Image Pickup Apparatus Flicker Detection via Rolling Shutter Area Division
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in accurately detecting flicker under varying luminance conditions, leading to uneven exposure and reduced flicker detection accuracy when using high-speed shutters with flicker light sources.
Innovation Solution
The apparatus employs a rolling shutter method, dividing image data into predetermined areas and performing flicker detection using a lower frame rate, allowing for accurate flicker waveform recognition and synchronization with flicker peak timing, even at low luminance levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sampling is performed at a frequency several times or more the flicker cycle to improve flicker detection accuracy, then flicker detection accuracy is improved, but charge accumulation time must be secured which reduces frame rate and reduces the number of samplings
Solution Approach 1:
The image pickup device is divided into a plurality of regions, and image data from each region is separately accumulated and processed. This segmentation allows the system to accumulate sufficient charge in each region even at lower frame rates, maintaining flicker detection accuracy while enabling high-speed shooting.
2Illumination intensity
If frame rate is reduced to secure charge accumulation time for sufficient brightness, then charge accumulation time is secured, but the number of samplings is reduced which decreases flicker detection accuracy
Solution Approach 1:
Image data from multiple regions is merged/combined to accumulate sufficient charge for bright image data. By combining signals from multiple regions, the system achieves adequate brightness and signal-to-noise ratio for accurate flicker detection even when individual regions have limited charge accumulation time due to high frame rates.
3Speed
If high-speed shutter is used under flicker light source to improve shooting speed, then shooting speed is improved, but brightness of light source changes during shutter movement causing uneven exposure
Solution Approach 1:
The system detects flicker characteristics by analyzing luminance changes across multiple frames and regions, then uses this feedback information to determine optimal shooting timing. By identifying the peak timing of the flicker light source through detection feedback, the system can synchronize exposure to achieve uniform exposure even with high-speed shutters.
Data Source
AI summary
An image pickup apparatus includes an image pickup device that picks up a subject by driving by a rolling shutter method, a memory that stores a set of instructions and at least one processor that executes the instructions to divide, when driving the image pickup device at a second frame rate lower than a first frame rate, a plurality pieces of image data successively acquired by the image pickup device at the second frame rate into predetermined areas to acquire data of divided areas, and perform flicker detection using a predetermined number of pieces of the data of the divided areas successive for a plurality of frames.