Virtual Instrument Stick Motion Detection via Image Difference Thresholding
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Solution Overview
Problem
Conventional performance apparatuses often detect unintentional player motion as intended, leading to unwanted sound generation when playing virtual musical instruments.
Innovation Solution
A performance apparatus comprising a stick unit with sensors, an image pickup unit, and a center unit that compares positions between consecutive images to differentiate between intentional and unintentional motion, preventing sound generation based on unintentional movements by setting the previous position as the present position when minor differences are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the performance apparatus detects player motion based on position changes between consecutive images, then the responsiveness and realism of the virtual instrument performance is improved, but unintentional player motions are incorrectly detected as intended playing motions, causing unwanted sound generation
Solution Approach 1:
The patent introduces a threshold parameter (predetermined value) for position difference detection. By comparing the position difference between consecutive images against this threshold, the system distinguishes between intentional playing motions (larger displacements) and unintentional motions (smaller displacements). This parameter-based filtering resolves the contradiction by maintaining responsive detection while filtering out false positives from unintentional movements.
2Measurement precision
If the apparatus uses built-in sensors in performance members to detect playing motions, then the detection precision and reliability are improved, but the player feels constraints and the system cannot distinguish intentional from unintentional motions
Solution Approach 1:
The patent replaces the mechanical sensor-based detection system with an optical image processing system. Instead of using built-in sensors in the performance members that require physical attachment and constrain the player, the system uses an image pickup unit to capture images and process position information computationally. This substitution maintains detection precision through image analysis while eliminating the physical constraints and complexity of sensor integration, allowing players to use natural motions without feeling constrained by embedded devices.
Data Source
AI summary
A performance apparatus prevents a player's unintentional motion from being detected as a playing, thereby generating no sound, when the player plays a virtual musical instrument. The performance apparatus has a player operated stick, a ROM for storing layout information, which correlates plural areas set on a virtual plane to tone colors, respectively, an image sensor for continuously taking pickup images of a subject including the stick, and a CPU for calculating a difference image between a first pickup image and a second pickup image taken prior to the first pickup image and for detecting an operating position of the stick based on the difference image. A CPU refers to the ROM to specify a tone color correlated to the area corresponding to the operating position detected by the CPU. And a sound source generates a tone of the tone color specified by the CPU.