50 results about "Focal shift" patented technology

A large depth of focus (DOF) display provides an image in which the apparent focus plane is adjusted to track an accommodation (focus) of a viewer's eye(s) to more effectively convey depth in the image. A device is employed to repeatedly determine accommodation as a viewer's gaze within the image changes. In response, an image that includes an apparent focus plane corresponding to the level of accommodation of the viewer is provided on the large DOF display. Objects that are not at the apparent focus plane are made to appear blurred. The images can be rendered in real-time, or can be pre-rendered and stored in an array. The dimensions of the array can each correspond to a different variable. The images can alternatively be provided by a computer controlled, adjustable focus video camera in real-time.

Provided are a lens unit and a vehicle-mounted infrared lens unit capable of correcting a focal shift due to a temperature change without increasing the apparatus size, complicating a production process, and increasing the costs. In a vehicle-mounted infrared lens unit 4 configured such that a plurality of infrared lenses are held by a barrel 30 and a spacer 40 is interposed between two infrared lenses, a first infrared lens 10 is held sandwiched between the spacer 40 and a lens holding portion 31 of the barrel 30. The spacer 40 and the barrel 30 are formed of materials having different thermal expansion coefficients. An O-ring 60 is interposed between a lock portion 32 of the lens holding portion 31 and the first infrared lens 10. Thermal expansion of the spacer 40 allows the first infrared lens 10 to move in the axial direction against the elastic force of the O-ring 60. When the spacer 40 is shrunken, the elastic force of the O-ring 60 allows the first infrared lens 10 to move in the opposite direction.

Focusing systems for which variation of magnification with focus is either inherently compensated, or is calibrated and corrected. The required conditions for inherent compensation are determined, and the desired state is called constant relative magnification. It is shown that telecentricity does not guarantee constant relative magnification. Both telecentric and non-telecentric accessory cameras for endoscopes are disclosed that have constant relative magnification, as are additional optical systems for general metrological purposes. Methods for calibrating change in relative magnification and deviation of the optical axis with focal shift are disclosed, as are methods for incorporating these changes into perspective dimensional measurements. Embodiments are disclosed in which only a single quantity need be measured to perform the correction, and these embodiments require only a low-resolution position transducer to provide accurate measurements. Apparatus is disclosed that enables an accessory camera to be aligned to an endoscope using only externally accessible adjustments. This apparatus also makes it possible to de-mount the camera from one endoscope and re-mount it to another without requiring any recalibration.

Focusing systems for which variation of magnification with focus is either inherently compensated, or is calibrated and corrected. The required conditions for inherent compensation are determined, and the desired state is called constant relative magnification. It is shown that telecentricity does not guarantee constant relative magnification. Both telecentric and non-telecentric accessory cameras for endoscopes are disclosed that have constant relative magnification, as are additional optical systems for general metrological purposes. Methods for calibrating change in relative magnification and deviation of the optical axis with focal shift are disclosed, as are methods for incorporating these changes into perspective dimensional measurements. Embodiments are disclosed in which only a single quantity need be measured to perform the correction, and these embodiments require only a low-resolution position transducer to provide accurate measurements. Apparatus is disclosed that enables an accessory camera to be aligned to an endoscope using only externally accessible adjustments. This apparatus also makes it possible to de-mount the camera from one endoscope and re-mount it to another without requiring any recalibration.

There is provided an optical system and method for shaping a polychromatic light into a substantially uniform profile beam along a first axis. A polychromatic divergent light with having multiple wavelength components is provided with a dispersion of divergence. A collimation optic collimates the polychromatic divergent light. A shaping lens shapes the collimated beam into a shaped beam with a nearly uniform profile along the first axis, the dispersion of divergence causing a deviation from uniformity of the nearly uniform profile. A focusing optic focuses the shaped beam. A combination of the collimation and focusing optics shows a chromatic focal shift that compensates for said dispersion of divergence, so as to reduce the deviation from uniformity to obtain a profile with a substantially uniform intensity along the first axis, for all of said multiple wavelength components.

An imaging element includes pixel portions each having a first sub-pixel and a second sub-pixel and outputs a phase difference detection-type focus detecting signal. An image signal A includes information for the first sub-pixel and an image signal AB includes information for the second sub-pixel. A level determining unit compares the image signal A with a threshold value SHA and compares the image signal AB with a threshold value SHAB. A correlation calculation processing unit performs correlation calculation for a signal excluding the image signal A having a level exceeding the threshold value SHA and the image signal AB having a level exceeding the threshold value SHAB so as to output the result of calculation to a CPU. The CPU calculates a focal shift amount in accordance with the result of calculation and performs a focus adjusting operation by drive-controlling a focus lens.

Transparent heat-conductive layers of significant thickness are bonded or adhered to opposing optical faces of a Faraday optic to form a Faraday optic structure that can be used with beam-folding mirrors and an external magnetic field to form a multi-pass Faraday rotator with minimal thermal gradient across the beam within the Faraday optic. The transparent heat conductive layers conduct heat through the Faraday optic substantially parallel to the beam propagation axis for each pass through the Faraday optic structure and thereby reduce thermal gradients across the beam cross section that would otherwise contribute to thermal lens focal shifts and thermal birefringence in the Faraday optic structure. The multi-pass Faraday rotator of this invention is suitable for use with any device based upon the Faraday effect such as optical isolators, optical circulators and Faraday mirrors that are scalable with beam size to power levels in excess of 2 kW.

