semi-cyanine temperature-sensitive molecular optical probe. The preparation method comprises the following steps of: 1) mixing iodate of a raw material indoline derivative and aromatic aldehyde by molar ratio of 1:1, and performing reflux in ethanol for 10-15 hours; 2) adding KBF4 and performing reflux for 2 hours for anion exchange; and 3) obtaining the semi-cyanine temperature-sensitive molecular optical probe through recrystallization of absolute ethyl alcohol. The preparation method provided by the invention has the advantages that the electrondrawing group containing semi-cyanine temperature-sensitive molecular optical probe material can quickly determine and monitor temperature of a fluid industrial production line by arranging ultraviolet absorption or fluorescence emission spectrum detection monitoring points; and through fluorescence labeling of living animals by the electrondrawing group containing semi-cyanine temperature-sensitive molecular optical probe, image detection for body temperature of the living animals can be realized through fluorescence imaging technology, so that the electrondrawing group containing semi-cyanine temperature-sensitive molecular optical probe can be applied to fields of biomedical diagnosis and the like.

The invention provides a Fourier transform imaging spectrometer adopting lateral shear interference scanning, which can better realize spectral imaging detection in a ground staring state or a stable tracking state. The Fourier transform imaging spectrometer mainly comprises a pyramidal Michelson lateral shear two-beam interferometer used for generating linear interference fringes on an imaging surface of a target scenery, a movable mirror scanning mechanism used for driving one movable mirror in the lateral shear two-beam interferometer to axially move for one-dimension scanning of an interference pattern on the imaging surface, a Fourier optical imaging objective lens used for focusing emergent light from the lateral shear two-beam interferometer to the imaging surface, a CCD (charge coupled device) area-array camera used for detecting a scenery target image interfering modulation, an image data processor used for recording and processing image data output by the CCD area-array camera, and a control system used for coordination control of operation of the movable mirror scanning mechanism, the CCD area-array camera and the image data processor. The invention further provides a method for spectral imaging by the spectrometer.

The invention discloses a blood drawing nursing device for pediatrics department, and relates to the technical field of blood drawing nursing for pediatrics department. The blood drawing nursing device for pediatrics department comprises a bottom plate and a top plate, wherein a blood drawing auxiliary mechanism is arranged on the left side of the upper part of the bottom plate; a blood drawing nursing mechanism is arranged on the right side of the upper part of the bottom plate; the blood drawing auxiliary mechanism comprises a vascular imaging instrument, a group of radar inspection modulesand devices to be inspected; projecting equipment is mounted in the middle part of the rear side of the lower end of a sliding block; each device to be inspected comprises an inserting and connectingplate; each radar inspection module can monitor the corresponding module to be inspected; a hand fixing device comprises a wrist fixing clamp and a finger pressing plate; a finger exposing hole is formed in the finger pressing plate; the blood drawing nursing mechanism comprises an ultraviolet sterilizing lamp at the right part of the lower end of the top plate; and a disposable pressing column isconnected to the lower part of a cannula in an inserting manner. The blood drawing nursing device for pediatrics department disclosed by the invention has the beneficial effects that the blood drawing auxiliary mechanism can accurately display blood vessels and blood drawing syringe needles, so that the blood drawing auxiliary mechanism can better assist medical personnel to perform intravenous blood drawing, and besides, after blood drawing, nursing is more convenient.

The invention belongs to the field of optical imaging, and provides an off-axis catadioptric medium-long wave infrared system based on a concentric double-spherical reflector aiming at the requirements of an infrared band on a large-view-field, low-distortion and high-imaging-quality optical system. The method is mainly applied to the fields of satellite-borne large-range medium-resolution meteorological observation and the like. The system sequentially comprises a first spherical reflector, a second spherical reflector, n groups of folding axis mirrors and n groups of imaging compensation lens groups in the light propagation direction; the system is an off-axis system; the n groups of imaging compensation lens groups are distributed at the light emitting part of the second spherical reflector in a fan shape; one group of diaphragms, one group of folding shaft lenses and one group of imaging compensation lens groups form an independent imaging channel; incident light is reflected by the first spherical reflector, the second spherical reflector and the folding axis mirror in sequence, passes through each diaphragm and then vertically enters the compensation lens group of the corresponding imaging channel. The optical system has the characteristics of high imaging quality, large imaging view field, full-view-field constant ground element resolution, capability of working in an infrared band and the like.

