34results about How to "Improve autofocus accuracy" patented technology

A refined autofocus method provides optimized lighting between iterative autofocus operations, to reliably provide the best possible autofocus Z-height precision. The method includes a quantitative initial focus Z-height determination based on initial focus curve data from initial autofocus images acquired using initial light control parameters. Then, the camera is set at that initial focus Z-height such that well focused images are provided. Refined (optimized) light control parameters are then determined based on at least one respective image acquired using respective light control parameters at that Z-height, such that an image acquired using the refined light control parameters provides a near-optimum value for a contrast-related metric (e.g., a focus metric) at that Z-height. Then, refined autofocus images are acquired using the refined light control parameters and a refined precise Z-height is quantitatively determined base on the resulting focus curve.

A refined autofocus method provides optimized lighting between iterative autofocus operations, to reliably provide the best possible autofocus Z-height precision. The method includes a quantitative initial focus Z-height determination based on initial focus curve data from initial autofocus images acquired using initial light control parameters. Then, the camera is set at that initial focus Z-height such that well focused images are provided. Refined (optimized) light control parameters are then determined based on at least one respective image acquired using respective light control parameters at that Z-height, such that an image acquired using the refined light control parameters provides a near-optimum value for a contrast-related metric (e.g., a focus metric) at that Z-height. Then, refined autofocus images are acquired using the refined light control parameters and a refined precise Z-height is quantitatively determined base on the resulting focus curve.

A camera system includes an interchangeable lens and a camera body. A body controller in the camera body performs control to transmit a timing signal and a drive information signal to the interchangeable lens. A lens controller in the interchangeable lens controls drive of a focus lens based on the drive information signal and the timing signal which are received from the camera body. The drive information signal includes information of a driving time which is a period from a start of driving the focus lens until an end of driving the focus lens.

The invention discloses a self-focusing method for strip synthetic aperture radar images, and belongs to a self-focusing method for SAR images. The invention combines a phase gradient self-focusing PGA algorithm with a sub-aperture related MD algorithm to be applied to an algorithm PGA-MD in the self-focusing of strip synthetic aperture radar images. The method comprises the following steps: performing self-focusing processing on each sub-image by adopting the PGA algorithm to obtain high-precision sub-aperture phase error functions; calculating linear phase difference between sub-aperture phase error functions by utilizing the relationship between adjacent sub-images position phase offset and linear phase and applying the MD algorithm for realizing phase splicing; and finishing self-focusing processing for the strip SAR images. The invention substitutes the MD algorithm for traditional process of carrying out sub-aperture phase error function splicing based on the second derivative and improves the self-focusing effect of the strip SAR images.

An image pickup apparatus includes an image pickup device that includes a plurality of focus detection pixels, a phase difference detection type of a first focus detector, a contrast detection type of a second focus detector, and a controller. The controller is configured to allow the second focus detector to continue the focus detection when the shift amount detected by the first focus detector is larger than a threshold even when the second focus detector detects the lens position corresponding to the peak of the contrast value, and to move the image pickup lens to a lens position that provides a peak of a contrast value detected by the second focus detector when the shift amount is the threshold or smaller.

The embodiment of the invention discloses a method for laser-assisted automatic focusing. The method comprises: a laser-assisted focusing function starting instruction is received to activate a laser-assisted focusing function; a camera shooting instruction is received to start laser-assisted focusing; according to the focusing position of the camera, laser pulse transmitter and receiver are rotated and a low-intensity laser pulse is sent to the focusing position of the camera by the laser pulse transmitter; the laser pulse receiver receives the reflected low-intensity laser pulse, and a distance between an intelligent terminal and the focusing position of the camera is calculated according to time between sending the low-intensity laser pulse and receiving the low-intensity laser pulse; and according to the distance between the intelligent terminal and the focusing position of the camera, an image distance of the camera is set and focusing is carried out. According to the technical scheme provided by the embodiment of the invention, the laser pulse transmitter and receiver can be rotated according a focusing position needed by a user and laser-assisted automatic focusing at different focusing positions is supported, so that the automatic focusing precision of the intelligent terminal is improved and thus the user experience is improved.

