Imaging Apparatus Exposure Control and Dark Area Gradation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional imaging apparatuses struggle with appropriate exposure adjustment, particularly in subjects with large luminance differences, leading to underexposed dark areas and inadequate gradation compression.
Innovation Solution
An imaging apparatus that divides the subject into regions for photometry, calculates exposure control values based on these regions, compares them to determine optimal exposure, and adjusts image data gradation to improve lightness, using a photometry unit, calculating units, and a light emission part to correct exposure and gradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a constant exposure target value is used regardless of luminance pattern, then the exposure control is simplified, but appropriate exposure adjustment cannot be performed when optimum exposure adjustment differs according to luminance pattern
Solution Approach 1:
The exposure target value is made dynamic by switching between multiple predetermined values based on the luminance pattern detected in the subject image. The control unit selects different target values corresponding to different luminance patterns (e.g., high-key, low-key, standard scenes), allowing the system to adapt to various shooting conditions while maintaining a relatively simple control structure.
2Manufacturing precision
If gradation compression is applied to improve dark area visibility, then dark area detail is improved, but over-correction may occur leading to unnatural image quality
Solution Approach 1:
The lightness improvement amount is dynamically adjusted by changing the parameter k in the linear function y=kx based on the detected luminance pattern. Different luminance patterns result in different k values, which control the degree of lightness improvement. This prevents over-correction by selecting appropriate correction strength for each scene type, maintaining natural image quality while improving dark area visibility.
3Illumination intensity
If exposure control value is increased to capture dark areas, then dark area visibility is improved, but highlight areas may become overexposed
Solution Approach 1:
The image processing applies different treatment to different luminance regions. The lightness improvement is selectively applied to dark area pixels (those with luminance below a threshold) while preserving highlight areas. This local processing approach allows dark areas to be brightened without affecting already bright regions, preventing highlight overexposure.
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 optimal exposure adjustment and correction of dark area gradation, preventing over-correction and ensuring improved image quality by providing a lightness improvement amount based on imaging sensitivity and shooting conditions.
Implementation Method 1
a photometry unit (12) dividing a subject into a plurality of regions and performing a photometry
Data Source
AI summary
An imaging apparatus includes a photometry unit dividing a subject into a plurality of regions and performing a photometry, a first calculating unit calculating a first control value based on a photometry result of the photometry unit, a comparing unit comparing the first control value with a maximum value of photometry values in the plurality of regions, a second calculating unit correcting the first control value depending on a comparison result by the comparing unit to calculate a second control value, an image pickup unit picking up an image of the subject according to the second control value and generates an image data, and a third calculating unit calculating a lightness improvement amount for a correction of dark area gradation of the image data depending on the comparison result. Therefore, optimum exposure adjustment and correction of dark area gradation can be performed depending on the subject.