Showing papers on "Stylus published in 2017"

Non-contact on-machine measurement using a chromatic confocal probe for an ultra-precision turning machine

Abstract: On-machine measurement (OMM) involves the interruption of the machining process and the subsequent measurement of the workpiece without its removal from the machining tool. Chromatic confocal sensing is a well-known measurement technique that is able to evaluate the position of a point on an object surface along the optical axis of the system with high accuracy. The present study integrates a chromatic confocal measurement probe with an ultra-precision diamond turning machine to achieve the non-contact OMM of machined components. The procedure for establishing the position of the rotary axis of the spindle based on dual standard spheres is first described in detail, and the relevant OMM procedure for machined components of different surface topographies is explained. Then, a 50-μm quartz step height standard is employed to investigate the linear measurement accuracy of the chromatic confocal probe. Finally, the measurement accuracy of the proposed OMM method is compared experimentally with that of the stylus method. The results show that the estimated form error value of the OMM method agrees well with the value obtained by the stylus method. The proposed OMM method feasibly achieves non-contact OMM with a nanometer-level accuracy for an ultra-precision turning machine and is capable of reconstructing the 3D surface topography of flat, spherical, and aspheric surfaces. After integrating the OMM method, the ultra-precision turning machine can realize the function of processing-measurement integration.

DodecaPen: Accurate 6DoF Tracking of a Passive Stylus

Abstract: We propose a system for real-time six degrees of freedom (6DoF) tracking of a passive stylus that achieves sub-millimeter accuracy, which is suitable for writing or drawing in mixed reality applications. Our system is particularly easy to implement, requiring only a monocular camera, a 3D printed dodecahedron, and hand-glued binary square markers. The accuracy and performance we achieve are due to model-based tracking using a calibrated model and a combination of sparse pose estimation and dense alignment. We demonstrate the system performance in terms of speed and accuracy on a number of synthetic and real datasets, showing that it can be competitive with state-of-the-art multi-camera motion capture systems. We also demonstrate several applications of the technology ranging from 2D and 3D drawing in VR to general object manipulation and board games.

Ungrounded Haptic Augmented Reality System for Displaying Roughness and Friction

Abstract: This paper presents the design and validation of an ungrounded haptic augmented reality system that alters the roughness and friction of a rigid 3-D object. The user touches the object via a custom haptic stylus; the stylus tip is a ball mounted in a socket that has low internal friction and produces minimal vibrations, necessary conditions for creating a haptically clean interaction. We determine contact position and force using a six-axis force/torque sensor beneath the object. The object's apparent roughness and kinetic friction are altered using haptic models that we previously created from real tool-surface interaction data. The textural roughness model generates a vibration waveform in real time, which is played through a voice coil actuator. A solenoid inside the stylus applies a braking force to the ball for friction rendering. The friction model continually controls the solenoid current, setting the effective kinetic friction coefficient between the stylus tip and object surface to values between 0.20 and 0.52. Analysis of commanded and displayed haptic signals verifies that this system accurately overlays the modeled roughness and friction on the object's geometry, providing a significantly better match than the same models rendered using a Phantom Omni.

Non-Contact Surface Roughness Measurement by Implementation of a Spatial Light Modulator.

Abstract: The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.

FlexStylus: Leveraging Bend Input for Pen Interaction

Abstract: FlexStylus, a flexible stylus, detects deformation of the barrel as a vector with both a rotational and an absolute value, providing two degrees of freedom with the goal of improving the expressivity of digital art using a stylus device. We outline the construction of the prototype and the principles behind the sensing method, which uses a cluster of four fibre-optic based deformation sensors. We propose interaction techniques using the FlexStylus to improve menu navigation and tool selection. Finally, we describe a study comparing users' ability to match a changing target value using a commercial pressure stylus and the FlexStylus' absolute deformation. When using the FlexStylus, users had a significantly higher accuracy overall. This suggests that deformation may be a useful input method for future work considering stylus augmentation.

