Imaging Apparatus Exposure Control via Histogram Analysis
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Solution Overview
Problem
Existing imaging devices face challenges in independently controlling exposure times for imaging and detection pixels, which affects focus detection efficiency and image quality.
Innovation Solution
The apparatus includes first and second light receiving units that convert light beams into voltage pulses using the avalanche effect, with a controller generating image data and detecting focus states, and an exposure time control unit that adjusts exposure times based on histogram analysis to optimize detection pixel performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If exposure time for detection pixels is extended to improve focus detection accuracy, then measurement precision improves, but saturation occurs reducing reliability
Solution Approach 1:
The pixel array is segmented into imaging pixels and detection pixels, allowing independent control of exposure times for each type. Detection pixels can have their exposure time independently adjusted and controlled separately from imaging pixels, enabling optimization of exposure time for focus detection without affecting image capture parameters.
Solution Approach 2:
The exposure time for detection pixels is made dynamically adjustable based on imaging conditions. The control unit determines appropriate exposure times for detection pixels according to the imaging state, allowing the system to adapt exposure parameters in real-time to prevent saturation while maintaining detection accuracy.
2Reliability
If exposure time for detection pixels is reduced to prevent saturation, then reliability improves, but focus detection accuracy deteriorates
Solution Approach 1:
The control unit uses feedback from the imaging state to determine appropriate exposure times for detection pixels. By monitoring imaging conditions and adjusting detection pixel exposure times accordingly, the system maintains optimal exposure levels that prevent saturation while ensuring sufficient signal for accurate focus detection.
3Adaptability or versatility
If independent control of imaging and detection pixels is implemented, then adaptability improves, but device complexity increases
Solution Approach 1:
The control unit is designed to perform multiple functions: controlling both imaging pixels and detection pixels, determining exposure times based on imaging states, and managing readout operations. This multi-functional approach provides independent control capability while avoiding the need for completely separate control systems for each pixel type.
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 solution enables efficient focus detection and improved image quality by independently controlling exposure times for detection pixels, reducing saturation and underexposure issues, and enhancing the overall imaging process.
Implementation Method 1
the first light receiving units each converting a light beam entering from an exit pupil of an imaging optical system into a first voltage pulse based on an avalanche effect
Implementation Method 2
the second light receiving units each converting a light beam entering from a part of the exit pupil of the imaging optical system into a second voltage pulse based on the avalanche effect
Data Source
AI summary
An apparatus includes an imaging device including a plurality of light receiving units each converting a light beam into a voltage pulse based on an avalanche effect, and a controller having a processor which executes instructions stored in a memory, the controller being configured to function as a generation unit configured to generate image data based on the voltage pulse, a detection unit configured to detect a focus state of an imaging optical system based on the voltage pulse, and a control unit configured to control an exposure time of the light receiving units. The control unit includes a histogram generation unit and a determination unit. The histogram generation unit generates a histogram of the plurality of light receiving units based on the voltage pulse, and the determination unit determines an exposure state of the plurality of light receiving units based on the histogram generated by the histogram generation unit.