Accuracy Of Target Selection Research Articles

Time to Capture a Moving Target Travelling along a Circular Trajectory

This study measured the time it took to select a target moving along a circular trajectory with a computer mouse. The time was changed according to the speed of the target, the width of target and the distance from the starting point to the target. However, the effect of these independent variables on the dependent variable was different from what was expected. In the previous studies, it was assumed that the faster the moving target speed, the longer the target selection time, because increased target speed had the effect of narrowing the effective target width. However, as a result of the experiment, the target selection time was rather shortened when the moving speed of the target was increased. This may be because the subjects intend to speed up target selection while decreasing the accuracy of target selection in order to adapt to a fast-moving target. The modified Fitts’ model for the moving target selection time proposed in a previous study did not take these user responses into account. A more modified model is required to more accurately describe the selection time of moving target.

Touchless Head-Control (THC): Head Gesture Recognition for Cursor and Orientation Control.

The touchless techniques in human-computer interaction (HCI) can effectively expand computer access capabilities for disabled people. This paper presents Touchless Head-Control (THC), an assistive system method for computer cursor control based on head pose captured with an RGB camera. Our work aimed to replace the standard cursor control using a device on the user's head. The convolutional neural networks with predicted fine-grained feature maps and binned classification were applied to estimate the head pose angles. The mouse pointer or cursor is moved to actual locations on the screen based on head movement (yaw and pitch) and the center position of the face. Head tilt to the right or left (roll) to control the mouse button. In addition, the proposed method can be used to simulate the movement of the robot or joystick using the head to control objects within three degrees of freedom (DOF). Various participants were involved in the interaction design evaluation, in which target selection accuracy, travel time, and path efficiency were measured. This technology allows people with limited motor skills to easily control a PC cursor and 3D object orientation without the use of additional equipment or sensors.

Mouse on a Ring: A Mouse Action Scheme Based on IMU and Multi-Level Decision Algorithm

The traditional mouse has been used as a main tool for human-computer interaction for more than 50 years. However, it has become unable to cater to people’s need for mobile officing and all-weather use due to its reliance on the support of a two-dimensional plane, poor portability, wearisomeness, and other problems. In this paper, we propose a portable ring-type wireless mouse scheme based on IMU sensors and a multi-level decision algorithm. The user only needs to operate in the air with a smart ring worn on the middle finger of their right hand to realize the interactive function of a mouse. The smart ring first captures changes in the finger’s attitude angle to reflect how the cursor position changes. And, it captures the rapid rotation of the user’s palm to the left and right to achieve mouse clicking. In addition, a multi-level decision algorithm is developed to improve the response speed and recognition accuracy of the virtual mouse. The experimental results show that the virtual mouse has a target selection accuracy of over 96%, which proves its practicability in real-world applications. This virtual mouse is expected to be used as a portable and reliable tool for multi-scenario human-computer interaction applications in the future.

BayesGaze: A Bayesian Approach to Eye-Gaze Based Target Selection.

Selecting targets accurately and quickly with eye-gaze input remains an open research question. In this paper, we introduce BayesGaze, a Bayesian approach of determining the selected target given an eye-gaze trajectory. This approach views each sampling point in an eye-gaze trajectory as a signal for selecting a target. It then uses the Bayes' theorem to calculate the posterior probability of selecting a target given a sampling point, and accumulates the posterior probabilities weighted by sampling interval to determine the selected target. The selection results are fed back to update the prior distribution of targets, which is modeled by a categorical distribution. Our investigation shows that BayesGaze improves target selection accuracy and speed over a dwell-based selection method, and the Center of Gravity Mapping (CM) method. Our research shows that both accumulating posterior and incorporating the prior are effective in improving the performance of eye-gaze based target selection.

Effects of fatigue on steady state motion visual evoked potentials: Optimised stimulus parameters for a zoom motion-based brain-computer interface