The invention discloses a centrifugal microfluidic detection device and a centrifugal microfluidic detection system. The centrifugal microfluidic detection device comprises a power supply module, a control module, a rotating module, a cracking module, a heating module, an imaging detection module, a visual color detection module and a chip tray; and the imaging detection module can perform imaging detection on a test strip cavity of the chip, and the visual color detection module can perform color detection and absorbance detection on a reaction cavity of the chip. According to the centrifugal microfluidic detection device, the imaging detection module is arranged, so that imaging detection can be realized; by means of the visual color detection module, color detection can be achieved, and absorbance detection can also be achieved. Therefore, the centrifugal microfluidic detection device can realize two optical detections at the same time, and compared with the prior art that only one optical detection can be realized, the universality is effectively improved; immunodetection and nucleic acid detection can be realized at the same time, and the detection performance is improved.

The invention discloses a steel surface coating detection method and system, the system comprises an eddy current array probe, a detection host and a computer device, the eddy current array probe is composed of an eddy current array coil sensor and an encoder, the detection host comprises a high-frequency signal excitation module, a signal conditioning module and a high-speed signal acquisition module, and the computer equipment is used for performing data processing, data storage and image display on data acquired by detection analysis software. The eddy current array detection system is adopted, appropriate detection parameters are selected through debugging, imaging detection of the metal sheet coating quality can be achieved, the eddy current array detection image is high in signal-to-noise ratio, the detection result can display two-dimensional and three-dimensional images at the same time, the coating quality can be represented more visually, accurately and effectively, and the detection accuracy is improved. The detection system can obviously distinguish the poor-quality area of the coating, and is helpful for quickly judging the position and size of the coating defect.

The invention discloses a dual-mode radiometer system for millimetre-submillimetre waves. The system comprises an interference synthetic aperture radiometer and a real aperture radiometer, wherein the interference synthetic aperture radiometer adopts an annular surface antenna array with a vacant center; the antenna array can carry out spin-scanning in the antenna array plane around a central axis; the real aperture radiometer adopts large-caliber reflector antennae; and the reflector antennae are nested in the central position of the annular antenna array and can realize 2-degree-of-freedom rotary scanning in the azimuth direction and the pitch direction. The system has the following advantages: the observed frequency band width of the system is expanded; the complexity of the whole system is reduced; and the whole spatial resolution and imaging efficiency of the system are improved.

The invention discloses a satellite-borne horizontal staring and vertical scanning hyperspectral limb detection method. The detection method comprises the following steps: step 1, determining a limb detection view field; step 2, setting working parameters of limb detection; step 3, determining a single limb scanning sequence based on the step 1 and the step 2; step 4, determining a whole rail limb scanning sequence based on the step 3; and step 5, completing in-orbit calibration of the limb scanning light path. According to the invention, staring is carried out in the horizontal direction, scanning is carried out in the vertical direction from the bottom of the atmosphere upwards in sequence by adopting the scanning mirror, the integral time, gain and acquisition times of the imaging spectrometer can be set according to the radiation intensity of a detected target at each limb scanning height, limb detection with a high signal-to-noise ratio is realized, and in-orbit calibration is carried out by adopting double transmission plates. And the on-orbit high-precision calibration is realized.

The invention provides a lipid carbon-carbon double bond isomer mass spectrum imaging method based on visible light catalysis, and application thereof, and belongs to the technical field of mass spectrum detection. A novel derivatization reagent is sprayed on the surface of a tissue slice, then a tissue in-situ derivatization reaction is carried out under the catalysis of visible light, and mass spectrum imaging analysis is further carried out on the derivatized tissue slice by adopting an MALDI mass spectrum imaging technology, so that in-situ visual characterization of a lipid C=C double-bond isomer in a biological tissue is realized, therefore, the method has good practical popularization and application values.

The invention discloses a multiband integrated sensor optical system, which comprises a front beam compressing system, a beam splitting flat plate 1 for transmitting medium wave infrared light and reflecting visible light and laser, a beam splitting flat plate 2 for transmitting visible light and reflecting laser, an infrared optical system, a laser ranging system and a visible light optical system, which are arranged in sequence from an object side to an image side in the optical axis direction. The infrared optical system, the laser ranging system and the visible light optical system share the front beam compressing system, and form an infrared channel, a laser ranging channel and a visible light channel respectively; and the three channels can rotate around the Z axis for 360 degrees torealize azimuth scanning and detection, and can rotate around the X axis for 360 degrees to realize pitch scanning and detection, so that panorama coverage is realized. The multiband integrated sensor optical system is compact in structure, good in optical axis uniformity, high in pointing accuracy and easy in installation and adjustment, covers three bands of visible light, infrared and laser, realizes medium wave infrared and visible light imaging, and effectively improves performance of photoelectric detection equipment.

