Index Fingertip Research Articles

An Optimization Approach to Teleoperation of the Thumb of a Humanoid Robot Hand: Kinematic Mapping and Calibration

The complex kinematic structure of a human thumb makes it difficult to capture and control the thumb motions. A further complication is that mapping the fingertip position alone leads to inadequate grasping postures for current robotic hands, many of which are equipped with tactile sensors on the volar side of the fingers. This paper aimed to use a data glove as the input device to teleoperate the thumb of a humanoid robotic hand. An experiment protocol was developed with only minimum hardware involved to compensate for the differences in kinematic structures between a robotic hand and a human hand. A nonlinear constrained-optimization formulation was proposed to map and calibrate the motion of a human thumb to that of a robotic thumb by minimizing the maximum errors (minimax algorithms) of fingertip position while subject to the constraint of the normals of the surfaces of the thumb and the index fingertips within a friction cone. The proposed approach could be extended to other teleoperation applications, where the master and slave devices differ in kinematic structure.

Disulfide Bond Requirements for Active Wnt Ligands

Secreted Wnt lipoproteins are cysteine-rich and lipid-modified morphogens that bind to the Frizzled (FZD) receptor and LDL receptor-related protein 6 (LRP6). Wnt engages FZD through protruding thumb and index finger domains, which are each assembled from paired β strands secured by disulfide bonds and grasp two sides of the FZD ectodomain. The importance of Wnt disulfide bonds has been assumed but uncharacterized. We systematically analyzed cysteines and associated disulfide bonds in the prototypic Wnt3a. Our data show that mutation of any individual cysteine of Wnt3a results in covalent Wnt oligomers through ectopic intermolecular disulfide bond formation and diminishes/abolishes Wnt signaling. Although individual cysteine mutations in the amino part of the saposin-like domain and in the base of the index finger are better tolerated and permit residual Wnt3a secretion/activity, those in the amino terminus, the thumb, and at the tip of the index finger are incompatible with secretion and/or activity. A few select double cysteine mutants based on the disulfide bond pattern restore Wnt secretion/activity. Further, a double cysteine mutation at the index finger tip results in a Wnt3a with normal secretion but minimal FZD binding and dominant negative properties. Our results experimentally validate predictions from the Wnt crystal structure and highlight critical but different roles of the saposin-like and cytokine-like domains, including the thumb and the index finger in Wnt folding/secretion and FZD binding. Finally, we modified existing expression vectors for 19 epitope-tagged human WNT proteins by removal of a tag-supplied ectopic cysteine, thereby generating tagged WNT ligands active in canonical and non-canonical signaling.

Capillary refill time exploration during septic shock.

During septic shock management, the evaluation of microvascular perfusion by skin analysis is of interest. We aimed to study the skin capillary refill time (CRT) in a selected septic shock population. We conducted a prospective observational study in a tertiary teaching hospital. After a preliminary study to calculate CRT reproducibility, all consecutive patients with septic shock during a 10-month period were included. After initial resuscitation at 6 h (H6), we recorded hemodynamic parameters and analyzed their predictive value on 14-day mortality. CRT was measured on the index finger tip and on the knee area. CRT was highly reproducible with an excellent inter-rater concordance calculated at 80% [73-86] for index CRT and 95% [93-98] for knee CRT. A total of 59 patients were included, SOFA score was 10 [7-14], SAPS II was 61 [50-78] and 14-day mortality rate was 36%. CRT measured at both sites was significantly higher in non-survivors compared to survivors (respectively 5.6 ± 3.5 vs 2.3 ± 1.8 s, P < 0.0001 for index CRT and 7.6 ± 4.6 vs 2.9 ± 1.7 s, P < 0.0001 for knee CRT). The CRT at H6 was strongly predictive of 14-day mortality as the area under the curve was 84% [75-94] for the index measurement and was 90% [83-98] for the knee area. A threshold of index CRT at 2.4 s predicted 14-day outcome with a sensitivity of 82% (95% CI [60-95]) and a specificity of 73% (95% CI [56-86]). A threshold of knee CRT at 4.9 s predicted 14-day outcome with a sensitivity of 82% (95% CI [60-95]) and a specificity of 84% (95% CI [68-94]). CRT was significantly related to tissue perfusion parameters such as arterial lactate level and SOFA score. Finally, CRT changes during shock resuscitation were significantly associated with prognosis. CRT is a clinical reproducible parameter when measured on the index finger tip or the knee area. After initial resuscitation of septic shock, CRT is a strong predictive factor of 14-day mortality.