9.6 A 3.9kHz-frame-rate capacitive touch system with pressure/tilt angle expressions of active stylus using multiple-frequency driving method for 65″ 104×64 touch screen panel

Abstract: As the demand for interactive displays continues to increase, capacitive touch systems (CTSs) with stylus-based drawing have become indispensable [1–4]. Passive styli are widely used because of their low-cost implementation, but have low SNR and limited drawing expressions [1]. Active styli have gained interest to solve these problems [4]. The pressure of an active stylus can be expressed using a pressure-to-capacitance transducer [3,4], but the tilt angle has not been reported yet. In addition, analog front-end (AFE) ICs with high frame rates are in demand in response to the fast movements of finger and active styli. Conventional AFE ICs adopt a parallel driving method (PDM) to achieve high SNR, but suffer from low frame rates because the number of rows and columns of the driving matrix increases with the number of TX electrodes [3]. In this paper, an AFE IC with high frame rate using a multiple-frequency driving method (MFDM) is proposed for response to fast movements of fingers and active styli, while expressing both the pressure and tilt angle of the active stylus.

Stylus pen and touch sensing system and driving method of the same

Abstract: A touch sensing system comprises a touchscreen with a plurality of touch electrodes, to which a touchscreen driving signal is applied, and a stylus pen that generates a pen driving signal based on the touchscreen driving signal and sends the same to the touchscreen. The stylus pen comprises: an amplifier that amplifies the touchscreen driving signal to generate an amplified signal; a comparator that compares the amplified signal with a preset reference voltage to generate a comparator output signal; and a signal processor that measures the pulse width of the comparator output signal, adjusts an amount of delay based on a measurement, and determines an output timing of the pen driving signal based on an adjusted amount of delay to synchronize the pen driving signal with the touchscreen driving signal.

MEMS tunable VCSEL powered swept source OCT for 3D metrology applications

Abstract: Disclosed is an optical probe system that is capable of high speed, high precision, and high resolution 3D digitalization of engineered objects. The 3D dimensional data of the engineered object is measured using a swept source optical coherence tomography system with improved speed, spatial resolutions, and depth range. Also disclosed is a type of coordinate measurement machine (CMM) that is capable of performing high speed, high resolution, and non-contact measurement of engineered objects. The mechanic stylus in the touch-trigger probe of a conventional CMM is replaced with an optical stylus with reconfigurable diameter and length. The distance from the center of the optical stylus to the measurement probe is optically adjusted to match the height of the object to be measured quickly, which eliminates one dimensional movement of the probe and greatly improves the productivity.

Profile evaluation of radial Fresnel lens directly machined on roller molds by rotating-tool diamond turning

Abstract: In Roll-to-Roll manufacturing of high-quality optical Fresnel lens films, a high-precision roller mold with super-fine surface quality is essential to precisely transfer the functional microstructures from the periphery roller surface onto the flexible substrate. Unfortunately, direct diamond turning of deep circular grooves on the periphery surface of a roller mold was considered infeasible. Recently, the team has developed a novel 4-axis interactive tool-workpiece motion, Rotating-tool diamond turning (RDT), as a solution to overcome this challenge. Experiments were conducted to justify the capability of the proposed RDT process by directly machining a radial Fresnel lens on a brass roller mold, but without precise 3D profile evaluation of the lens on the roller surface. On-machine measurement of the machined lens structures using 3D touch probe is not applicable because the diameter of the probe is relatively large to penetrate into steep grooves of the Fresnel lens. On the other hand, off-machine measurement using stylus profilometer will introduce inevitable alignment errors during the measurement and lead to mismatched machining and measurement coordinates, making it difficult to evaluate the 3D lens profile generated by the RDT process eventually. In this study, a compensation and comparison algorithm is presented to precisely evaluate the form error between the machined and designed features in a three dimensional manner. Alignment errors generated when positioning the roller mold on the stylus profilometer are investigated and quantified through analyzing the characteristics of this unique micro structure with Fresnel lens wrapped on the roller periphery. As a conclusion, the machined lens structure is compensated and restored to compare with the designed profile, and the form error is obtained with the sources of errors analyzed. Such profile compensation and comparison method can be applied in other measurement and characterization studies on evaluation of complex optical structures patterned on roller molds for Roll-to-Roll manufacturing of advanced functional films.