The invention discloses an automatic focusing unit and method. The automatic focusing unit comprises: a light source emitting a light beam, a light path adjuster which adjusts the emission direction of the light beam emitted by the light source entering the light path adjuster, an objective lens which makes the light beam adjusted by the light path adjuster emit to a detecting object, an optical sensor which senses an image formed by reflection of the light beam adjusted by the light path adjuster entering the detecting object, with the light path adjuster reducing the position change of the image sensed by the optical sensor, a signal processing unit that judges the off-focusing position of the detecting object according the image sensed by the optical sensor, and a drive unit which, controlled by the signal processing unit, changes the relative position between the objective lens and the detecting object to make the detecting object move to a focusing position of the objective lens.The automatic focusing unit can reduce the influence of the light source disturbance upon the automatic focusing precision.

A camera system includes an interchangeable lens and a camera body. A body controller in the camera body performs control to transmit a timing signal and a drive information signal to the interchangeable lens. A lens controller in the interchangeable lens controls drive of a focus lens based on the drive information signal and the timing signal which are received from the camera body. The drive information signal includes information of a driving time which is a period from a start of driving the focus lens until an end of driving the focus lens.

In a camera system including an interchangeable lens and a camera body, a body controller performs control a drive signal transmission unit to drive a focus lens in a predetermined direction, and transmit a timing signal to the interchangeable lens. The lens controller performs control to detect a position of the focus lens in synchronization with the timing signal received from the camera body and store the detected position in a storage unit.

In a camera system according to the present invention, a lens controller obtains an exposure synchronizing signal that is generated by a camera controller from a camera body, causes a configuration formed of a first encoder, a second encoder and a counter to detect the position of a focus lens according to the obtained exposure synchronizing signal, and notifies the camera body of the detected position of the focus lens. The camera controller associates the position of the focus lens or the mechanism member obtained from the lens controller with an AF evaluation value based on the exposure synchronizing signal, and controls an autofocus operation of the camera system based on the position and AF evaluation value that are associated with each other. With this configuration, it is possible to improve the accuracy of an autofocus operation with a contrast system.

A focal point detector includes: a condenser lens for transmitting a light image from an optical system; and a distance measurement sensor group for receiving a luminous flux which has passed through the condenser lens. The sensor group includes a first distance measurement sensor pair for receiving divided beams of the luminous flux for a first focus detection region which is located off the center of a shooting region. The first distance measurement sensor pair includes first and second distance measurement sensors. The first focus detection region extends in a first direction in the shooting region from a position where the first focus detection region is spaced from the center in the first direction and also in a second direction. The first and second distance measurement sensors are spaced from each other and arranged at different angles in the direction associated with the first direction on the sensor arrangement surface.

An image pickup apparatus includes an image pickup device that includes a plurality of focus detection pixels, a phase difference detection type of a first focus detector, a contrast detection type of a second focus detector, and a controller. The controller is configured to allow the second focus detector to continue the focus detection when the shift amount detected by the first focus detector is larger than a threshold even when the second focus detector detects the lens position corresponding to the peak of the contrast value, and to move the image pickup lens to a lens position that provides a peak of a contrast value detected by the second focus detector when the shift amount is the threshold or smaller.

An auto-focus (AF) method adapted for an image capturing device includes following steps. When a first press signal generated by a user pressing a button of the image capturing device is detected, a local peak searching method is applied to perform an AF procedure. It is determined whether a second press signal generated by the user pressing the button is detected. If not, it is determined whether a first released signal generated by the user releasing the button is detected. The continuous pressing count is calculated according to the first released signal and the first press signal that are continuously generated. Whether the continuous pressing count is greater than a first threshold is determined. If yes, a global peak searching method is applied to perform the AF procedure. If not, the local peak searching method is still applied to perform the AF procedure.

The invention belongs to the field of radar signal processing, and specifically relates to a SA-ISAR self-focusing method based on joint constraints of structure sparsity and entropy, comprising the following steps: S1: performing echo modeling on radar echoes after envelope alignment; S2: Apply a hierarchical structured sparse prior to the ISAR image; S3: update the ISAR image and high-level variables through a relaxed variational Bayesian method; S4: update the phase error through a fixed point-based minimum entropy method; S5: Judging whether the termination condition is reached, if the termination condition is reached, the iterative cycle is stopped, otherwise, return to S3, and the self-focused image is output until the termination condition is reached. The present invention can improve the self-focusing precision of the ISAR image under the sparse aperture, so that the formed ISAR image is clearer; the present invention has low computational complexity, fast iterative convergence speed, and strong ability to resist the sparse aperture.

