CMOS Image Sensor Dynamic Readout for Moving Subject Tracking
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Solution Overview
Problem
Existing image capturing systems face increased system load and energy consumption due to the need to read out a larger number of pixels, particularly in systems with pupil division readout functions, which complicates signal delay adjustment and makes it difficult to track moving subjects for focus control.
Innovation Solution
An image capturing apparatus with a CMOS image sensor that switches between first and second readout methods based on the detected moving direction of the subject, performing divided readout in every predetermined number of rows or columns to reduce the number of pixels read out while maintaining focus detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels in an image sensor increases, then the image quality and resolution are improved, but the system load and energy consumption increase due to the need to read out a larger number of pixels within a predetermined period of time
Solution Approach 1:
The image sensor is divided into a focus detection region and an image capture region. The focus detection region uses pupil division readout to read out a pair of signals from each pixel corresponding to light beams that have passed through different pupil regions, while the image capture region uses normal readout. This segmentation allows the system to maintain high image quality while reducing the overall system load by limiting the complex pupil division readout to only the necessary focus detection area.
2Measurement precision
If the number of pixels in an image sensor increases, then the image quality and resolution are improved, but the energy consumption increases due to the need to read out a larger number of pixels within a predetermined period of time
Solution Approach 1:
The image sensor is divided into a focus detection region and an image capture region. The focus detection region uses pupil division readout to read out a pair of signals from each pixel corresponding to light beams that have passed through different pupil regions, while the image capture region uses normal readout. This segmentation allows the system to maintain high image quality while reducing the overall system load by limiting the complex pupil division readout to only the necessary focus detection area.
3Measurement precision
If pupil division readout function is implemented, then focus detection accuracy is improved, but the number of signals to be read out increases and the system load further increases
Solution Approach 1:
Pupil division readout is applied locally only to the focus detection region where high-precision focus detection is required, while the image capture region uses standard readout methods. This local application of pupil division readout maintains focus detection accuracy without unnecessarily increasing the system load across the entire sensor.
Solution Approach 2:
The image sensor is divided into a focus detection region and an image capture region. The focus detection region uses pupil division readout to read out a pair of signals from each pixel corresponding to light beams that have passed through different pupil regions, while the image capture region uses normal readout. This segmentation allows the system to maintain high image quality while reducing the overall system load by limiting the complex pupil division readout to only the necessary focus detection area.
4Measurement precision
If signals are independently read out from each photoelectric conversion portion for focus control, then focus detection accuracy is improved, but the period of time required for reading out signals cannot be sufficiently shortened
Solution Approach 1:
The readout method is dynamically adjusted based on the readout region. In the focus detection region, pupil division readout is performed to obtain a pair of signals from each pixel for accurate focus detection. In the image capture region, normal readout is performed to maintain high-speed operation. This dynamic switching of readout methods allows the system to achieve both accurate focus detection and fast readout speeds.
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 reduces system load and energy consumption without degrading focus detection accuracy, allowing for effective tracking of moving subjects during image capturing.
Implementation Method 1
an image sensor that has a plurality of photoelectric conversion portions corresponding to each of a plurality of microlenses arranged in two-dimensions, and outputs an image signal corresponding to a quantity of incident light
Data Source
AI summary
An image capturing apparatus comprising: an image sensor that has a plurality of photoelectric conversion portions corresponding to each of a plurality of microlenses arranged in two-dimensions, and outputs an image signal corresponding to a quantity of incident light; a detection unit configured to detect a moving direction of a subject; a determination unit configured to, in a case where the subject is moving in a main scanning direction, determine to perform divided readout in every predetermined number of rows, and to perform added readout in the rows except for the every predetermined number of rows; and a control unit configured to control the image sensor by switching between the divided readout and the added readout in units of rows based on the determination result.