No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Lossy Compression of Haptic Data by Using DCT
Abstract
In this paper, lossy data compression of haptic data is presented and the results of its application to a motion copying system are described. Lossy" data compression has been studied and practically applied in audio and image coding. Lossy data compression of the haptic data has been not studied extensively. Haptic data compression using discrete cosine transform (DCT) and modified DCT (MDCT) for haptic data storage are described in this paper. In the lossy compression, calculated DCT/MDCT coefficients are quantized by quantization vector. The quantized coefficients are further compressed by lossless coding based on Huffman coding. The compressed haptic data is applied to the motion copying system and the results are provided.
Images are now employed as data in a variety of applications, including medical imaging, remote sensing, pattern recognition, and video processing. Image compression is the process of minimizing the size of images by removing or grouping certain parts of an image file without affecting the quality, thereby saving storage space and bandwidth. Image compression plays a vital role where there is a need for images to be stored, transmitted, or viewed quickly and efficiently. There are different techniques through which images can be compressed. This paper mainly focuses on the survey of basic compression techniques available and the performance metrics that are used to evaluate them. In addition to this, it also provides a review of important pieces of the literature relating to advancements in the fundamental lossy and lossless compression algorithms.
This paper proposes haptic data quantization in communication systems in which all haptic information is transmitted through a network. From an engineering view point, bilateral control with master and slave manipulators has been studied to reproduce kinesthetic sensations. However, in scaled haptic transmission applications, communication constraints are a serious problem especially in a microspace. Moreover, communication delay deteriorates the performance of haptic sensation transmission when a large amount of data flows into a communication line. To reduce the communication delay caused by the amount of information and communication constraints, a data quantization method is discussed. Along with audio and visual information, an encoding technique is often applied to haptic information. In particular, a delta-sigma modulator based on a static quantizer has low computational complexity, and it reduces the quantization error in a low-frequency domain. Therefore, haptic sensation transmission with the modulator is constructed in quantized scaling-bilateral control. According to the analyses of hybrid parameters including the interference of a quantization error and a communication delay, the performance of haptic sensation transmission is evaluated. In experiments with a communication delay, stable operation and improved performance are achieved to reduce all information: current, position, and force.
This paper proposes a new motion-copying system which uses statistical approaches for recording and reproducing of human tasks. In conventional motion-copying systems, haptic data of human motions is recorded directly to the database at every sampling. As a result, the amount of haptic data for the database is large in general. In addition to that, it is hard to segment and reorganize the recorded human motions. Therefore, the motion-copying system proposed in this paper uses Gaussian mixture model (GMM) to model human motions for the recording. The modeled GMM are recorded in the database instead of raw haptic data. Therefore, the recorded data size is reduced compared with conventional methods. Furthermore, the automatic segmentation and reorganization of recorded human motions are possible. Proposed method uses Gaussian mixture regression (GMR) to retrieve haptic information from GMM for the reproducing. The validity of the proposed method was confirmed through 1DOF motion-copying experiment.
In this paper, a quantization scheme for haptic data compression is proposed and the results of its application to a motion copying system are described. The data compression of image and audio data has been researched a lot. However, the data compression of haptic data has not been much researched yet although the amount of haptic data is large in general. The discrete cosine transform (DCT) is used for the lossy compression of haptic data in this paper. A new quantization scheme using characteristics of DCT is proposed. By using a proposed method, a larger signal-to-noise ratio compared to conventional method is achieved. In the experiment, the validity of the proposed method was verified.
Σ-Δ estimation is a simple non linear method of background estimation used in the field of image processing. We propose the method of data transmission using the Σ-Δ modulation under narrow bandwidth, which degrades the performance due to time-discretization. In this paper, the Σ-Δ estimation is used as a method of motion detection of motors, and high priority is added to detected data. Hierarchical Token Bucket, which controls traffic in a link, discrimates motion data, and handles the packet with high priority preferentially. The motion detection algorithm based on traffic contonl is implemented into two degree-of-freedom robots to verify the validity of the proposed method. Effectiveness of the proposed method is verified through experiments.
Immersive environments provide an artificial world to surround users. These environments consist of a composition of various types of immersidata: unique data types that are combined to render a virtual experience. To construct such an environment, immersidata acquisition is indispensable for storage and future query. However, this is challenging because of the real time demands and sizeable amounts of data to be managed. We propose and evaluate alternative techniques for achieving efficient sampling and compression of one immersidata type, the haptic data, which describes the movement, rotation, and force associated with user-directed objects in an immersive environment. Our experiments identify the benefits and limitations of various techniques in terms of their data storage, bandwidth and accuracy.