The driving module controls the supply of current to a shape memory alloy member by setting a command value for an electrical resistance of the shape memory alloy member so that the lens frame is moved intermittently to thereby controlling the driving of driving means. The driving module includes control means which includes resistance detection means, command value generation means, and current supplying means. The command value generation means changes the command value gradually by a predetermined variation width R so that the electrical resistance of the shape memory alloy member increases or decreases gradually by a predetermined width when the lens frame is moved intermittently. Moreover, the command value generation means performs a correction calculation which uses the ratio of an actual reference value R 0 of the electrical resistance of the shape memory alloy member to an ideal reference value R stan of the electrical resistance of the shape memory alloy member as a correction ratio to calculate a correction variation width by multiplying the correction ratio by an ideal variation width R step of the command value R t ( n ) to thereby change the command value R t ( n ) gradually using the correction variation width as the variation width R.

The invention discloses an automatic focusing unit and method. The automatic focusing unit comprises: a light source emitting a light beam, a light path adjuster which adjusts the emission direction of the light beam emitted by the light source entering the light path adjuster, an objective lens which makes the light beam adjusted by the light path adjuster emit to a detecting object, an optical sensor which senses an image formed by reflection of the light beam adjusted by the light path adjuster entering the detecting object, with the light path adjuster reducing the position change of the image sensed by the optical sensor, a signal processing unit that judges the off-focusing position of the detecting object according the image sensed by the optical sensor, and a drive unit which, controlled by the signal processing unit, changes the relative position between the objective lens and the detecting object to make the detecting object move to a focusing position of the objective lens. The automatic focusing unit can reduce the influence of the light source disturbance upon the automatic focusing precision.

An auto-focus (AF) method adapted for an image capturing device includes following steps. When a first press signal generated by a user pressing a button of the image capturing device is detected, a local peak searching method is applied to perform an AF procedure. It is determined whether a second press signal generated by the user pressing the button is detected. If not, it is determined whether a first released signal generated by the user releasing the button is detected. The continuous pressing count is calculated according to the first released signal and the first press signal that are continuously generated. Whether the continuous pressing count is greater than a first threshold is determined. If yes, a global peak searching method is applied to perform the AF procedure. If not, the local peak searching method is still applied to perform the AF procedure.

The embodiment of the present invention discloses a method for laser-assisted auto-focusing. The method includes: receiving an instruction to activate the laser-assisted focusing function to activate the laser-assisted focusing function; receiving a camera shooting instruction to start the laser-assisted focusing; Rotating the laser pulse transceiver, sending low-intensity laser pulses to the focus position of the camera through the laser pulse transmitter; receiving the reflected low-intensity laser pulses through the laser pulse receiver, according to sending and receiving the low-intensity laser pulses Calculate the distance between the smart terminal and the focus position of the camera; set the image distance of the camera and focus according to the distance from the smart terminal to the focus position of the camera. The technical solutions of the embodiments of the present invention can rotate the laser pulse transceiver according to the focus position required by the user, support laser-assisted auto-focus at different focus positions, improve the auto-focus accuracy of the smart terminal, and thereby improve user experience.

The invention relates to a self-focusing preprocessing method based on a short-time fractional order Fourier domain filter, which belongs to the field of synthetic aperture radar (SAR) signal processing. The method comprises the following steps of: (1) extracting a phase error signal of a single special showing point; (2) judging whether the phases of the phase error signal mainly are quadratic phase or not; (3) filtering noise in a transform domain: if the phases mainly are quadratic phases, using short-time fractional order Fourier domain filter; otherwise, using short-time Fourier domain filter; and (4) inversely transforming result time frequency to a time domain, estimating and compensating the phase error and realizing self-focusing preprocessing. The method effectively solves the problems of estimation and compensation of the phase error in a low-signal-to-noise ratio environment, especially the estimation and compensation of the quadratic phase error, and can obtain the main part of a phase error course and greatly improve the imaging quality after removing the phase error course from an original signal, thereby improving the signal-to-noise ratio of a special showing point signal.