Scanning Aperture Shutter Fill Flash Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic imaging devices face challenges in controlling the integration of light signals and achieving proper illumination balance between natural and artificial light sources, especially when using a fill flash function for scenes with near-field objects of limited brightness and far-field backgrounds of greater brightness.
Innovation Solution
An electronic camera system with a scanning aperture shutter, photocells for sensing visible and infrared spectrum energy, and an exposure control system that adjusts the flash unit based on sensed light energy to control the amount of fill flash energy relative to ambient light, ensuring balanced illumination by illuminating the flash unit when a predetermined amount of ambient light is sensed and extinguishing it when infrared energy is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a flash unit is used to illuminate near-field objects, then the illumination balance between near-field and far-field is improved, but the integration time control becomes more complex
Solution Approach 1:
The patent divides the aperture control into two separate scanning apertures: one for the image capture device and another for the photocell. This segmentation allows independent control of light exposure for imaging versus flash triggering, simplifying the integration time control while maintaining illumination balance.
Solution Approach 2:
The photocell performs preliminary measurement of ambient light energy before the actual image capture. Based on this preliminary action, the system determines whether flash illumination is needed and sets the appropriate integration time, thereby simplifying the overall control process.
2Measurement precision
If separate apertures are provided for image capture and photocell sensing, then the control of flash timing is improved, but the device structure becomes more complex
Solution Approach 1:
The patent employs scanning apertures that dynamically open and close at precise moments during the exposure cycle. This dynamic operation allows the system to achieve accurate flash timing control without requiring complex static mechanical structures, as the apertures are controlled through coordinated scanning motion.
Solution Approach 2:
The scanning aperture mechanism serves multiple functions: it controls light to the image capture device, controls light to the photocell, and coordinates flash timing. This multi-functionality reduces the need for separate dedicated structures for each function, thereby managing overall device complexity.
3Illumination intensity
If the photocell measures ambient light to control flash illumination, then the illumination balance is improved, but the integration of multiple signals becomes more complex
Solution Approach 1:
The photocell provides feedback about the ambient light energy level to the exposure control system. This feedback mechanism allows the system to automatically adjust flash illumination and integration time to achieve proper exposure balance, simplifying the overall signal integration process through automated control logic.
Solution Approach 2:
The system changes operational parameters (integration time, flash duration, aperture position) based on photocell measurements. By dynamically adjusting these parameters, the system achieves illumination balance without complex signal processing, as the control is based on straightforward parameter modification rather than complex signal integration.
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 system effectively balances illumination between natural and artificial light sources, ensuring proper image capture by dynamically controlling the flash unit in response to sensed light energy, thereby improving image quality and minimizing shadows in near-field objects.
Implementation Method 1
a photocell adapted for sensing light energy received from the image scene
Implementation Method 2
a scanning aperture shutter located to control light energy received by the electronic image capture device from the image scene
Data Source
AI summary
A method and camera for electronic image capture provide an electronic image capture device, a scanning aperture shutter located to control light energy received by the image capture device, a flash unit oriented to illuminate an image scene, a photocell unit adapted for sensing visible spectrum energy and infrared spectrum energy received from the image scene, and an exposure control system responsive to the photocell unit and operatively connected to the scanning aperture shutter and the flash unit. The exposure control system is adapted to control an amount of fill flash energy received from the image scene in relation to visible ambient light energy received from the image scene during image capture by illuminating the flash unit once a predetermined amount of ambient visible spectrum energy is sensed by the photocell unit and by extinguishing the flash unit once a predetermined amount of infrared energy is sensed by the photocell unit.