Camera AF Auxiliary Illumination Dynamic Brightness Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In digital cameras, the constant emission of AF auxiliary illumination leads to saturation and inaccurate photometric values when the object is close, resulting in inefficient AF control and wasteful energy usage.
Innovation Solution
The camera adjusts the emission amount of AF auxiliary illumination based on the focus position, dimming it for close-range objects and increasing it for longer ranges, using a CCD or CMOS to measure reflected light and control the emission current or DUTY ratio, ensuring optimal light quantity and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the emission amount of AF auxiliary illumination is kept constant, then the AF control can be performed in dark environments, but the solid-state image pickup element becomes saturated when the object is at close position, resulting in inaccurate photometric values
Solution Approach 1:
The patent applies dynamics by making the emission amount of AF auxiliary illumination variable rather than constant. The emission amount is dynamically adjusted based on the focus position: when the object is at close position, the emission amount is reduced to prevent saturation; when the object is at long range, the emission amount is increased to provide sufficient illumination in dark environments. This dynamic adjustment resolves the contradiction between maintaining adequate illumination and avoiding saturation.
Solution Approach 2:
The patent changes the parameter of emission amount based on focus position. By detecting the focus position and corresponding photometric values, the system adjusts the emission amount parameter to appropriate levels. This parameter change enables the system to adapt to different object distances, preventing saturation at close range while ensuring sufficient illumination at long range.
2Illumination intensity
If the emission amount of AF auxiliary illumination is increased for close-range objects, then sufficient illumination is provided, but the emission current becomes wasteful and energy consumption increases
Solution Approach 1:
The system dynamically adjusts the emission amount based on focus position detection. When the object is detected at close position, the emission amount is automatically reduced, preventing wasteful energy consumption. When the object is at long range in dark conditions, the emission amount is increased to provide necessary illumination. This dynamic control eliminates the waste of emission current while ensuring adequate illumination when needed.
Solution Approach 2:
The emission amount parameter is changed according to focus position. By adjusting this parameter based on detected object distance and photometric values, the system optimizes energy usage - reducing emission at close range where it would be wasteful, and increasing emission at long range where it is necessary for proper AF control in dark environments.
3Loss of energy
If the emission amount of AF auxiliary illumination is reduced for close-range objects, then energy is saved, but insufficient illumination is provided for accurate AF control in dark environments
Solution Approach 1:
The system dynamically adjusts emission amount based on focus position and photometric value detection. When objects are at close position, emission is reduced to save energy while AF control remains accurate because close-range objects typically have sufficient reflected light. When objects are at long range in dark conditions, emission is increased to ensure adequate illumination for reliable AF control. This dynamic response maintains reliability while optimizing energy efficiency.
Solution Approach 2:
The emission amount parameter is adaptively changed based on focus position and environmental lighting conditions. The system monitors photometric values and adjusts emission accordingly, ensuring that AF control accuracy is maintained through parameter optimization rather than constant high emission, thus achieving both reliability and energy efficiency.
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 allows for accurate AF control and energy savings by tailoring the emission amount to the object's position, preventing saturation and improving focus detection accuracy.
Implementation Method 1
the AF auxiliary illumination reflected from the object is measured
Implementation Method 2
an image pickup device such as a CCD, CMOS and so on
Data Source
AI summary
The present invention provides a camera with AF auxiliary illumination in which the focus position of an image taking lens is AF controlled to bring an object into focus, based on contrast information of an image acquired from an image pickup device, and if the photometric value of the object is less than a predetermined value, an AF auxiliary illumination is directed to the object, wherein the AF auxiliary illumination reflected from the object is measured, in which if the photometric value is greater than or equal to a specified value, the AF auxiliary illumination is dimmed out, and the emission amount of the AF auxiliary illumination is controlled based on the focus position of the image taking lens.