Image Pickup Device Dynamic Discharge Control
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Solution Overview
Problem
Conventional image pickup devices have a narrow dynamic range, making it difficult to reproduce both dark and bright areas in an image, leading to issues like over-exposure or under-exposure, especially when capturing scenes with significant brightness variations, such as a person against a bright sky.
Innovation Solution
A photographing apparatus and method that adjust the discharging time of charges in an image pickup device using a combination of electronic and mechanical shutters, allowing for exposure time adjustments based on the photographing state, by detecting brightness levels and using a scan controller to vary the pulse width of the discharging pulse to match the curtain travel curve, thereby optimizing exposure across different areas and lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed discharging time is used to completely discharge charges, then afterimage is prevented, but dynamic range is limited and cannot capture both dark and bright areas
Solution Approach 1:
The patent applies dynamics by making the discharging time variable rather than fixed. The discharging time is dynamically adjusted based on the brightness of different regions in the image, allowing the system to adapt to varying lighting conditions across the scene. This enables the image pickup device to capture both dark and bright areas effectively while preventing afterimages in each region according to its specific brightness requirements.
Solution Approach 2:
The patent implements local quality by applying different discharging times to different regions of the image pickup device based on their local brightness characteristics. Dark regions receive longer discharging times to accumulate sufficient charge, while bright regions receive shorter discharging times to prevent overexposure and afterimages. This region-specific approach optimizes the dynamic range across the entire image.
2Illumination intensity
If a longer exposure time is used to capture dark areas, then dark regions are properly exposed, but bright areas become over-exposed and saturated
Solution Approach 1:
The patent applies local quality by implementing region-specific exposure control based on brightness detection. The image pickup device divides the scene into dark and bright regions, and applies different discharging times to each region. Dark regions receive extended exposure through longer discharging times to ensure proper illumination, while bright regions use shorter discharging times to prevent over-exposure and saturation, thus eliminating the harmful effect of uniform exposure on heterogeneous scenes.
Solution Approach 2:
The patent segments the image pickup process into multiple regions with different exposure requirements. By detecting brightness levels across different areas, the system segments the scene into zones that require different discharging times, allowing independent optimization of exposure for each segment rather than applying a single global exposure setting.
3Reliability
If a shorter discharging time is used to avoid afterimage, then bright areas are captured, but dark areas remain under-exposed
Solution Approach 1:
The patent resolves this contradiction by applying local quality through region-adaptive discharging time control. Instead of using a uniform short discharging time that would under-expose dark areas, the system detects regional brightness and applies longer discharging times specifically to dark regions while maintaining short discharging times in bright regions. This ensures both afterimage prevention in bright areas and sufficient exposure in dark areas.
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
Enables photography with a wide dynamic range by ensuring proper exposure across varying brightness levels, preventing afterimages and improving image quality by intentionally adjusting the exposure time in dark areas to simulate longer exposure, thus capturing both bright and dark regions effectively.
Implementation Method 1
an image pickup device having a plurality of pixels arranged in a matrix form and that photographs a subject by being exposed to light
Implementation Method 2
a scan controller that controls an exposure start scanning of the image pickup device by discharging charges accumulated in the image pickup device
Data Source
AI summary
Photographing having a wide dynamic range is performed by adjusting a discharging time for discharging charges accumulated in an image pickup device. A photographing apparatus comprises an image pickup device having a plurality of pixels arranged in a matrix form and photographs a subject by exposing the image pickup device to light, and also includes: a detector that detects a photographing state of the subject; an operation controller that controls an operation of a curtain body traveling to block light to the image pickup device; and a scan controller that controls an exposure start scanning of the image pickup device by discharging charges accumulated in the image pickup device before the traveling of the curtain body, wherein the scan controller adjusts a discharging time for discharging the charges accumulated in the image pickup device according to the photographing state of the subject.