Intra- and inter-hemispheric effective connectivity in the human somatosensory cortex during pressure stimulation

BackgroundSlow-adapting type I (SA-I) afferents deliver sensory signals to the somatosensory cortex during low-frequency (or static) mechanical stimulation. It has been reported that the somatosensory projection from SA-I afferents is effective and reliable for object grasping and manipulation. Despite a large number of neuroimaging studies on cortical activation responding to tactile stimuli mediated by SA-I afferents, how sensory information of such tactile stimuli flows over the somatosensory cortex remains poorly understood. In this study, we investigated tactile information processing of pressure stimuli between the primary (SI) and secondary (SII) somatosensory cortices by measuring effective connectivity using dynamic causal modeling (DCM). We applied pressure stimuli for 3 s to the right index fingertip of healthy participants and acquired functional magnetic resonance imaging (fMRI) data using a 3T MRI system.ResultsDCM analysis revealed intra-hemispheric effective connectivity between the contralateral SI (cSI) and SII (cSII) characterized by both parallel (signal inputs to both cSI and cSII) and serial (signal transmission from cSI to cSII) pathways during pressure stimulation. DCM analysis also revealed inter-hemispheric effective connectivity among cSI, cSII, and the ipsilateral SII (iSII) characterized by serial (from cSI to cSII) and SII-level (from cSII to iSII) pathways during pressure stimulation.ConclusionsOur results support a hierarchical somatosensory network that underlies processing of low-frequency tactile information. The network consists of parallel inputs to both cSI and cSII (intra-hemispheric), followed by serial pathways from cSI to cSII (intra-hemispheric) and from cSII to iSII (inter-hemispheric). Importantly, our results suggest that both serial and parallel processing take place in tactile information processing of static mechanical stimuli as well as highlighting the contribution of callosal transfer to bilateral neuronal interactions in SII.

Hierarchical predictive system for the neural integration of incoming somatosensory stimulations

Hierarchical predictive system for the neural integration of incoming somatosensory stimulations

Within, but not between hands interactions in vibrotactile detection thresholds reflect somatosensory receptive field organization

Detection of a tactile stimulus on one finger is impaired when a concurrent stimulus (masker) is presented on an additional finger of the same or the opposite hand. This phenomenon is known to be finger-specific at the within-hand level. However, whether this specificity is also maintained at the between hand level is not known. In four experiments, we addressed this issue by combining a Bayesian adaptive staircase procedure quick estimation of threshold (QUEST) with a two-interval forced choice (2IFC) design in order to establish threshold for detecting 200 ms, 100 Hz sinusoidal vibrations applied to the index or little fingertip of either hand (targets). We systematically varied the masker finger (index, middle, ring, or little finger of either hand), while controlling the spatial location of the target and masker stimuli. Detection thresholds varied consistently as a function of the masker finger when the latter was on the same hand (Experiments 1 and 2), but not when on different hands (Experiments 3 and 4). Within the hand, detection thresholds increased for masker fingers closest to the target finger (i.e., middle > ring when the target was index). Between the hands, detection thresholds were higher only when the masker was present on any finger as compared to when the target was presented in isolation. The within hand effect of masker finger is consistent with the segregation of different fingers at the early stages of somatosensory processing, from the periphery to the primary somatosensory cortex (SI). We propose that detection is finger-specific and reflects the organization of somatosensory receptive fields in SI within, but not between the hands.

