Imaging Apparatus Pixel Exposure Control for Live-View Frame Rate
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Solution Overview
Problem
Existing imaging apparatuses face challenges in synchronizing the exposure and reading of pixel signals from imaging pixels and focus detection pixels within the time frame of a display frame rate, affecting the accuracy of live-view display and focus detection.
Innovation Solution
The imaging apparatus alternates or synchronizes the exposure and reading of pixel signals from imaging and focus detection pixels based on the display frame rate, either by alternating them within the frame rate or performing simultaneous exposure followed by reading, to maintain display frame rate and ensure accurate focus detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pixel signals from imaging pixels and focus detection pixels are read alternately within display frame rate time, then live-view display and focus detection can be performed, but it becomes difficult to complete both exposure and reading operations within the time frame
Solution Approach 1:
The image pickup device is segmented into two distinct types of pixels: imaging pixels for live-view display and focus detection pixels for phase difference autofocus. This segmentation allows independent optimization of exposure and reading operations for each pixel type, enabling the system to complete both operations within the display frame rate time frame by processing imaging pixels and focus detection pixels in separate alternating cycles.
Solution Approach 2:
The control unit implements periodic action by alternately performing exposure and reading operations between imaging pixels and focus detection pixels within each display frame rate cycle. This periodic switching ensures that both pixel types receive adequate exposure time while their signals are read sequentially, maintaining the required display frame rate without compromising focus detection accuracy.
2Loss of time
If exposure and reading of imaging pixels and focus detection pixels are performed simultaneously, then time efficiency is improved, but synchronization within display frame rate becomes difficult to achieve
Solution Approach 1:
The reading operation is segmented into separate processing streams for imaging pixels and focus detection pixels. The control unit reads pixel signals from one type of pixel at a time in alternating fashion, ensuring that each pixel type completes its exposure and reading cycle fully before switching to the other type, thereby maintaining synchronization within the display frame rate.
Solution Approach 2:
The control unit performs preliminary action by pre-planning and coordinating the exposure timing and reading sequence for both imaging pixels and focus detection pixels before each display frame rate cycle begins. This advance coordination ensures that the alternating exposure and reading operations are synchronized to complete within the required time frame.
3Measurement precision
If focus detection pixels are used for phase difference autofocus, then focus detection accuracy is improved, but the complexity of coordinating exposure and reading operations increases
Solution Approach 1:
The image pickup device segments pixels into imaging pixels and focus detection pixels with different opening positions, allowing dedicated phase difference autofocus functionality. The control unit manages this segmentation by implementing a simplified alternating reading scheme that reduces coordination complexity compared to simultaneous multi-pixel-type processing.
Solution Approach 2:
The control unit applies periodic action by establishing a regular alternating pattern for exposure and reading operations between imaging pixels and focus detection pixels. This periodic rhythm simplifies the coordination complexity by providing a predictable, repeating sequence that is easier to manage than arbitrary or simultaneous processing of multiple pixel types.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach maintains the display frame rate and ensures accurate phase difference focus detection, improving the overall performance of live-view display and focus detection in imaging systems.
Implementation Method 1
forms subject light fluxes which have passed through different pupil areas that are symmetrical with respect to an optical axis center of an imaging lens into an image on focus detection pixels, and detects a phase difference between the subject light fluxes, thereby detecting a focal state of the imaging lens
Data Source
AI summary
An imaging apparatus includes a reading unit, a display unit, and a control unit. The reading unit reads pixel signals from imaging pixels and focus detection pixels. The display unit displays an image. When both exposure/reading of the imaging pixels and the focus detection pixels are achievable within time corresponding to a display frame rate of the display unit, the control unit controls to alternate the exposure/reading of the imaging pixels and the exposure/reading of the focus detection pixels. When both the exposure/reading of imaging pixels and the focus detection pixels are not achievable within the time, the control unit controls to perform the exposure of the imaging pixels and the focus detection pixels at the same time and read the pixel signals of the imaging pixels and the focus detection pixels after the end of the exposure of the imaging pixels and the focus detection pixels.