Writing instrument and electronic pen body section

Abstract: A writing instrument includes a cylindrical outer housing, one end of the outer housing having an outer opening, and an electronic pen body stored in the outer housing. The electronic pen body includes a stylus, one end of the stylus in an axial direction of the stylus serving as a pen tip, and a cylindrical inner housing storing the stylus, the one end of the stylus serving as the pen tip extending from an inner opening at a distal end of the inner housing, the inner opening of the inner housing defining one axial end of a hole extending axially forming a stylus guide that enables the stylus to move axially. In operation, the pen tip of the stylus and a distal portion of the inner housing having the inner opening extend from the outer opening of the outer housing.

Touch panel controller, stylus pen, touch panel system, and electronic device

Abstract: Driving of a stylus pen is satisfactorily controlled even when the touch panel controller and the stylus pen are not connected through a wire. A touch panel (2) is driven by a touch panel controller (4), and is given with an input operation from a stylus pen (3) that is able to transmit and receive information to and from the touch panel controller (4) via wireless communication. The touch panel controller (4) includes a timing generator (14) that generates a synchronization signal to synchronize drive timing of the stylus pen (3) and drive timing of the touch panel (2) with each other, and an information signal generating unit (19) that generates an information signal representing a drive state of the touch panel (2). The information signal is transferred from the touch panel controller (4) to the stylus pen (3) subsequent to the synchronization signal.

Stylus Tip Center Position Self-Calibration Based on Invariable Distances in Light-Pen Systems.

Abstract: The light-pen coordinate measuring machine (LPCMM for short) is portable and flexible to measure features including invisible ones in-situ. Since different styluses are needed to measure different features and even during the process of measuring a single workpiece with complicated configurations, to improve the system measurement accuracy it is beneficial to calibrate the stylus tip center position after it is mounted to the light-pen before measurement in an industrial field. A novel and simple method aiming at self-calibrating the position of the tip center based on invariable distances is presented. The distinguishing feature of the proposed method is that the center position of the tip can be calibrated by using a kinematic seat with an inverted cone hole without any external reference and auxiliary devices. Calibration is based on that the distance between the tip center and that of any LED is invariable when the light-pen is swung smoothly with its spherical tip firmly touching the fixed cone seat. To ensure the repeatability of the algorithm some error constraint parameters are given. Based on invariable distances, the tip center position in the light-pen coordinate system can be obtained. Experiment results show that the self-calibration method has the advantage of good repeatability, with standard deviations 0.027, 0.023 and 0.014 mm in U, V and W directions, respectively. Experimental results of measuring a circle and a gauge block indirectly demonstrate the accuracy of the proposed self-calibration method.

Contact-less stylus for surgical navigation: registration without digitization

Abstract: We present a laser-based, contact-less, stylus for the purpose of fiducial registration and digitization in the context of surgical navigation. We augmented a laser pointer with a spatial measurement device and used the laser beam as a means to locate a fiducial in 3D space. We developed a method for calibrating the orientation of the laser beam with respect to its attached tracking target. Digitization of a fiducial was formulated as a line intersection problem, and registration was formulated as a point-to-line registration problem. We achieved an RMS fiducial localization error of 0.63 mm for 151 measurements of 12 fiducial markers. Mean TRE values of less than 1.5 mm over the entire surface of a lumbar vertebra were achievable using 4 fiducial markers. We found that contact-based rigid registration performed carefully under near-ideal conditions outperforms contact-less registration in terms of TRE. An inexpensive contact-less stylus can be used to obtain accurate fiducial registration, which can be performed without explicit fiducial digitization.