Telepresence systems are often deployed in scenarios where communication bandwidth is limited. Consequently, data exchanged between operator and teleoperator has to be reduced. In case of haptic telepresence, data reduction has an influence on the stability of the overall system. This paper provides a step towards a systematic framework for communication data bandwidth reduction in haptic telepresence systems discussing stability for a class of lossy data reduction (LDR) algorithms. Simulation and experimental results validate the efficacy
In spite of the significant recent progress, the incorporation of haptics into virtual environments is still in its infancy due to limitations in the hardware, the cost of development, as well as the level of reality they provide. Nonetheless, we believe that the field will one day be one of the groundbreaking media of the future. It has its current holdups but the promise of the future is worth the wait. The technology is becoming cheaper and applications are becoming more forthcoming and apparent. If we can survive this infancy, it will promise to be an amazing revolution in the way we interact with computers and the virtual world. The researchers organize the rapidly increasing multidisciplinary research of haptics into four subareas: human haptics, machine haptics, computer haptics, and multimedia haptics
The paper proposes the transfer technique of haptic information under the narrow-band network. The bilateral controller through the low-rate network encounters the influence. In this paper, the compressors and the decompressors is implemented to the bilateral controller based on a motion copying system in order to solve the problems. The data compressors reduce an amount of the data, which flows between a master system and a slave system in the bilateral controller. The reaction force between the master and the slave becomes stable even if the data transfer rate is low in the network. The paper confirms that the bilateral controller using the compressors and the decompressors normally operates. The viability of the proposed method is confirmed by experiments.
In this paper, a medical forceps system with tactile and force feedback ability desired by surgical robots is developed. Bilateral teleoperation systems can decompose into the common and the differential modes in acceleration based controller. The force servoing is attained in the common mode and the position error is regulated in the differential mode. In order to consider the conformity of force with position, the force servoing and the position regulator are integrated in the acceleration. The acceleration based controller is realized by using the disturbance observer. The disturbance observer makes a motion system to be an acceleration control system.In this paper, two evaluation indices of bilateral teleoperation are defined by analyzing 4ch matrix; “reproducibility” and “operationality”. The forceps realizes wide frequency response for high force reproducibility. The experimental results show the viability of the proposed design and analysis methods.
In recent years, skill preservation of an expert and skill education for young technical workers have been se-rious issues in medical and production fields. The best way which young technical workers learn the ripe skill is that an expert teaches them. However, unfortunately, experts have lessened in these years. So, if digital skill pre-servation like a haptic database is attained, it may become an innovative solution of the above problem. Thus, as the fundamental technology for development of the haptic database, this paper proposes abstraction and repro-duction methods on bilateral control of real world force sensation, and reconstruction of real world environment as well. In the abstraction mode, a master-slave system is composed, and the action-reaction law is attained through bilateral control. Later, based on acceleration information, the force, position and velocity of both mas-ter and slave systems are estimated and obtained. In the reconstruction mode, an environmental model is recon-structed based on the obtained data from real-world. Next, by using reproduction mode on master side, the ope-rator would feel the force sensation from the obtained environmental model. Here, the proposed system is able to store the bilateral real-world force sensation to a sensation database. Finally, the experimental results show the validity of the proposed method.
In this paper, data compression and decompression method for real-world haptics using discrete cosine transform (DCT) is proposed and applied to a motion copy system. Haptics recently has attracted much interests and been and studied by many researchers. The technology of real-world haptics based on bilateral control systems is expected to apply teleoperation for precise task, education system for human skill, etc. Various researches have been studied for the real-world haptic, haptic data compression for data storage has been not studied much yet. The haptic data is compressed using DCT to reduce the data size. The validity is shown by applying to motion copy system. The data size was reduced less than a quarter, and degradation of decompressed data was little.
Recently, motion copying technologies are important elements in order to succeed production engineering of expert engineers. The paper proposes a novel motion copying system. The motion copying system consists of a motion saving system and motion loading system. The motion saving system saves motion of human operator by bilateral controller using a quarry matrix. On the contrary, the motion loading system is realized by virtual-world master system and real-world slave system. The motion loading system operates according to saved position and force information, and reproduces saved motion. The proposed method realizes that the reproduced position and force corresponds to saved position and force data. The paper confirms that the motion saving system and motion loading system normally operates. The motion copying system achieves copy of motion of human operator.
Nowadays, with the coming of population aging, extractions of skilled human motion and human support techniques are needed in medical or production fields. This paper proposes a method for motion extraction and guide based on haptic information. Haptic information includes human action force and position response. Human action force and position response are sensed by using master-slave robot hand which is bilateral controlled. Skill motion is extracted as action modes and action energies calculated from human action force relationship and position response relationship. Action modes are modes which express action force and position response direction, and action energies are amplitude of each action mode. Motion guide system is composed of action force extraction and modal compliance controller which are designed based on action modes and action energies. The validity of the proposed methods is shown by the experimental results.