Background and ObjectiveIn flicker-based steady-state visual evoked potentials (SSVEP) brain-computer interface (BCI), the system performance decreases due to prolonged repeated visual stimulation. To reduce the performance decrease due to visual fatigue, the zoom motion based steady-state motion visual evoked potentials (SSMVEPs) paradigm had been proposed. In this study, the stimulation parameters of the paradigm are optimised to mitigate the decrease in detection accuracy for SSMVEP due to visual fatigue. MethodsEight zoom motion-based SSMVEP paradigms with different stimulation parameters were compared. The graph size, luminance, colour, and shape, as well as the frequency range and interval of the stimulation and refresh rate of the screen was changed to determine the optimal paradigm with high recognition accuracy and reduced fatigue effects. The signal-to-noise ratio (SNR) of SSMVEP was also calculated for four fatigue levels. Moreover, the power spectral density of electroencephalograph (EEG) alpha and theta bands during ongoing activity was calculated for the stimulation experiment to evaluate fatigue at the start and end of the stimulation task. ResultsAll stimulation SSMVEP paradigms exhibited high accuracies. Changes in luminance, colour, and shape did not impact the recognition accuracy, nor did a higher stimulation frequency or lower frequency interval of each stimulation block. However, the paradigm with smaller stimulus achieved the highest average target selection accuracy of 97.2%, compared to 94.9% for the standard paradigm. Furthermore, it exhibited almost zero reduction in recognition accuracy due to fatigue. From fatigue level 1 to level 4, the smaller zoom motion-based SSMVEP exhibited a lower decrease in the SNR of SSMVEP and a lower alpha/theta ratio decrease during ongoing stimulation activity compared to the standard paradigm. ConclusionsFor a zoom motion-based SSMVEP paradigm, changing multiple stimulation parameters can lead to the same high performance as the standard paradigm. Moreover, using a smaller stimulus can reduce the accuracy decrease caused by fatigue because the SNR decrease in the evoked SSMVEP state was negligible and the alpha/theta index decrease during ongoing activity was lower than that for the standard paradigm.

Strategy for Improving Target Selection Accuracy in Indirect Touch Input

Strategy for Improving Target Selection Accuracy in Indirect Touch Input

Cursor Click Modality in an Accelerometer-Based Computer Access Device

The purpose of this study is to investigate the effects of different cursor click modalities in an alternative computer access device using accelerometry from head tilt to control cursor movement. Eighteen healthy adults performed a target acquisition task using the device with five different cursor click modalities, while maintaining cursor movement control via accelerometry. Three dwell-based click modalities with dwell times of 0.5 s, 1.0 s, and 1.5 s were tested. Two surface electromyography-based click modalities - with the sensor placed next to the eye for a blink and above the eyebrow for a brow raise - were tested. Performance was evaluated using metrics of target selection accuracy, path efficiency, target selection time, and user effort. Surface electromyography-based click modalities were as fast as the shortest dwell time and as accurate as the longest dwell time, and also minimized user effort. Three of the four performance metrics were not affected by sensor location. Future studies will investigate if these results are similar in individuals with neuromuscular disorders.

Integrated Head-Tilt and Electromyographic Cursor Control.

This study evaluated the performance of two alternate computer access methods that could be used for two-dimensional cursor control. The first method, ACC/sEMG, integrates head acceleration and facial surface electromyography. The second method, Camera Mouse, is a free-to-use, computer vision-based access method. Twenty-four healthy adults performed a target acquisition task using each computer access method across two lighting conditions and three computer orientations. Performance in the task was evaluated using metrics of target selection accuracy, movement time, and path efficiency. Using ACC/sEMG resulted in better mean path efficiency and target selection accuracy, whereas using Camera Mouse resulted in faster target selection. Moreover, performance in the task when using Camera Mouse depended on lighting conditions in the room. The findings of this study show that the ACC/sEMG system is an effective computer access method across different lighting conditions and computer orientations. However, there is a tradeoff between speed and accuracy: ACC/sEMG system provided higher target selection accuracy compared to Camera Mouse, while the latter provided faster target selection. Future development should focus on evaluating performance of each method in populations with limited motor abilities.

The Study of Two Novel Speech-Based Selection Techniques in Voice-User Interfaces

The voice-based technology is a promising alternative input modality to the conventional computer input devices, such as keyboards and mice. For mobility-impaired people who cannot use the traditional computer input devices, a voice-based interactive solution is highly desirable. Although some grid-based cursor control systems that use speech recognition show potentials, they come with limitations in processing time and difficulties in real-time applications. Since they are not natural enough to use, it is very slow to drill down the grid, and the point cursor selection range is prone to errors, and people need a more efficient and natural choice. To address these limitations, this paper proposes two novel speech-based target selection techniques: grid-based region selection (hereinafter referred to as “Region Selection”) and grid-based target search (hereinafter referred to as “Target Search”). Region Selection allows users to select targets directly using the selected area. Target Search permits users to move the cursor to a target in a specified direction. Experiments are designed and conducted to analyze the impacts of target size and target density on performance and processing time. The experimental results and comparison study with traditional solution show that both Region Selection and Target Search improve the participants’ accuracy of target selection and reduce the processing time, especially for small targets.