Physical Factors Influencing Pleasant Touch during Tactile Exploration

BackgroundWhen scanning surfaces, humans perceive some of their physical attributes. These percepts are frequently accompanied by a sensation of (un)pleasantness. We therefore hypothesized that aspects of the mechanical activity induced by scanning surfaces with fingertips could be objectively associated with a pleasantness sensation. Previously, we developed a unidimensional measure of pleasantness, the Pleasant Touch Scale, quantifying the pleasantness level of 37 different materials. Findings of this study suggested that the sensation of pleasantness was influenced by the average magnitude of the frictional forces brought about by sliding the finger on the surface, and by the surface topography. In the present study, we correlated (i) characteristics of the fluctuations of frictional forces resulting from the interaction between the finger and the surface asperities as well as (ii) the average friction with the sensation of pleasantness.ResultsEight blindfolded participants tactually explored twelve materials of the Pleasant Touch Scale through lateral sliding movements of their index fingertip. During exploration, the normal and tangential interaction force components, fN and fT, as well as the fingertip trajectory were measured. The effect of the frictional force on pleasantness sensation was investigated through the analysis of the ratio fT to fN, i.e. the net coefficient of kinetic friction, μ. The influence of the surface topographies was investigated through analysis of rapid fT fluctuations in the spatial frequency domain. Results showed that high values of μ were anticorrelated with pleasantness. Furthermore, surfaces associated with fluctuations of fT having higher amplitudes in the low frequency range than in the high one were judged to be less pleasant than the surfaces yielding evenly distributed amplitudes throughout the whole spatial frequency domain.ConclusionCharacteristics of the frictional force fluctuations and of the net friction taking place during scanning can reliably be correlated with the pleasantness sensation of surfaces.

Parkinson’s disease patients show impaired corrective grasp control and eye–hand coupling when reaching to grasp virtual objects

The effect of Parkinson’s disease (PD) on hand–eye coordination and corrective response control during reach-to-grasp tasks remains unclear. Moderately impaired PD patients (n=9) and age-matched controls (n=12) reached to and grasped a virtual rectangular object, with haptic feedback provided to the thumb and index fingertip by two 3-degree of freedom manipulanda. The object rotated unexpectedly on a minority of trials, requiring subjects to adjust their grasp aperture. On half the trials, visual feedback of finger positions disappeared during the initial phase of the reach, when feedforward mechanisms are known to guide movement. PD patients were tested without (OFF) and with (ON) medication to investigate the effects of dopamine depletion and repletion on eye–hand coordination online corrective response control. We quantified eye–hand coordination by monitoring hand kinematics and eye position during the reach. We hypothesized that if the basal ganglia are important for eye–hand coordination and online corrections to object perturbations, then PD patients tested OFF medication would show reduced eye–hand spans and impoverished arm-hand coordination responses to the perturbation, which would be further exasperated when visual feedback of the hand was removed. Strikingly, PD patients tracked their hands with their gaze, and their movements became destabilized when having to make online corrective responses to object perturbations exhibiting pauses and changes in movement direction. These impairments largely remained even when tested in the ON state, despite significant improvement on the Unified Parkinson’s Disease Rating Scale. Our findings suggest that basal ganglia-cortical loops are essential for mediating eye–hand coordination and adaptive online responses for reach-to-grasp movements, and that restoration of tonic levels of dopamine may not be adequate to remediate this coordinative nature of basal ganglia-modulated function.

Effect of the number of pins and inter-pin distance on somatosensory evoked magnetic fields following mechanical tactile stimulation

Magnetoencephalography (MEG) recordings were collected to investigate the effect of the number of mechanical pins and inter-pin distance on somatosensory evoked magnetic fields (SEFs) following mechanical stimulation (MS). We used a 306-ch whole-head MEG system. SEFs were elicited through tactile stimuli with 1-, 2-, 3-, 4- and 8-pins using healthy participants. Tactile stimuli were applied to the tip of the right index finger. SEF following electrical stimulation of the index finger was recorded in order to compare the activity in the primary somatosensory cortex (S1) following MS. Prominent SEFs were recorded from the contralateral hemisphere approximately 54ms (P50m) and 125ms (P100m) after MS regardless of the number of pins. Equivalent current dipoles were located in the S1. The source activities for P50m and P100m significantly increased in tandem with the number of pins for MS. However, the increased ratios for the source activities according to the increase in the number of pins were significantly smaller than that induced by electrical stimulation, and when the number of the pins doubled from 1-pin to 2-pins, from 2-pins to 4-pins, and from 4-pins to 8-pins, S1 activities increased by only 130%. Additionally, source activities significantly increased when the inter-pin distance increased from 2.4 to 7.2mm. The number of stimulated receptors was considered to have increased with an increase in the inter-pin distance as well as an increase in the number of pins. These findings clarified the effect of the number of pins and inter-pin distance for MS on SEFs.