The invention discloses a G-quadruplex structure wrapped by a DNA framework as well as a preparation method and application of the G-quadruplex structure. Six DNA sequences required for assembling a framework structure, a Cy3 sequence and a Cy5 sequence required for forming a G-quadruplex probe are uniformly mixed in a buffer solution at the final concentration of 0.6 mu M, a sample is put into aPCR instrument to be subjected to program annealing from 95 DEG C to 4 DEG C within 3.5 hours, a G-quadruplex nanostructure (G4F) wrapped by a DNA framework is obtained, and under the condition that atarget sequence (miR122a) is deleted, only green fluorescence from Cy3 occurs. And when the target sequence exists, the fluorescence resonance energy transfer process can be promoted, so that Cy5 fluorescence is enhanced while Cy3 fluorescence is weakened. The preparation method is simple and low in cost, the prepared G4F can specifically detect the objective target, is not interfered by externalenvironmental factors and has high stability, a DNA framework structure can effectively protect a G-quadruplex probe from being degraded by intracellular substances in cells, a target sequence can beefficiently recognized, and intracellular imaging detection is achieved.

The invention belongs to the technical field of nanoprobes, and discloses a composite nanoprobe and a method for ratio imaging detection of a living body. The composite nanoprobe includes near-infrared organic fluorescent dyes and near-infrared inorganic rare earth nanomaterials, wherein the near-infrared organic fluorescent dyes contain cyanine, rhodamine or BODIPY probe molecules, and the near-infrared inorganic rare earth nanomaterials contain core structure or core‑shell structure of rare earth fluorides. Under the excitation of near-infrared light, both organic fluorescent dyes and rare earth nanomaterials can emit near-infrared light without interfering with each other. When interacting with specific species, the emission peak position or intensity of organic fluorescent dyes will change, while the emission peaks of rare earth nanomaterials will not be affected, resulting in the ratio of the two near-infrared emission peaks changing with the addition of specific species. Regular changes occur, and the detection and imaging functions of specific species can be realized by using this ratio change as a detection signal.

The invention discloses a spectral domain OCT detecting system and method based on segmented spectrum optical path coding. A dichroscope is arranged in a traditional reference arm, so that a light source spectrum is divided into two portions which arrive at a transmission light path and a reflection light path respectively. Due to the fact that the positions of plane mirrors in the transmission light path and the reflection light path are different, and the two portions of the spectrums cover different optical paths in the reference arm and interfere with returning light of two different depth sections in a sample. After the two portions of spectrum interference signals enter a detection arm, the spectrum interference signals are detected by pixel points in different regions of a CCD in a spectrometer, spectrum parallel obtaining is achieved on the non-aliasing condition. On the condition that the detection arm and a sample arm of spectrum domain OTC are not changed, a simple light splitting structure is additionally arranged in the reference arm, arrangement of different zero-optical-path positions in a sample and parallel detection of double reference arm spectrum domain OCT signals are achieved, and imaging range of the spectrum domain OCT is broadened.

The invention discloses an ultrasonic guided wave imaging detector and a method thereof. A field programmable logic array in a guided wave signal acquisition system is used for controlling a guided wave signal execution circuit for generating a guided wave detection signal, the signal is collected and processed by the field programmable logic array and transmitted to an imaging system through a PCIE bus, after transmitted guided wave detection data is received by the imaging system through the PCIE bus, imaging processing is performed through an embedded multi-core processor, and the processedsignal is sent to a display panel through an LVDS display signal line for display. Through the embedded multi-core processor, power consumption of the whole machine is reduced, the PCIE bus is employed to simplify the circuit connection relationship for high-speed signal communication between two systems, and a graphics processor (GPU) integrated in the embedded multi-core application processor achieves good real-time imaging while maintaining low power consumption.

The invention discloses a dual-mode surface plasmon coupled emission (SPCE) fluorescence imaging detection device and a dual-mode surface plasmon coupled emission fluorescence imaging detection method, and relates to fluorescence imaging detection. The device comprises a sample system, an incident arm system and a detection arm system, wherein the sample system comprises double rotary tables, a sample holder, a prism and an optical quartz substrate; the double rotary tables comprise an upper rotary table, a lower rotary table and a central shaft; the incident arm system comprises a laser source, an attenuator, a polarizer, an microobjective, a pinhole, a planoconvex lens, a square iris diaphragm and a first optical guide rail; the detection arm system comprises a light filter, an imaging lens, a CCD (charge coupled device) receiver and a second optical guide rail. The size of the square iris diaphragm in the incident arm system is adjusted to obtain a rectangular incident light spot with a proper size; the detection of SPCE imaging in an RK (Kretschmann) mode is selected; the detection of SPCE imaging in a KR (Reverse Kretschmann) mode is selected. Therefore, the problem of difficulty for detection when a fluorescence signal is weak in the single RK mode can be effectively avoided.