It is very important for robots working in unknown environment to recognize surface profile of the environment. This paper presents an extraction method of environmental surface profile based on environmental modes. Contact condition between a planar end-effector and the environment is also determined by using active motion which is named "groping motion" of the end-effector. The extraction method utilizes discrete Fourier transform (DFT) matrices as matrices transforming into environmental modes. The proposed method can be applied to a planar end-effector whose shape is an arbitrary polygon. Moreover, a compliance controller for attitude of a planar end-effector with 3 supporting points is proposed to realize stable contact motion with unknown environment. The validity of the proposed method is shown by the experimental results
This paper presents a model based prediction of haptic data signals for data compression purposes in virtual haptic teleinteraction environments. The proposed data reduction itself is based on psychophysical properties of human perception. This scheme can be used for Internet-based multimedia applications like haptics-supported games or virtual haptic explorations. Using our approach haptic data packet rate reduction of up to 95% without impairing immersiveness is achieved.
A new, oddly stacked, critically sampled, single side-band (SSB) [7] analysis/synthesis system based on Time Domain Aliasing Cancellation (TDAC) [1],[2] is described in this paper. The specifications for the analysis and synthesis filter responses are developed and a number of designs which satisfy the reconstruction requirements are described. The application of TDAC systems to Subband/Transform coding is also discussed and the objective performance of a 32 band coder using several different window designs is presented and compared with a coder based on Frequency Domain Aliasing Cancellation (FDAC) filter banks [3]-[5].
In this paper we review the role of digital filters for audio
coding. Most specifically we discuss the general subband/transform
coding framework used in state of the art perception-based audio coders.
Such strategies rely on the use of digital filter banks to decompose
signals into time-frequency components to achieve better source coding
gains by exploiting the signal redundancy and also facilitating the
direct use of psychoacoustic masking models on quantization noise
shaping to remove signal irrelevancy. The paper focuses on the use of
various digital filtering designs and implementation issues which have
found their place in audio coding. Examples of their roles and
computational requirements are illustrated by MPEG audio coding
standards
Motion control is now recognized as a key technology in mechatronics. The robustness of motion control will be represented as a function of stiffness and a basis for practical realization. Target of motion is parameterized by control stiffness which could be variable according to the task reference. However, the system robustness of motion always requires very high stiffness in the controller. The paper shows that control of acceleration realizes specified motion simultaneously with keeping the robustness very high. The acceleration is a bridge to connect such robustness and variable stiffness. For practical applications, a technique to estimate disturbance is introduced to make motion controller to be an acceleration controller. Motion control of flexible structure and identification of mechanical parameters are also described.
The demand for higher and higher quality images transmitted
quickly over the Internet has led to a strong need to develop better
algorithms for the filtering and coding of such images. The introduction
of the JPEG2000 compression standard has meant that for the first time
the discrete wavelet transform (DWT) is to be used for the decomposition
and reconstruction of images together with an efficient coding scheme.
The use of wavelets implies the use of subband coding in which the image
is iteratively decomposed into high- and low-frequency bands. Thus there
is a need for filter pairs at both the analysis and synthesis stages.
This paper aims in tutorial form to introduce the DWT, to illustrate its
link with filters and filterbanks and to illustrate how it may be used
as part of an image coding algorithm. It concludes with a look at the
qualitative differences between images coded using JPEG2000 and those
coded using the existing JPEG standard
A torque sensorless control for a multi-degree-of-freedom
manipulator is described. In the method, two disturbance observers are
applied to each joint. One is used to realize a robust motion
controller. The other is used to obtain a sensorless torque controller.
A robust acceleration controller based on the disturbance observer is
shown. To obtain the sensorless torque control, it is necessary to
calculate the reaction torque when the mechanical system performs a
force task. The calculation method for the reaction torque is explained.
Then the method is expanded to workspace force control in the
multi-degree-of-freedom manipulator. Several experimental results are
shown to confirm the validity of the proposed sensorless force
controller
A discrete cosine transform (DCT) is defined and an algorithm to compute it using the fast Fourier transform is developed. It is shown that the discrete cosine transform can be used in the area of digital processing for the purposes of pattern recognition and Wiener filtering. Its performance is compared with that of a class of orthogonal transforms and is found to compare closely to that of the Karhunen-Loève transform, which is known to be optimal. The performances of the Karhunen-Loève and discrete cosine transforms are also found to compare closely with respect to the rate-distortion criterion.
The objective of the paper is to provide an overview on recent trends and future perspectives in image and video coding. Here, I review the rapid development in the field during the past 40 years and outline current state-of-the art strategies for coding images and videos. These and other coding algorithms are discussed in the context of international JPEG, JPEG 2000, MPEG-1/2/4, and H.261/3/4 standards. Novel techniques targeted at achieving higher compression gains, error robustness, and network/device adaptability are described and discussed.
Data compression method for real-world haptic using DCT
- H Tanaka
- K Ohnishi