A hybrid BCI-controlled smart home system combining SSVEP and EMG for individuals with paralysis

In this study, electromyogram (EMG) signals associated with occlusal movement were integrated with steady-state visual evoked potentials (SSVEPs) to develop a hybrid brain–computer interface (hBCI)-based smart home control system for individuals with paralysis. The SSVEP paradigm was used to develop a system containing one main interface and five sub-interfaces corresponding to several devices during the working state, and one interface for the idle state. Participants controlled the devices by gazing at certain stimuli, which flickered at different frequencies for each function. Classical correlation analysis (CCA) of four channel EEG signals was used to recognize SSVEP features as intended selection. Several particular occlusal EMG patterns from the single channel of temporalis muscle were used to confirm the selected function, return from the sub-interface to the main interface, and switch the system on/off, respectively. Five healthy participants and five individuals with paralysis completed the system control experiment. The average target selection accuracy reached 97.5% and 83.6% in healthy participants and patients, while the confirmation accuracy in each group reached 97.6% and 96.9%, respectively. When SSVEPs were combined with EMG signals from occlusal movement to confirm the target selection, the actual control accuracy was maximized to 100%, and the information transmission rate (ITR) reached 45 bit/min among patients. Operation of the hBCI-based smart home control system did not cause higher mental or physical workload in patients compared to healthy participants. Our findings indicate that combining SSVEP and EMG signals effectively enhances the safety and interactivity of hBCI-based smart home systems.

Application of MRS- and ASL-guided navigation for biopsy of intracranial tumors.

The diagnosis of a tumor depends on accurate identification of the target area for biopsy. However, tumor heterogeneity and the inability of conventional structural data for identifying the most malignant areas can reduce this accuracy. To evaluate the feasibility and practicality of magnetic resonance spectroscopy (MRS)- and arterial spin labeling (ASL)-guided MRI navigation for needle biopsy of intracranial tumors. Thirty patients with intracranial tumors who underwent intraoperative stereotactic biopsy were retrospectively analyzed. Contrast-enhanced 3D-BRAVO or 3D-T2FLAIR structural data, combined with MRS and ASL data, were used to identify the target area for biopsy. High-choline or high-perfusion sites were chosen preferentially, and then the puncture trajectory was optimized to obtain specimens for histopathologic examination. Twenty-two specimens were collected from 20 glioma patients (two specimens each were collected from two patients) and ten specimens were collected from ten lymphoma patients. The diagnosis rate after the biopsy was 93.3% (28/30). Two gliomas were initially diagnosed as gliosis and subsequently diagnosed correctly after the collection of a second biopsy specimen. Combined MRS and ASL helped target selection in 23 cases (76.7%), including three cases each of low-enhancing and non-enhancing gliomas. In two cases, the target selection decision was changed because the areas initially chosen on the basis of positron emission tomography data did not match the high-perfusion areas identified with ASL. Compared with conventional MRI, combined MRS and ASL improved the accuracy of target selection for the stereotactic biopsy of intracranial tumors.

Visual Stimuli for P300-Based Brain-Computer Interfaces: Color, Shape, and Mobility

The purpose of this study was to identify the impact of different discriminative features of stimuli in a P300 brain-computer interface paradigm on overall performance and evoked potentials. It has been shown that stimuli sets with a greater number of discriminative features yield better target selection accuracy. Target selection accuracy was significantly higher for the stimuli that differ from each other by color, shape, and semantics. Highest performance was achieved with the stimuli set containing the largest number of discriminative features, namely a set of nine different-colored letters. This result is mainly due to higher mean P300 peak amplitude for stimuli sets that contain more discriminative features. The results of the study can be used for designing a better user experience in brain-computer interfacing (BCI). Motion of the stimuli presentation point and characteristics of this motion (linear or pseudorandom) did not have any impact on BCI performance. This result is promising for future BCI designs with rapid serial visual presentation using mobile robots or augmented reality as stimuli presentation environment.

Fabrication of dielectrophoretic microfluidic chips using a facile screen-printing technique for microparticle trapping

Trapping of microparticles finds wide applications in numerous fields. Microfluidic chips based on a dielectrophoresis (DEP) technique hold several advantages for trapping microparticles, such as fast result processing, a small amount of sample required, high spatial resolution, and high accuracy of target selection. There is an unmet need to develop DEP microfluidic chips on different substrates for different applications in a low cost, facile, and rapid way. This study develops a new facile method based on a screen-printing technique for fabrication of electrodes of DEP chips on three types of substrates (i.e. polymethyl-methacrylate (PMMA), poly(ethylene terephthalate) and A4 paper). The fabricated PMMA-based DEP microfluidic chip was selected as an example and successfully used to trap and align polystyrene microparticles in a suspension and cardiac fibroblasts in a cell culture solution. The developed electrode fabrication method is compatible with different kinds of DEP substrates, which could expand the future application field of DEP microfluidic chips, including new forms of point-of care diagnostics and trapping circulating tumor cells.

