Dual Readout Image Pickup Apparatus for Dynamic Focus Control
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in improving operability and reducing power consumption while maintaining high-speed focus control and preventing degradation of live view image quality, as they often require temporary stopping of image pickup and simultaneous reading at multiple frame rates, leading to increased power consumption and time lag.
Innovation Solution
The apparatus employs a dual readout system where one unit acquires image data for display at a lower frame rate and another unit acquires data at a higher frame rate for focus control, starting and terminating based on object state changes and user operations, allowing for simultaneous output and reducing unnecessary image pickup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If images are simultaneously read out at multiple frame rates, then focus control speed is improved, but power consumption increases
Solution Approach 1:
The patent dynamically switches between single-frame-rate and dual-frame-rate reading modes based on whether focus control is needed. During EVF display without focus control, only single-frame-rate reading occurs. When focus control is required, dual-frame-rate reading is activated temporarily, then returns to single-frame-rate mode after focus control completes, optimizing power consumption while maintaining focus control capability.
Solution Approach 2:
The patent implements periodic focus control operations where the image pickup device alternates between normal EVF display mode and focus control mode. During focus control, high-frame-rate reading is performed periodically to acquire focus information, then returns to standard EVF display frame rate, creating a rhythmic pattern of high and low power consumption states.
2Speed
If frame rate is changed for focus control, then focus determination speed is improved, but operability deteriorates due to waiting time
Solution Approach 1:
The patent performs focus control operations in advance during EVF display before the user presses the shutter button. By completing focus determination beforehand, the system eliminates waiting time during the actual shooting moment, improving operability while maintaining high focus determination speed through preliminary high-frame-rate reading.
3Use of energy by moving object
If image pickup is temporarily stopped, then power consumption is reduced, but operability deteriorates due to time lag
Solution Approach 1:
Instead of temporarily stopping image pickup, the patent dynamically controls the reading frame rate. The image pickup device continues operating at normal EVF display frame rate, and only activates additional high-frame-rate reading when focus control is needed, then deactivates it afterward. This dynamic approach maintains continuous image capture capability while reducing power consumption, avoiding the time lag and operability issues caused by temporary stops.
Data Source
AI summary
An image pickup apparatus that makes it unnecessary to temporarily stop image pickup performed by an image pickup device to thereby improve operability of the image pickup apparatus, and achieves power saving. In an image pickup apparatus having an electronic viewfinder function, first image signals for live view are acquired by thinning read lines of an image pickup device, and second image signals for AF evaluation value calculation are acquired from the other read lines at a higher speed than the first image signals, for simultaneous output with the first image signals. Reading of the second image signals is started when the state of the object of image data changed or when one photographing mode is changed to another by a user's operation, and is terminated when a reading termination condition set in advance in association with the reading start condition is satisfied.