Polarizer-Based Orientation Sensor for Digital Cameras
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Solution Overview
Problem
Existing orientation sensors for digital still cameras, such as mechanical tilt switches, are physically large and environmentally hazardous, making them unsuitable for modern digital still cameras, and require manual rotation of portrait-oriented photographs, which is time-consuming and inconvenient.
Innovation Solution
An orientation sensor system using at least two polarizers with different orientations and associated photodetectors, capable of determining the camera's orientation by processing output signals from photodetectors when exposed to polarized light, allowing automatic correction of image orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical tilt switches (mercury or ball based) are used for orientation sensing, then orientation measurement capability is achieved, but device size becomes large and environmental hazards arise
Solution Approach 1:
The patent replaces mechanical tilt switches (mercury or ball based) with an optical system comprising polarizers and photodetectors. This substitution eliminates moving parts and hazardous materials while maintaining orientation sensing capability through optical polarization detection, directly resolving the environmental hazard issue without sacrificing measurement precision
Solution Approach 2:
The patent changes the physical state and measurement approach from mechanical position detection to optical polarization parameter detection. By measuring the polarization state of light reflected from or transmitted through the target, the system achieves orientation sensing without mechanical components, thereby eliminating environmental hazards associated with mercury or ball-based mechanical switches
2Measurement precision
If mechanical tilt switches are used for orientation sensing, then orientation measurement capability is achieved, but device size becomes large
Solution Approach 1:
The patent replaces bulky mechanical tilt switches with a compact optical system using polarizers and photodetectors. This substitution dramatically reduces the physical footprint of the orientation sensing mechanism while maintaining measurement precision, enabling integration into modern compact digital still cameras
Solution Approach 2:
The patent extracts the orientation sensing function from a separate mechanical component and integrates it directly into the camera's optical path using polarizers positioned in the light path. This integration eliminates the need for separate mechanical sensing devices, reducing overall device size while preserving orientation measurement capability
3Reliability
If manual rotation of portrait photographs is required, then correct orientation can be achieved, but time consumption increases
Solution Approach 1:
The patent performs preliminary action by capturing the camera's orientation information at the moment of photograph acquisition using the polarizer-based orientation sensor. This orientation data is stored alongside the image, enabling automatic orientation correction during display or processing, thereby eliminating the need for manual rotation and saving user time while ensuring correct orientation
Solution Approach 2:
The patent implements feedback by using the orientation sensor to continuously monitor camera orientation and providing this information to the image processing system. This feedback loop enables automatic orientation correction of captured images based on the actual camera orientation at the time of capture, eliminating manual intervention and ensuring photographs are always displayed in the correct orientation
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 automatic and efficient determination of image orientation, reducing the need for manual rotation and eliminating the need for large mechanical components, while being environmentally friendly and suitable for integration within modern digital still cameras.
Implementation Method 1
at least two polarizers with different orientations... when the image sensor is exposed to polarized light
Implementation Method 2
a photodetector associated with each polarizer... output signals of the photodetectors
Data Source
AI summary
An orientation sensor for use with an image sensor is provided, which includes at least two polarizers with different orientations and associated photodetectors and a signal processing unit. The orientation sensor can be incorporated in a digital camera. When the camera is exposed to daylight, which is polarized, the relative outputs from the differently oriented polarizers can be compared to record the orientation of the camera. This orientation can be stored with the image data so that a user does not have to manually change the orientation of an image on an image display device.