Design evaluation of information appliances using augmented reality-based tangible interaction

In this paper, we propose an approach to tangible augmented reality (AR) based design evaluation of information appliances, which not only exploits the use of tangible objects without hardwired connections to provide better visual immersion and support more tangible interaction, but also facilitates the adoption of a simple and low cost AR environment setup to improve user experience and performance. To enhance the visual immersion, we develop a solution for resolving hand occlusion in which skin color information is exploited with the use of the tangible objects to detect the hand regions properly. To improve the tangible interaction with the sense of touch, we introduce the use of product- and fixture-type objects, which provides the feelings of holding the product in his or her hands and touching buttons with his or her index fingertip in the AR setup. To improve user experience and performance in view of hardware configuration, we devise to adopt a simple and cost-effective AR setup that properly meets guidelines such as viewing size and distance, working posture, viewpoint matching, and camera movement. From experimental results, we found that the AR setup is good to improve the user experience and performance in design evaluation of handheld information appliances. We also found that the tangible interaction combined with the hand occlusion solver in the AR setup is very useful to improve tangible interaction and immersive visualization of virtual products while making the user experience the shapes and functions of the products well and comfortably.

Uso da informação somatossensorial adicional no controle postural: efeito da dominância manual

Buscamos com o presente estudo investigar o efeito da dominância manual e da visão no uso da informação somatossensorial adicional fornecida pelo toque suave no controle postural. Quinze adultos jovens e destros permaneceram em pé sobre uma plataforma de força com a) olhos abertos ou fechados e b) braços ao lado do corpo ou o dedo indicador direito ou esquerdo tocando a barra fixa. A área do centro de pressão (CP), amplitude e velocidade médias do CP nas direções anteroposterior e médio-lateral foram avaliadas. Os resultados indicaram uma redução nas medidas nas condições de toque e aumento com os olhos fechados, exceto quando o toque foi realizado com dedo indicador direito. A força máxima foi maior para a mão direita, enquanto a sensibilidade cutânea e as forças aplicadas à barra foram similares entre os hemicorpos. Esses resultados sugerem um efeito da dominância manual e visão no uso da informação somatossensorial adicional no controle postural.

Continuous Theta Burst Stimulation of the Supplementary Motor Area: Effect Upon Perception and Somatosensory and Motor Evoked Potentials

BackgroundThe supplementary motor area (SMA) has been implicated in many aspects of movement preparation and execution. In addition to motor roles, the SMA is responsive to somesthetic stimuli though it is unclear exactly what role the SMA plays in a somatosensory network. Objective/HypothesisIt is the purpose of this study to assess how continuous theta burst stimulation (cTBS) of the SMA affects both somatosensory (SEPs) and motor evoked potentials (MEPs) and if cTBS leads to alterations in tactile perception thresholds of the index fingertip. MethodsIn experiment 1, cTBS was delivered over scalp sites FCZ (SMA stimulation) (n = 10) and CZ (control stimulation) (n = 10) in separate groups for 40 s (600 pulses) at 90% of participants' resting motor threshold. For both groups, median nerve SEPs were elicited from the right wrist at rest via electrical stimulation (0.5 ms pulse) before and at 10 min intervals post-cTBS out to 30 min (t = pre, 10, 20, and 30 min). Subjects' perceptual thresholds were assessed at similar time intervals as the SEP data using a biothesiometer (120 Hz vibration). In experiment 2 (n = 10) the effect of cTBS to SMA upon single and paired-pulse MEP amplitudes from the right first dorsal interosseous (FDI) was assessed. ResultscTBS to scalp site FCZ (SMA stimulation) reduced the frontal N30 SEP and increased tactile perceptual thresholds 30 min post-stimulation. However, parietal SEPs and MEP amplitudes from both single and paired-pulse stimulation were unaffected at all time points post-stimulation. cTBS to stimulation site CZ (control) did not result in any physiological or behavioral changes. Conclusion(s)These data demonstrate cTBS to the SMA reduces the amplitude of the N30 coincident with an increase in vibration sensation threshold but does not affect primary somatosensory or motor cortex excitability. The SMA may play a significant role in a somatosensory tactile attention network.

