Flicker Detection in Image Pickup Apparatus
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Solution Overview
Problem
Existing image pickup apparatuses struggle to accurately determine light amount change characteristics under flickering light sources, especially when the light amount change is irregular, leading to exposure unevenness and color temperature variations in images.
Innovation Solution
An image pickup apparatus equipped with a photometry unit, calculation units to determine evaluation values based on photometric values at different intervals, and a determination unit to assess whether the light changes at specific frequencies, ensuring accurate phase relationship analysis for flicker detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high shutter speed is used to photograph under dark environment, then image blurring is reduced, but exposure unevenness and color temperature variation occur under flickering light sources
Solution Approach 1:
The system performs preliminary detection of flicker frequency and light amount change characteristics before image capture. By analyzing photometric values at multiple time intervals and determining the light amount change period, the system prepares the optimal shutter timing in advance, ensuring that the exposure timing is pre-adjusted to coincide with the maximum light amount timing, thereby preventing exposure unevenness while maintaining high shutter speed
Solution Approach 2:
The system continuously monitors photometric values and provides feedback on light amount changes. By calculating evaluation values based on photometric values at different intervals and comparing them to determine flicker frequency, the system creates a closed-loop control that adjusts exposure timing based on real-time light source behavior, ensuring consistent exposure quality under flickering conditions
2Device complexity
If conventional flicker detection method is used assuming sine curve light amount change, then detection is simple, but accuracy deteriorates when light amount changes irregularly
Solution Approach 1:
Instead of assuming a fixed sine curve model, the system dynamically determines the light amount change period by analyzing actual photometric values. By calculating evaluation values at multiple time intervals (first interval, second interval, third interval) and determining the period that maximizes the correlation between expected and actual light amount changes, the system adapts to irregular flicker patterns while maintaining detection accuracy
Solution Approach 2:
The system transitions from one-dimensional sine curve assumption to multi-dimensional analysis by evaluating photometric values at multiple time intervals and considering multiple possible periods. By analyzing the relationship between photometric values at different intervals and determining the light amount change period through comparative evaluation, the system captures the complex temporal behavior of irregular flicker that cannot be represented by a simple sine model
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 high-accuracy determination of light amount change characteristics, effectively reducing exposure and color unevenness in images captured under flickering light sources.
Implementation Method 1
a photometry unit configured to acquire a plurality of photometric values by periodically performing photometry at fixed time intervals
Data Source
AI summary
An image pickup apparatus capable of determining a light amount change characteristic at the time of photographing with high accuracy. A light amount change period of light from a photometric target is determined, based first and second evaluation values calculated, respectively, based on a predetermined photometric value, and each of photometric values at first and second intervals causing the photometric values to be in the same phase relationship and the opposite phase relationship with the predetermined photometric value, respectively, in a case where the light from the photometric target changes at a predetermined frequency. It is determined whether or not the light from the photometric target changes at a light amount change period corresponding to the predetermined frequency.