Digital Camera Divided Exposure Image Processing
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Solution Overview
Problem
Conventional digital cameras face limitations in exposure control, particularly when capturing high brightness subjects, leading to issues like blown-out highlights due to restricted aperture, ISO sensitivity, and shutter speed ranges, which existing solutions like ND filters or image sensors with reduced sensitivity do not fully address.
Innovation Solution
The implementation of a digital camera system that includes a saturation determination section, divided exposure time detection, and image processing components to apply additive combination and minus gain to image data acquired through divided exposures, allowing for the generation of combined image data without pixel saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If aperture is closed down to F22 and ISO sensitivity set to lowest and shutter speed set to highest, then exposure is reduced, but blown out highlights still occur in high brightness subjects
Solution Approach 1:
The exposure time is divided into multiple shorter intervals, with the imaging section performing multiple imaging operations. Each individual exposure captures part of the total light information, preventing pixel saturation that would occur with a single long exposure. The segmented exposures are then combined to achieve the desired effective exposure reduction.
Solution Approach 2:
The imaging section performs periodic imaging operations at divided exposure intervals rather than a single continuous exposure. This periodic action allows the system to capture multiple frames at reduced individual exposure levels, avoiding saturation while maintaining the ability to achieve proper overall exposure through combination.
2Illumination intensity
If ND filter is inserted to reduce light amount, then correct exposure is achieved, but fitting filter to lens is troublesome
Solution Approach 1:
The patent replaces the mechanical ND filter system with a digital processing system. Instead of physically inserting a filter to reduce light, the imaging section performs multiple exposures at shorter durations and combines them digitally. This substitution eliminates the need for mechanical filter installation while achieving the same light reduction effect through computational methods.
Solution Approach 2:
The system creates multiple copies of the imaging operation at different exposure intervals rather than using a single physical filter. Each imaging operation captures a portion of the light information, and these copies are combined digitally to achieve the effective light reduction that would otherwise require an ND filter.
3Illumination intensity
If image sensor eliminates electrical charge signals to lower sensitivity, then shooting with reduced sensitivity is achieved, but hardware modification is required
Solution Approach 1:
The patent makes the exposure time dynamic and adjustable without modifying the image sensor hardware. By varying the exposure duration and performing multiple exposures at divided intervals, the system dynamically controls the effective sensitivity. This approach provides flexible sensitivity adjustment through software control rather than fixed hardware modifications.
Solution Approach 2:
The system changes the exposure time parameter and performs multiple imaging operations with different exposure durations. By adjusting these parameters and combining the results, the effective sensitivity is modified without changing the physical sensor characteristics. This allows sensitivity adjustment through parameter variation rather than hardware modification.
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 enables the capture of images with reduced output equivalent to using an ND filter or lower ISO sensitivity without actual hardware modifications, preventing blown-out highlights and extending the dynamic range of the camera.
Implementation Method 1
by eliminating some electrical charge signals that have been photoelectrically converted by photodiodes of the image sensor
Data Source
AI summary
An imaging device of the present invention comprises an additive combination for subjecting image data to additive combination, a gain application section for applying minus gain image data that has been subjected to additive combination by the additive combination section, an additive combination section for, at the time of imaging in the imaging section, respectively subjecting a plurality of image data, that have been acquired by divided exposure at the divided exposure time, to additive combination to create combined image data, and a gain application section for applying the minus gain to the combined image data to create taken image data.