Image Sensor Scene Determination via Luminance Convergence Control
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Solution Overview
Problem
Conventional image sensing apparatuses with narrow dynamic range image sensors struggle to accurately determine scene conditions such as brightness, color, and motion, leading to improper exposure and loss of detail in bright and dark areas, resulting in unnatural images.
Innovation Solution
An image sensing apparatus with a control unit that adjusts exposure and aperture based on real-time luminance convergence to a target range, using an evaluation value of scene determination calculated from images sensed by the image sensor, ensuring appropriate scene determination even with narrow dynamic range sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional image sensors with narrow dynamic range are used to sense images, then the device complexity is reduced, but the measurement precision of scene conditions such as brightness and color deteriorates
Solution Approach 1:
The patent applies preliminary action by performing multiple sequential exposures with different exposure conditions before final scene determination. The image sensing unit captures a series of images with varying exposure times or aperture settings, and the control unit selects the most appropriate image for scene analysis. This preliminary multi-exposure action enables accurate brightness and color measurement even with narrow dynamic range sensors, as each exposure captures different luminance ranges.
Solution Approach 2:
The patent implements parameter changes by systematically varying exposure parameters (exposure time, aperture value, gain) across multiple images. The control unit changes these parameters between successive exposures to ensure that at least one image falls within the optimal luminance range for accurate scene determination. This parameter variation compensates for the narrow dynamic range limitation and improves measurement precision without requiring complex sensor hardware.
2Productivity
If exposure control is performed without accurate scene determination, then the productivity is improved by faster processing, but the manufacturing precision of image quality deteriorates due to improper exposure
Solution Approach 1:
The patent implements feedback by using the sensed images to evaluate scene conditions (brightness, color, contrast) and then adjusting the exposure parameters based on this evaluation. The control unit continuously monitors the luminance distribution in captured images and adjusts subsequent exposure settings to maintain optimal image quality. This feedback loop ensures that exposure is always adapted to the current scene, preserving highlight and shadow details while maintaining efficient processing through automated control.
Solution Approach 2:
The patent applies dynamics by making the exposure parameters adaptive rather than fixed. The system dynamically adjusts exposure time, aperture, and gain based on real-time scene evaluation. The control unit modifies these parameters in response to changing scene conditions, ensuring that each captured image has appropriate exposure for its specific luminance characteristics. This dynamic adaptation maintains high image quality across varying lighting conditions without requiring manual intervention.
3Adaptability or versatility
If the luminance range of sensed images greatly varies, then the adaptability to different lighting conditions is improved, but the reliability of scene determination deteriorates due to highlight and shadow detail loss
Solution Approach 1:
The patent applies segmentation by dividing the luminance range coverage across multiple images with different exposure settings. Instead of attempting to capture the entire luminance range in a single exposure, the system segments the task into multiple exposures: one for highlight details, one for mid-tones, and one for shadow details. The control unit then evaluates scene conditions using the most appropriate segmented image, ensuring reliable determination even when the overall luminance range is very large.
Solution Approach 2:
The patent implements a composite approach by combining multiple images with different exposure characteristics to form a composite basis for scene determination. The control unit synthesizes information from multiple exposures, selecting or combining data from images that each capture different portions of the luminance range. This composite method ensures that scene determination relies on images with preserved detail in all luminance regions, improving reliability while maintaining adaptability to various lighting conditions.
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
The solution enables accurate scene determination and improved image quality by ensuring proper exposure and aperture control, reducing highlight and shadow detail loss, and maintaining image naturalness across varying brightness conditions.
Implementation Method 1
an image sensor which is a CCD image sensor or a CMOS image sensor
Data Source
AI summary
Receiving an instruction from a user to start sensing a still image, an image sensing apparatus performs scene determination based on an evaluation value of scene determination from an image sensed immediately after the luminance of the image converges to a predetermined range of a target luminance. The image sensing apparatus can accurately determine a scene of the image even the image sensor with a narrow dynamic range.