Predictive mechanisms in the control of contour following

In haptic exploration, when running a fingertip along a surface, the control system may attempt to anticipate upcoming changes in curvature in order to maintain a consistent level of contact force. Such predictive mechanisms are well known in the visual system, but have yet to be studied in the somatosensory system. Thus, the present experiment was designed to reveal human capabilities for different types of haptic prediction. A robot arm with a large 3D workspace was attached to the index fingertip and was programmed to produce virtual surfaces with curvatures that varied within and across trials. With eyes closed, subjects moved the fingertip around elliptical hoops with flattened regions or Limaçon shapes, where the curvature varied continuously. Subjects anticipated the corner of the flattened region rather poorly, but for the Limaçon shapes, they varied finger speed with upcoming curvature according to the two-thirds power law. Furthermore, although the Limaçon shapes were randomly presented in various 3D orientations, modulation of contact force also indicated good anticipation of upcoming changes in curvature. The results demonstrate that it is difficult to haptically anticipate the spatial location of an abrupt change in curvature, but smooth changes in curvature may be facilitated by anticipatory predictions.

Limited Persistence of Tactile Working Memory Resources During Delay- Dependent Grating Orientation Discrimination

Working memory is a system that actively holds information to make it available for further processing. Compared to the working memory associated with vision and audition, the human characteristics of tactile working memory are largely unknown. In this study, we collected behavioral evidence of delay-dependent tactile grating orientation discrimination in humans. Nine healthy subjects participated in the experiment. During each trial, two of seven tactile grating domes of either similar or different orientation were presented to the subject’s right index fingertip. The interstimulus delays used in the experiment were 1, 5, 10, 15, 20, 25 and 30 seconds. The subjects were asked to discriminate whether the two orientations were the same. We found that the performance of tactile orientation discrimination improved with larger differences between the presented stimulus orientations. We also found a same/different effect, in which the accuracy and reaction time (RT) resulting from the same-orientation discrimination condition differed from that of the differentorientation discrimination condition. Interestingly, the existence of delay dependence was found under the sameorientation discrimination condition, in which the performance was reduced as the delay time was increased. However, we did not find delay dependence in the different-orientation discrimination condition. These findings of non-identical tactile stimulus discrimination can be understood in the context of tactile memory processing. Keywords: Decision making, delay, passive touch, somatosensory, tactile orientation discrimination, working memory.

Forearm–finger skin temperature gradient as an index of cutaneous perfusion during steady‐state exercise

The purpose of this study was to examine whether the forearm-finger skin temperature gradient (T(forearm-finger)), an index of vasomotor tone during resting conditions, can also be used during steady-state exercise. Twelve healthy men performed three cycling trials at an intensity of ~60% of their maximal oxygen uptake for 75 min separated by at least 48 h. During exercise, forearm skin blood flow (BFF ) was measured with a laser-Doppler flowmeter, and finger skin blood flow (PPG) was recorded from the left index fingertip using a pulse plethysmogram. T(forearm-finger) of the left arm was calculated from the values derived by two thermistors placed on the radial side of the forearm and on the tip of the middle finger. During exercise, PPG and BFF increased (P<0.001), and T(forearm-finger) decreased (P<0.001) from their resting values, indicating a peripheral vasodilatation. There was a significant correlation between T(forearm-finger) and both PPG (r = -0.68; P<0.001) and BFF (r = -0.50; P<0.001). It is concluded that T(forearm-finger) is a valid qualitative index of cutaneous vasomotor tone during steady-state exercise.

Evaluation of the VPT‐60 to measure peripheral nerve sensitivity

The loss of peripheral nerve sensitivity can result in serious morbidity (including limb amputation) and mortality. Monitoring peripheral nerve sensitivity is important in avoiding these consequences.The purpose of this study was to evaluate the capability of an experimental VPT‐60 to accurately determine peripheral nerve sensitivity. Peripheral nerve sensitivity measurements from the VPT‐60 were compared to measurements of the two clinical reference standards, Semmes‐Weinstein monofilaments (SWM) and the Bio‐Thesiometer (BT).Peripheral nerve sensitivity and temperature of the index finger tip of 41 subjects, with ages ranging from 20–87 years, and mean SWM size range of 2.4–4.2 were measured. Finger tip temperature ranged from 71.4–88.2°F, and the force exerted by the finger on the vibrating probe ranged from &lt;1.0 to 82 grams. Each subject's nerve sensitivity was measured 3 times with each of the 3 instruments.The correlation coefficient (r) of VPT‐60 and SWM was 0.75 and between the VPT‐60 and the BT was 0.86. The r between SWM and BT was only 0.51. As the nerve sensitivity decreased, the sensitivity of the VPT‐60 to detect changes increased. Reliability of the VPT‐60, SWM, and BT was 0.88, 0.78, and 0.74 respectively. In conclusion, this study indicates that the VPT‐60 provides results that are as capable as, if not more capable than, the gold standards in determining peripheral nerve sensitivity.