In order to eliminate and suppress image quality degradation including the occurrence of an artifact and the deterioration of quantitative performance caused by a focal shift, without delaying a photographing timing by accurately estimating the shift amount of a focal position without x-ray irradiation for detecting the focal position and by changing the x-ray irradiation field, disclosed is an X-ray CT device provided with: an X-ray generation means (100); an X-ray detection means (104); an X-ray collimator means (303); a reconstruction processing means (105); an irradiation field change drive means (200, 301, 302) which controls and moves at least one of the X-ray generation means (100), the X-ray detection means, and the X-ray collimator means (303); and a shift amount calculation means (105) which estimates the focal position of the X-ray generation means at an estimation time (S2, S4), and using the result of the estimation, calculates the shift amount, which is needed to keep the X-ray incident position in the X-ray detection means constant, of the irradiation field change drive means (S6). When a predetermined time has passed since a time at which the focal position is estimated in the most recent past, or when a photographing start instruction signal is inputted, the shift amount calculation means calculates the shift amount (S8), and the irradiation field change drive means performs the control and shift corresponding to the shift amount before the next estimation time or X-ray irradiation (S9).

To stably carry out recording and reproducing to and from a high density optical disk without using a double servo in the optical disk using a high NA objective lens.

A detection of a spherical aberration and a detection of a coma aberration in a radial direction are simultaneously performed, and the coma aberration generated with the offset of an objective lens 109 is corrected in real time, thus enlarging an allowable offset amount of the objective lens. In order to simultaneously detect the spherical aberration and the coma aberration, focal shift and tracking shift signals in an inside region and outside region of reflected light flux are detected respectively, and the differential signals are set as spherical aberration and coma aberration signals.

An integrated image sensor and lens assembly may include a lens barrel, a collet, and a lens mount. The lens barrel may be coupled to the collet which is coupled to the lens mount. The lens barrel and the collet may each include a fastening structure reciprocal to each other. Alternatively, the collet and the lens mount may each include a fastening structure reciprocal to each other. The optical distance between the set of lenses and the image sensor may be tuned such that the focal plane of the lenses coincides with the image plane. The fastening structures allow the lens barrel to be adjusted relative to the lens mount in order to shift the focal plane in a direction along the optical axis to compensate for focal shifts occurring during assembly/cure and/or temperature cycling.

A super resolution pupil filter with focus movement controlled by electricity belongs to the optical super resolution technical field, which comprises a polarizer (1), an Lambada/4 delay wave plate (2) of Lambada Pi/4 azimuth angle, an electro-optic crystal (3), a radial symmetry doubly refracting crystal (4), an Lambada/4 delay wave plate (5) of 3 Pi/4 azimuth angles, and an analyzer (6). The polarizer (1) is parallel to a euphotic shaft of the analyzer (6), and the azimuth angle of the electro-optic crystal (3) is defined according to the position of an electric induction main shaft, and an electric induction slow shaft is consistent with an euphotic shaft of the polarizer (1). The slow shaft direction of the radial symmetry doubly refracting crystal (4) has an included angle of Pi/4 with the euphotic shaft of the polarizer (1). The size of an electric field size added outside of the electro-optic crystal (3) is defined according to a half wave voltage of the electro-optic crystal, and the voltage change range is between the half wave voltage of o to 2 times. The invention can synchronously realize the electric control of transverse super resolution and radial focus moving effect by conducting electro-optic modulation to the electro-optic crystal.

A broadband ellipsometer is disclosed with an all-refractive optical system for focusing a probe beam on a sample. The ellipsometer includes a broadband light source emitting wavelengths in the UV and visible regions of the spectrum. The change in polarization state of the light reflected from the sample is arranged to evaluate characteristics of a sample. The probe beam is focused onto the sample using a composite lens system formed from materials transmissive in the UV and visible wavelengths and arranged to minimize chromatic aberrations. The spot size on the sample can be less than 3 mm and the aberration is such that the focal shift over the range of wavelengths is less than five percent of the mean focal length of the system.

The invention discloses an infrared induction switching zoom lens and an imaging monitoring method thereof. The lens includes a mechanically connected infrared filter, a switching device, and a focusing lens group; in the visible light mode, the infrared filter is moved into the optical system of the lens through the switching device , used to block infrared light; in the infrared light mode, the infrared filter moves out of the optical system of the lens through the switching device; the focusing lens group is associated with the infrared filter, and is used to correct the optical system for focus shift. Due to the use of the focusing lens group to switch the optical system where the focal point shifts, only one infrared filter can be used to switch between the visible light mode and the infrared light mode, thereby avoiding the problem caused by the characteristics of crystal and other materials. The infrared transmittance of the optical system in night vision is only 90%, which improves the infrared light transmittance of the optical system at night; increases the brightness of the imaging monitoring screen, reduces image noise, and makes the screen clearer and cleaner.

A scanning optical device wherein, on the basis of positional information concerning a spacing in a main-scan direction between imaging positions of a plurality of light beams passed through resin-made imaging optical elements and detected by a photodetecting device and a spacing between the imaging positions in a sub-scan direction of the plurality of light beams, a focal shift direction and a focal shift amount in the main-scan direction as well as a focal shift direction and a focal shift amount in the sub-scan direction are determined, and wherein an optical element of an input optical system is moved in an optical axis direction based on the determination, to correct the focal shift in the main-scan direction and the focal shift in the sub-scan direction.

A method for judging the center of focus and process control of a lithography tool. Diffractive features are obtained from multiple diffractive structures located within multiple different focus setting fields. The variability of the diffraction characteristics of each field is determined by direct analysis or comparison with a database. The variability or uniformity can be represented by any measurement, including the standard deviation or range of values ​​of selected features of a database of theoretical diffraction structures or the variability or uniformity of the diffractive features themselves, as represented by RMS differences or intensity ranges. These methods can be used to process control and monitor focus shift by determining the internal field variation of the diffractive features of multi-diffractive structures in a series of wafers.