Lesion of the isthmo-optic nucleus impairs target selection for visually guided reaching

Neurons in the isthmo-optic nucleus (ION) of the avian midbrain receive input predominantly from the ipsilateral optic tectum and project to the contralateral retina. Therefore, lesion in the ION removes tectal efferent signals to the retina in birds. In the present study, we trained Japanese quail to reach a target stimulus on a touch-sensor monitor with their beak. ION lesions significantly decreased response accuracy when the target was presented simultaneously with distractors but not when presented alone. Thus the removal of the tectal efferent signals to the retina severely impaired target selection in a competitive visual search as if the ION-lesioning caused visual extinction, which is a neuropsychological deficit seen in human hemispatial neglect patients. We suggest that the avian tectum and its efferent path to the retina improve the accuracy of target selection for visual orienting and visually guided reaching with beak.

Target Selection With Hybrid Feature for BCI-Based 2-D Cursor Control

To control a cursor on a monitor screen, a user generally needs to perform two tasks sequentially. The first task is to move the cursor to a target on the monitor screen (termed a 2-D cursor movement), and the second task is either to select a target of interest by clicking on it or to reject a target that is not of interest by not clicking on it. In a previous study, we implemented the former function in an EEG-based brain-computer interface system using motor imagery and the P300 potential to control the horizontal and vertical cursor movements, respectively. In this study, the target selection or rejection functionality is implemented using a hybrid feature from motor imagery and the P300 potential. Specifically, to select the target of interest, the user must focus his or her attention on a flashing button to evoke the P300 potential, while simultaneously maintaining an idle state of motor imagery. Otherwise, the user performs left-/right-hand motor imagery without paying attention to any buttons to reject the target. Our data analysis and online experimental results validate the effectiveness of our approach. The proposed hybrid feature is shown to be more effective than the use of either the motor imagery feature or the P300 feature alone. Eleven subjects attended our online experiment, in which a trial involved sequential 2-D cursor movement and target selection. The average duration of each trial and average accuracy of target selection were 18.19 s and 93.99% , respectively, and each target selection or rejection event was performed within 2 s.

The effects of platform motion and target orientation on the performance of trackball manipulation

The trackball has been widely employed as a control/command input device on moving vehicles, but few studies have explored the effects of platform motion on its manipulation. Fewer still have considered this issue in designing the user interface and the arrangement of console location and orientation simultaneously. This work describes an experiment carried out to investigate the performance of trackball users on a simple point-and-click task in a motion simulator. By varying the orientation of onscreen targets, the effect of cursor movement direction on performance is investigated. The results indicate that the platform motion and target orientation both significantly affect the time required to point and click, but not the accuracy of target selection. The movement times were considerably longer under rolling and pitching motions and for targets located along the diagonal axes of the interface. Subjective evaluations carried out by the participants agree with these objective results. These findings could be used to optimise console and graphical menu design for use on maritime vessels. Statement of Relevance: In military situations, matters of life or death may be decided in milliseconds. Any delay or error in classification and identification will thus affect the safety of the ship and its crew. This study demonstrates that performance of manipulating a trackball is affected by the platform motion and target orientation. The results of the present study can guide the arrangement of consoles and the design of trackball-based graphical user interfaces on maritime vessels.

Effect of Seated Position on Upper-Extremity Access to Augmentative Communication for Children With Cerebral Palsy: Preliminary Investigation

Our goal in this study was to determine the effect of seated position on upper-extremity access to augmentative communication for a child with cerebral palsy. A single-subject ABAB design was used with one 5-yr-old participant. We compared accuracy and speed of selection of targets on a speech-generating device in the participant's typical position and in an intervention position. The intervention position conformed to current clinical conventions and research on promoting upper-extremity movement. The intervention position was achieved through simple modifications to the participant's typical seating. Accuracy of target selection was moderately improved in the intervention position compared with the typical position. Results provide preliminary empirical evidence of the positive effects of functional seating on access to augmentative communication for children with cerebral palsy. Further research is required to confirm the positive effect of the intervention position across other people who use augmentative communication.

Considerations on using a lightpen-interactive system with young children

The lightpen is a simple interactive device allowing easy communication between a naive user and a computer. Very young children (4–6 years old) can use a lightpen interactively to pick out targets displayed on a VDU. Accuracy of target selection and stability of pointing with the lightpen was measured in these young children, and also in an older group of children (10–11 years old), who showed superior performance on both measures. In the younger group, both postural factors and physical fatigue sometimes affected lightpen handling. However, children of both age groups failed to compensate for parallax near the edges of the curved display screen. Recommendations are made for the programming and design of lightpen-interactive displays.