35results 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 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.

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.

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.