Finger-stylus for non touch-enable systems

Abstract: Since computer was invented, people are using many devices to interact with computer. Initially there were keyboard, mouse etc. but with advancement of technology, new ways are being discovered that are quite common and natural to the humans like stylus for touch-enabled systems. In the current age of technology, the user is expected to touch the machine interface to give input. Hand gesture is used in such a way to interact with machines where natural bare hand is used to communicate without touching machine interface. It gives a feeling to the user that he is interacting in a natural way with some human, not with traditional machines. This paper presents a technique where the user need not touch the machine interface to draw on the screen. Here hand finger draws shapes on monitor like stylus, without touching the monitor. This method can be used in many applications including games. The finger is used as an input device that acts like a paint-brush or finger-stylus and is used to make shapes in front of the camera. Fingertip extraction and motion tracking were done in Matlab with real time constraints. This work is an early attempt to replace stylus with the natural finger without touching the screen.

9.7 A 6.9mW 120fps 28×50 capacitive touch sensor with 41.7dB SNR for 1mm stylus using current-driven ΔΣ ADCs

Abstract: Capacitive touch sensors are essential for the user interfaces of smartphones and tablet PCs. Large touch-screen panels (TSPs) require high-quality touch features, resulting in an increased number of sensing channels as well as a reduction of sensing capacitance due to fine-pitch arrangements. Therefore, touch-sensor ICs demand high resolution, low power and high efficiency. State-of-the-art capacitive touch sensors [1–6] mostly rely on capacitive charge amplifiers as analog front-ends (AFEs), which convert the capacitor change into a voltage signal and often limit the system noise figure, thus consuming most of the power. This paper presents a 120fps 28×50 touch sensor that achieves 41.7dB SNR for 1mm-φ stylus, while consuming 6.9mW, which results in an energy efficiency of 0.41nJ/step, for a >4× improvement compared to state-of-the-art stylus touch sensors (see Fig. 9.7.6). This is achieved by a current-driven ΔΣ ADC architecture, which implements charge balancing between a reference charge and a differential current from adjacent channels, directly interfacing with 2nd-order ΔΣ modulators. An area-efficient sinc2 filter, as a decimation filter, enables full parallel implementation of the 2nd-order ΔΣ ADCs, providing sufficient suppression of interference signals. In contrast to previous works, the current-driven ΔΣ ADC only needs to digitize small differential currents, which relaxes requirements of the front-end amplifier, resulting in a large power reduction.

Stylus and sensor controller

Abstract: A stylus is provided, which includes a core body, an electrode disposed adjacent to the core body, a transmitter that sends a downlink signal including switch information SW 1 using the electrode, and a controller that determines whether the stylus is in contact state with an operating surface or the stylus is in hover state. In the contact state, the controller controls the transmitter to send the switch information SW 1 at a first bit rate. In the hover state, the controller controls the transmitter to send the switch information SW 1 at a second bit rate smaller than the first bit rate. A technical advantage includes lowering the possibility of a failure to receive downlink signals when the stylus is in hover state, even though the stylus sends the downlink signals with the same intensity as when the stylus is in contact state.

Dynamic User Interface Adaptable to Multiple Input Tools

Abstract: A computing device having a touch-sensitive surface and a display, detects a stylus input on the touch-sensitive surface while displaying a user interface A first operation is performed in the user interface in accordance with a determination that the stylus input includes movement of the stylus across the touch-sensitive surface while the stylus is detected on the touch-sensitive surface A second operation different from the first operation is performed in the user interface in accordance with a determination that the stylus input includes rotation of the stylus around an axis of the stylus while the stylus is detected on the touch-sensitive surface A third operation is performed in the user interface in accordance with a determination that the stylus input includes movement of the stylus across the touch-sensitive surface and rotation of the stylus around an axis of the stylus while the stylus is detected on the touch-sensitive surface

