Interactive Projector Contact Detection Using Light Patterns
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Solution Overview
Problem
Interactive projectors using self-light emitting pointing elements, such as pens, face low detection accuracy due to light reflection on the screen surface, affecting the precision of contact detection.
Innovation Solution
The system employs both self-light emitting and non-light emitting pointing elements, using different detection methods: the self-light emitting elements are detected based on light emitting patterns, while non-light emitting elements are detected using three-dimensional position data and near-infrared detection light, improving overall accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a self-light emitting pointing element (pen) is used to detect contact with the screen, then the pointing element can be easily tracked in non-contact state, but light emitted by the pen is reflected on the screen surface in contact state, reducing detection accuracy
Solution Approach 1:
The detection method is segmented into two distinct approaches: one for self-light emitting pointing elements (using light emitting pattern analysis) and another for non-light-emitting pointing elements (using three-dimensional position detection). This segmentation allows each detection method to be optimized for its specific type, resolving the contradiction by applying the appropriate method based on the pointing element characteristics.
Solution Approach 2:
Instead of trying to detect contact by observing the absence or change of light emission from the pen, the invention inverts the approach by detecting contact through analysis of the light emitting pattern itself. The light emitting pattern changes characteristically when the pen contacts the screen, and this pattern change is used as the detection criterion rather than trying to detect the light reflection interference.
2Measurement precision
If a single detection method is used for all pointing elements, then the system structure is simple, but detection accuracy varies between self-light emitting and non-light-emitting pointing elements
Solution Approach 1:
The contact detection unit is designed with multi-functionality to handle both self-light emitting and non-light-emitting pointing elements. It automatically selects and applies the appropriate detection method based on the type of pointing element being used, achieving universal applicability while maintaining high detection accuracy for each type without requiring separate dedicated systems.
Solution Approach 2:
The detection system changes its operational parameters based on the pointing element type. For self-light emitting elements, it analyzes light emitting patterns; for non-light-emitting elements, it uses three-dimensional position data. This parameter change allows the single contact detection unit to optimize its detection approach for different element types, maintaining accuracy without increasing overall system complexity.
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 enhances the detection accuracy of contact with the projected screen for both types of pointing elements, providing a more reliable user interface experience.
Implementation Method 1
a self-light emitting pointing element 70 including a light-emitting portion 77 which emits pointing element signal light PSL in different light emitting patterns between at the time of contacting the projected screen PS and at the time of non-contacting the projected screen PS
Implementation Method 2
in a case where a pen which emits light is used as the pointing element, light emitted by the pen is reflected on a screen surface
Implementation Method 3
a detection light irradiation unit 410 that irradiates the projected screen with detection light used for detection of the non-light-emitting pointing element
Data Source
AI summary
An interactive projector includes a projection unit that projects the projected screen on a screen surface, a plurality of cameras that include a first camera and a second camera capturing an image of an area of the projected screen, a position detection unit that detects a three-dimensional position of the pointing element with respect to the projected screen based on a plurality of images including the pointing element of which the image is captured by the plurality of cameras, and a contact detection unit that detects contact with the projected screen of a pointing element, and the contact detection unit detects contact of the self-light emitting pointing element with the projected screen based on the light emitting pattern and detects contact of the non-light-emitting pointing element with the projected screen based on the three-dimensional position detected by the position detection unit.