The invention discloses an X-ray digital flat panel imaging detection device, which belongs to the field of X-ray imaging, and comprises a ray tube and a digital flat panel detector, and further comprises a plurality of brackets, the top ends of the brackets are jointly provided with a top plate, the lower side of the top plate is provided with a rotating frame, and the rotating frame is of an inverted U-shaped structure. A lifting motor, a rotating motor and limiting sliding seats are installed on the top wall of the rotating frame, the two limiting sliding seats are symmetrically installed on the top wall of the rotating frame, and a circular sliding rail is installed on the bottom wall of the top plate. Omnibearing imaging detection of the to-be-detected object at different heights and angles can be achieved, the operation process is mechanical, rapid, efficient and high in efficiency, the movable platform is used for placing and moving the to-be-detected object, the auxiliary supporting device is used for stably supporting the to-be-detected object, then the to-be-detected object is stably placed in the moving process, the possibility of toppling is avoided, and the operation process is safe and reliable.

The invention discloses a method for detecting trace amounts of Ca<2+>, Sr<2+> and Ba<2+> in active cancer cells through single-channel fluorescence imaging. By using classic calixarene [4] derivativeas a probe, and the trace amounts of Ca<2+>, Sr<2+> and Ba<2+> in the active cancer cells are respectively detected through the single-channel fluorescence imaging. According to the method disclosedby the invention, detection on multi-target ions can be realized; a coordination compound of a probe-Ca<2+>, a probe-Sr<2+> and a probe-Ba<2+> can be respectively formed by the probe disclosed by theinvention and Ca<2+>, Sr<2+> and Ba<2+> in the cells, and intense fluorescence with different wavelengths can be emitted, so that detection is conveniently carried out, the visibility is good, the sensitivity is good, the selectivity is good, and real-time on-line detection of the Ca<2+>, Sr<2+> and Ba<2+> in the cells can be realized.

The invention provides a Fourier transform imaging spectrometer adopting lateral shear interference scanning, which can better realize spectral imaging detection in a ground staring state or a stable tracking state. The Fourier transform imaging spectrometer mainly comprises a pyramidal Michelson lateral shear two-beam interferometer used for generating linear interference fringes on an imaging surface of a target scenery, a movable mirror scanning mechanism used for driving one movable mirror in the lateral shear two-beam interferometer to axially move for one-dimension scanning of an interference pattern on the imaging surface, a Fourier optical imaging objective lens used for focusing emergent light from the lateral shear two-beam interferometer to the imaging surface, a CCD (charge coupled device) area-array camera used for detecting a scenery target image interfering modulation, an image data processor used for recording and processing image data output by the CCD area-array camera, and a control system used for coordination control of operation of the movable mirror scanning mechanism, the CCD area-array camera and the image data processor. The invention further provides a method for spectral imaging by the spectrometer.

The invention relates to an all-time imaging detector with a multifunctional window and a preparation method thereof. The device includes a multifunctional window and a detection part, and the multifunctional window includes a microlens array, a window body and an optical filter array; the microlens The array is integrated on the upper surface of the window body, and the top surface of each microlens unit is a spherical cap structure, and the top view projection of the spherical cap is a square, and the squares of the spherical cap top view projections of adjacent microlens units are connected; the filter array It is plated on the lower surface of the window body; the filter array includes four kinds of filters, which are respectively three kinds of monochromatic visible light combined with an infrared band-pass filter and an infrared filter; the detection part It is composed of an array of pixel units, each pixel unit includes four sub-pixel units, and the four sub-pixel units are directly opposite to four kinds of filters; the invention also introduces the preparation method of the microlens array and the detection method of the detector . The device of the invention can realize all-day detection.

The invention provides a coaxial field-biasing type long-wave infrared system based on a spherical reflecting mirror. The coaxial field-biasing type long-wave infrared system comprises a spherical reflecting mirror and a plurality of imaging compensation lens groups with diaphragms, wherein the spherical reflecting mirror and the plurality of imaging compensation lens groups are arranged successively along the light propagation direction. Each imaging compensation lens group with a diaphragm forms one independent imaging channel. The system is a coaxial system; and main light of each channel deviates at a specific view field to avoid mutual shielding of the imaging compensation lens group and the incident light. The plurality of imaging compensation lens groups are distributed at a light emitting part of the concentric spherical reflecting mirror in a fan-shaped manner; and the imaging compensation lens groups and the incident light are not on a same plane. The imaging compensation lens groups include a plurality of short-focus compensation mirrors, a plurality of medium-focus compensation mirrors and a plurality of long-focus compensation mirrors. The plurality of imaging compensation lens groups employ different correction mirror groups with different focuses to correct aberration for different view fields, thereby ensuring a constant high resolution.