Development of CO2 snow cleaning for in situ cleaning of µCMM stylus tips

Abstract: Contamination adhered to the surface of a µCMM stylus tip compromises the measurement accuracy of the µCMM system, potentially causing dimensional errors that are over ten times larger than the uncertainty of a modern µCMM. In prior work by the authors, the use of a high pressure CO2 gas stream was demonstrated to achieve significant cleaning rate for a range of contaminant without damage to the stylus tip surface. This paper explores the practical challenges of achieving effective stylus tip cleaning in situ on µCMM systems. Two types of snow cleaning approaches were evaluated for their coverage of cleaning, thermal impact and gas flow forces. This work then presents a novel multi-nozzle prototype system using pulsed snow streams to achieve cleaning coverage over the entire stylus tip, and balances forces from the snow streams reducing drag force imparted by the gas stream to levels comparable to the probing force of µCMMs, as well as allowing automated cleaning procedure integrated into a µCMM system.

Surface roughness characterisation of turned surfaces using image processing

Abstract: Industrial measurement of surface roughness is primarily stylus-based. Stylus-based surface roughness measurement has limitation of the stylus tip diameter acting as a filter on steep valleys. It is also a time consuming and an offline process. Vision-based system for surface roughness measurement has potential to emerge as a reliable online surface roughness measuring system, because of the emergence of powerful cameras and superior image processing techniques. The presented work is an attempt to create a technique for evaluation of surface roughness using vision-based image processing. First a group of two-dimensional images of turned surfaces was obtained and using MATLAB the image pixel intensity distribution parameters were calculated for each of these surface images. Mean and standard deviation were the two statistical parameters used to characterise the surface roughness using the pixel intensity of the turned surface images. Standard deviation was found to correlate better with Ra, Rda and Rdq values of the surface roughness. Hence, the technique may be preferred for online surface characterisation of turned surfaces.

Touch sensitive processing method, apparatus and system for setting palm rejection area

Abstract: The present invention provides a touch sensitive processing method for setting a palm rejection area. The method includes: setting a vertex of a palm rejection area based on a proximity or touch location of a stylus; setting a rejection area baseline vector extending from the vertex based on a stylus shaft vector of the stylus projected on a touch screen; defining an area covered by rotating the rejection area baseline vector around the vertex by a clockwise angle and an anticlockwise angle as the palm rejection area; and ignoring any proximity or touch event of an external conductive object detected in the palm rejection area.

Assessment of the state of the geometrical surface texture of seal rings by various measuring methods

Abstract: The present paper concerns the metrological measurements of the geometric structure of the faces of seal rings made of silicon carbide and carbon-graphite. Three different instruments, i.e. the stylus profilometer, the optical profilometer, and the atomic force microscope, were used to measure the geometric structure of surfaces. In the comparative analysis, an identical area of the ring surface which was mapped by three measuring instruments with different sampling densities resulting from their metrological characteristics was assumed. The measurements made show that for the silicon carbide ring, the surface texture measurements on an atomic force microscope and optical instruments more accurately represent the actual topography than the measurement determined by the stylus profilometer.

Digitally) Inking in the 21st Century

Abstract: The ubiquity and mobility of contemporary computing devices has enabled users to consume content, anytime, anywhere. Yet, when we need to create content, touch input is far from perfect. When coupled with touch input, the stylus should enable users to simultaneously ink, manipulate the page, and switch between tools with ease, so why has the stylus yet to achieve universal adoption? Michelle Annett's thesis sought to understand the usability barriers and tensions that have prevented stylus input from gaining traction and reaching widespread adoption. This article in particular explores the limits of human latency perception and evaluates solutions to unintended touch.

