Optical Click Detection via Image Convolution
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Solution Overview
Problem
There is a need for input devices that can optically detect click events without increasing space requirements, especially in portable electronic devices where multiple functionalities need to be combined into a single device.
Innovation Solution
An apparatus with a contact surface, an image capture system, and a processing system that captures images and convolves them with a two-dimensional circularly symmetric spatial bandpass filter to differentiate between in-contact and out-of-contact times, generating a select signal based on click event predicates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic transducers or mechanical buttons are used to detect click events, then click detection functionality is achieved, but device size and space requirements increase
Solution Approach 1:
The patent combines click detection functionality with the existing optical navigation sensor and contact surface, merging multiple input functions into a single integrated system. The same image capture system used for tracking finger movement during optical navigation is also used to detect click events, eliminating the need for separate mechanical buttons or transducers.
Solution Approach 2:
The contact surface serves multiple functions: it acts as both the interaction surface for optical navigation tracking and the detection surface for click events. The image capture system similarly performs dual functions by capturing images for both navigation tracking and click detection, making the system multi-functional without requiring additional components.
2Adaptability or versatility
If multiple input device functionalities are combined into a single device, then device versatility improves, but space requirements and complexity increase
Solution Approach 1:
The system achieves multiple input functions (optical navigation and click detection) through a single unified hardware platform. The image capture system and contact surface are used for both navigation tracking and click event detection, providing versatility without requiring separate subsystems for each function.
Solution Approach 2:
The patent replaces traditional mechanical click detection mechanisms (buttons, switches, or electromechanical transducers) with an optical detection system. By using image analysis of the contact surface, the system eliminates mechanical components and their associated complexity while maintaining click detection functionality.
3Volume of moving object
If optical navigation sensors are used instead of electromechanical transducers, then device size is reduced, but click detection capability is lost
Solution Approach 1:
The optical navigation sensor system is extended to perform dual functions: tracking finger movement during navigation and detecting click events through image analysis of the contact surface. This multi-functional use of the optical system maintains compact device size while adding click detection capability.
Solution Approach 2:
The patent replaces mechanical or electromechanical click detection mechanisms with an optical imaging-based detection system. By analyzing changes in the captured images of the contact surface, the system achieves click detection without mechanical components, maintaining the size advantages of optical navigation while adding selection functionality.
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 efficient optical detection of click events with robust false alarm avoidance, suitable for integration with other input device functionalities without increasing space, suitable for compact electronic devices.
Implementation Method 1
optical navigation technology that measures changes in position by acquiring a sequence of images of light reflecting from a surface
Implementation Method 2
The processing system convolves the captured images with a two-dimensional circularly symmetric spatial bandpass filter to produce corresponding filtered images
Data Source
AI summary
Apparatus and method of optically detecting click events are described. Images of a contact surface are captured at respective capture times. The captured images are convolved with a two-dimensional circularly symmetric spatial bandpass filter to produce corresponding filtered images each including a set of pixels with respective pixel value magnitudes. Based on the pixel value magnitudes of the corresponding filtered images, each of the capture times is assigned to one of an in-contact time class during which the contact surface is determined to be in-contact with a user's finger and an out-of-contact time class during which the contact surface is determined to be out-of-contact with the user's finger. A select signal indicating that the contact surface has been touched to make a selection is generated based on a click event predicate defining at least one condition on the time classes respectively assigned to successive ones of the capture times.