Psychohaptic Vibrotactile Encoding With Wavelet Compression

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Solution Overview

Problem

Current encoding and decoding technologies, such as MP3 and JPEG, are not suitable for vibrotactile signals due to their audio and video-centric design, resulting in high distortion and increased data transmission, failing to efficiently compress and accurately transmit tactile sensations.

Innovation Solution

An encoding apparatus and method utilizing a discrete wavelet transform, psychohaptic model, and set partitioning in hierarchical trees (SPIHT) algorithm to generate a bitstream that adapts to human haptic perception, reducing data transmission while maintaining signal quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If audio and video encoding technologies (MP3, JPEG) are used for vibrotactile signals, then the encoding process is simple and familiar, but the distortion is high and signal quality deteriorates

Engineering Contradiction:
Improveencoding process simplicityVSAvoidsignal quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent transforms vibrotactile signals from the time domain to the frequency domain using Fourier transform, and then to the wavelet domain using discrete wavelet transform. This parameter transformation enables adaptive quantization based on human haptic perception characteristics, significantly reducing distortion while maintaining signal quality. The psychoacoustic model parameters are used to guide the quantization process, making it both simple to implement and highly effective.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If audio and video encoding technologies (MP3, JPEG) are used for vibrotactile signals, then the encoding implementation is straightforward, but data transmission volume increases

Engineering Contradiction:
Improveencoding implementationVSAvoiddata transmission volume
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent applies discrete wavelet transform to decompose the signal into different frequency subbands, then uses a psychoacoustic model to identify and prioritize important frequency components. By quantizing and encoding only the significant coefficients while discarding or coarsely encoding less important ones, the system achieves high compression ratios. The implementation remains straightforward as it builds upon familiar transform-based encoding frameworks.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If conventional encoding methods are used for vibrotactile signals, then the system complexity is low, but the transmission accuracy deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidtransmission accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent introduces a psychoacoustic model as an intermediary between the signal transformation and quantization stages. This model analyzes the frequency domain representation and generates quantization control signals that guide the encoding process to preserve perceptually important information. The intermediary layer adds minimal complexity while dramatically improving transmission accuracy by enabling adaptive, perception-based compression.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Area of stationary object

If audio and video encoding technologies are adapted for tactile signals, then existing technology can be reused, but perceptual distortion increases

Engineering Contradiction:
Improvetechnology reuseVSAvoidperceptual distortion
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by treating different frequency subbands of the vibrotactile signal differently based on human haptic perception characteristics. The psychoacoustic model identifies which frequency regions are perceptually important and allocates more bits to encode them with higher precision, while using coarser quantization for less important regions. This localized, adaptive approach minimizes perceptual distortion while maintaining efficient compression.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11113934B2Encoding/decoding apparatuses and methods for encoding/decoding vibrotactile signals
Publication Date: 2021.09.07 TECHNISCHE UNIVERSITAT MUNCHEN
  • US11113934B2 patent drawing
  • US11113934B2 patent drawing
  • US11113934B2 patent drawing

AI summary

An encoding apparatus for encoding a vibrotactile signal includes a first transforming unit configured to perform a discrete wavelet transform of the signal, a second transforming unit configured to generate a frequency domain representation of the signal, a psychohaptic model unit configured to generate at least one quantization control signal based on the generated frequency domain representation of the sampled signal and on a predetermined perceptual model based on human haptic perception, a quantization unit configured to quantize wavelet coefficients resulting from the performed discrete wavelet transform and adapted by the quantization control signal, a compression unit configured to compress the quantized wavelet coefficients, and a bitstream generating unit configured to generate a bitstream corresponding to the encoded signal based on the compressed quantized wavelet coefficients. The subject matter described herein also includes a corresponding decoding unit, an encoding method and a decoding method.