Stylus Knife for Paper-cutting: A System for Controlling a Knife

Abstract: We introduce a Stylus Knife that has a blade attached to the tip of a touch pen. This device can measure pressure when an artist cuts paper. In the past, we determined that knife pressure is important for creating paper-cutting designs. Therefore, we developed a device on a tablet computer to measure pressure when the user cuts paper. In an experiment, to confirm the effectiveness of our device, we compared it with a general utility knife that had a pressure sensor. Our test procedure was as follows: 1) our subjects cut paper with utility knife, and 2) each subject performs paper cutting using each device. For our experiment, we used seven subjects in each of three groups: G1 (practice using the Stylus Knife), G2 (practice using only the utility knife), and G3 (practice using the utility knife with a textbook). We compared the changes between Steps 1 and 2 exhibited by each group. As a result, group G1was able to apply sufficient pressure for a line pattern, while the others cut a line pattern with insufficient pressure. We confirmed that the novice subjects were able to cut paper with appropriate pressure by using our knife.

Using hover to compromise the confidentiality of user input on Android

Abstract: We show that the new hover (floating touch) technology, available in a number of today's smartphone models, can be abused by malicious Android applications to record all touchscreen input into applications system-wide. Leveraging this attack, a malicious application running on the system is able to capture sensitive input such as passwords and PINs, record all user's social interactions, as well as profile user's behavior. To evaluate our attack we implemented Hoover, a proof-of-concept malicious application that runs in the background and records all input to all foreground applications. We evaluated Hoover with 20 users, across two different Android devices and two input methods, stylus and finger. In the case of touchscreen input by finger, Hoover estimated the positions of users' clicks within an error of 100 pixels and keyboard input with an accuracy of 79%. Hoover captured users' input by stylus even more accurately, estimating users' clicks within 2 pixels and keyboard input with an accuracy of 98%. Differently from existing well-known side channel attacks, this is the first work that proves the security implications of the hover technology and its potential to steal all user inputs with high granularity. We discuss ways of mitigating this attack and show that this cannot be done by simply restricting access to permissions or imposing additional cognitive load on the users since this would significantly constrain the intended use of the hover technology.

A microscopy approach for in situ inspection of micro-coordinate measurement machine styli for contamination

Abstract: During the µCMM measurement process, contamination gradually builds up on the surface of the stylus tip and affects dimensional accuracy of the measurement. Regular inspection of the stylus for contamination is essential in determining the appropriate cleaning interval and preventing the dimensional error from becoming significant. However, in situ inspection of a µCMM stylus is challenging due to the size, spherical shape, material and surface properties of a typical stylus. To address the challenges, this study evaluates several non-contact measurement technologies for in situ stylus inspection and based on those findings proposes a cost-effective microscopy approach. The operational principle is then demonstrated by an automated prototype, coordinated directly by the CMM software MCOSMOS, with an effective threshold of detection as low as 400 nm and large field of view and depth-of-field. The level of stylus contamination on the stylus has been found to increase steadily with the number of measurement contacts made. Once excessive contamination is detected on the stylus, measurement should be stopped and stylus cleaning procedure should be performed to avoid affecting measurement accuracy.

Finger or Stylus: Their Impact on the Performance of On-line Signature Verification Systems

Abstract: Abstract The widespread use of smartphones and the ability of these devices to digitize signatures have made it possible to sign electronic documents in this way. In this paper we compared two on-line signature databases in terms of verification performance: the MCYT containing signatures drawn by stylus pen, and MOBISIG containing finger drawn signatures. Performance evaluations were performed using both local and global systems. In the case of global systems, we evaluated the performance of a novel information theory features set. Little improvement was achieved by this feature set. There were large differences between the two databases in terms of performance. Finger drawn signatures collected by mobile device were proved inferior to signatures collected by digitizing tablet and its stylus.

Change of active user of a stylus pen with a multi user-interactive display

Abstract: In a multi-user, collaborative environment, an operating system state change can occur by passing a stylus pen from one user to another. Upon detecting a change of the active user, a state machine transition can result in a change in a user experience. In one example, a change in the user experience includes a change in user interface (UI) functionality. Some examples include changing color of the digital ink being displayed, changing a handwriting pattern, and automatically switching a view displayed on the user interface. The switched view can be switching from a single-user model to a multi-user model. In another example, a state machine transition can result in establishing connections between devices (e.g., phones or laptops) associated with the users that used the pen.