Accuracy of pointing movements relies upon a specific tuning between anticipatory postural adjustments and prime mover activation

Equilibrium-perturbing forces associated with a voluntary upper-limb movement can be strong enough to displace the whole-body centre of mass. In this condition, anticipatory postural adjustments (APAs), developing in muscles other than the prime mover, are essential in maintaining the whole-body balance. Here, we test the hypothesis that APAs preceding an upper-limb target-reaching movement could play a role also in controlling the movement accuracy. Standing subjects (10) were asked to flex the right shoulder and touch with the index fingertip the centre of a target positioned in front of them. The reaching task was also performed while wearing and after doffing prismatic lenses (shifting the eye field rightward). EMGs from different upper- and lower-limb muscles and the mechanical actions to the ground were recorded. (i) Before wearing prisms, subjects were very accurate in hitting the target, and the pointing movements were accompanied by APAs in quadriceps (Q) and tibialis anterior (TA) of both sides, and in right hamstrings (H) and soleus (SOL). (ii) After donning prisms, rightward pointing errors occurred, associated with a significant APA increase in right Q and TA, but without changes in the recruitment of right anterior deltoid (prime mover) and biceps brachii. (iii) These pointing errors were progressively compensated in about 10 trials, indicating a sensorimotor adaptation, and APAs returned to values recorded before wearing prisms. (iv) After doffing prisms, pointing errors occurred in the opposite direction but changes in APAs did not reach significance. We propose that, besides preserving the whole-body balance, APAs are also tailored to obtain an accurate voluntary movement.

Edward Hallarran Bennett: Bennett's Fracture of the Base of the Thumb

Bennett's fracture involves part of the base of the metacarpal bone of the thumb. The fracture line runs obliquely and involves the joint between the first metacarpal and the adjacent carpal bone--the trapezium. The shaft of the metacarpal is pulled proximally by the action of the long muscles attached to the thumb, so a fracture-dislocation of the thumb carpo-metacarpal joint results. The injury occurs typically in young men as a result of a blow on the clenched fist, either in a fall or, very often, in landing a blow in boxing. Now this joint happens to be of extreme importance in fine movements of the thumb, because it is here that opposition of the thumb takes place. Look at your own hand; now put the tip of your thumb onto the tip of your index finger; this is opposition and only man and monkeys can carry out this action. It is this important movement that you use when writing, when holding a scissors or a scalpel. When you look at the two bones articulating together they resemble someone sitting on a saddle and the joint, the only one of its kind in your limbs, is appropriately called a 'saddle joint'.

A Resected Melanoma of the Lung Metastasized from an Occult Skin Lesion: A Case Report

An 86-year-old woman with a history of right breast cancer resected seven years ago had a small pulmonary nodule located in left S5. Diagnosis was made by bronchoscopy using the endobronchial ultrasonography-guided sheath (EBUS-GS) method, but a histological diagnosis was not obtained. Wedge resection was performed due to suspicion of a metastatic lesion from breast cancer based on radiological findings. The tumor was subsequently found to be malignant melanoma of the lung. An initial diagnosis of primary melanoma of the lung was made because a melanoma lesion at another site was not seen despite a detailed work up. However, 8 months after surgery, a malignant melanoma appeared at the tip of the right index finger. We rediagnosed the lung lesion as a metastatic malignant melanoma based on the low incidence of primary melanoma of the lung and on the pathological features.

주시안과 검지 끝 점을 이용한 3차원 물리 사용자 인터페이스 시스템

In this paper, we propose a new 3D PUI(Physical User Interface) system in which the index fingertip points and moves a mouse position on a given monitor screen. There are two 3D PUI schemes to control smart devices like smart TVs remotely, the relative pointing one and the absolute pointing one. The former has a problem in that it does not match the human perception process, and the latter requires excessive movement of the body. We combined the relative one and the absolute one, and develop a new intuitive and user-friendly pointing method, 3D PUI. It requires an establishment of a pyramid shape visible area (view volume) to point a mouse position on a screen with the dominant eye. In order to maintain the real-time view volume, however, it requires large computation depending on the movement of the dominant eye. We optimized the computation of the view volume in which it determines the internal and external position on the screen. In addition, Kalman filter is applied with tracing of the mouse pointer position to stabilize the trembling of the pointer and offers the user ease of use.