Mel Siegel | Carnegie Mellon University (original) (raw)

Papers by Mel Siegel

This study investigated the effectiveness of force augmentation in haptic perception tasks. Backg... more This study investigated the effectiveness of force augmentation in haptic perception tasks. Background: Considerable engineering effort has been devoted to developing force augmented reality (AR) systems to assist users in delicate procedures like microsurgery. In contrast, far less has been done to characterize the behavioral outcomes of these systems, and no research has systematically examined the impact of sensory and perceptual processes on force augmentation effectiveness. Method: Using a handheld force magnifier as an exemplar haptic AR, we conducted three experiments to characterize its utility in the perception of force and stiffness. Experiments 1 and 2 measured, respectively, the user's ability to detect and differentiate weak force (<0.5 N) with or without the assistance of the device and compared it to direct perception. Experiment 3 examined the perception of stiffness through the force augmentation. Results: The user's ability to detect and differentiate small forces was significantly improved by augmentation at both threshold and suprathreshold levels. The augmentation also enhanced stiffness perception. However, although perception of augmented forces matches that of the physical equivalent for weak forces, it falls off with increasing intensity. Conclusion: The loss in the effectiveness reflects the nature of sensory and perceptual processing. Such perceptual limitations should be taken into consideration in the design and development of haptic AR systems to maximize utility. Application: The findings provide useful information for building effective haptic AR systems, particularly for use in microsurgery.

Introduction 3 Configuration 3.1 Target 3.2 Sensor 3.3 Initialization Procedure 3.3.1 Waist Joint... more Introduction 3 Configuration 3.1 Target 3.2 Sensor 3.3 Initialization Procedure 3.3.1 Waist Joint Initialization 3.3.2 Shoulder and Elbow Joint Initialization 4.1 Accuracy as a Function of Initialization Cycles 4.2 Relationship Between Accuracy of Initialization and Original Elbow Angle 4.3 Relationship Between Accuracy of the Initialization and Parameters B , K, and D 4.4 Considerations About Elbow Orientation 4.5 Considerations About the Wrist Joint 4 Initialization Accuracy Analysis

A low-cost optical sensory sorting system is described. The sensor is directly mounted on robot g... more A low-cost optical sensory sorting system is described. The sensor is directly mounted on robot gripper fingers, a light source on one and a coherent bundle of optical fibers on the opposing one. The optical fibers carry the shadow of a gripped object, as an eight-by-eight pixel array, to detection, multiplexing, discrimination, and computer interface electronics mounted on the robot base. The system uses a microcomputer for several data processing and pattern recognition functions. This discussion covers the design and analysis of the sensor and its optimal array, the hardware, and the parts recognition and control system. System performance in a demonstration task requiring the acquisition, identification, and sorting of a variety of electronic and mechanical parts is described.

SECURitrY CLASSIFICATION4 Oft-IS PA. 'When Date Enfvrodl-. REPOR DOCMENTTIONPAGEREAD INST RUCTION... more SECURitrY CLASSIFICATION4 Oft-IS PA. 'When Date Enfvrodl-. REPOR DOCMENTTIONPAGEREAD INST RUCTIONS REPRT OCUENTTIO PAEI BPFORE CC'!PLETING FORM REPORT NuU3. GOVI ACCESSION NOJ1 3. RECIPIENT'S CATAL'50 NUM&ER 4 ?ITLE (nd Sbites) DD 1 I JAPI1 1473 EDITION GOP I NOV O5 IS OBSOLETE Unclassified SECURITY CLASSIFICATION OF TIS PAGE (0)..t Does Sneered) %I (20 cont'd) large first and second harmonic terms for physically reasonable values of the parameters. The first harmonic signal is proportional to the product of the dither amplitude and the offset. The second harmonic signal is proportional to the square of the dither amplitude and is independent of offset. The two coefficients are identical except for an integral numerical factor. It is suggested that the ratio of second harmonic to first harmonic signals is thus potentially a powerful measure of offset, i.e., of focusing error in the limit of zero dither, and thus of range-from-focus pixel-by-pixel. Fxtending the model to three dimcnsions, removing GIe approximations, extending the model to natural scenes, and verifying and implementing the results experimentally are outlined briefly. .,

We describe the technology and characteristics of a family of thick-film gas sensors as simple to... more We describe the technology and characteristics of a family of thick-film gas sensors as simple to manufacture as a oneelement sensor, but whose signal can be as rich as that of an array of twenty-five or more discrete sensors. This sensor design is particularly well adapted to using pattern recognition and related methods of analyte identification and quantitation based on the co-interpreted response of multiple sensors. Our (TM) prototype sensors are constructed on alumina Snapstrates intended for 20-pin DIP hybrid circuit substrates. A printed precious metal alloy electrode pattern provides pin connection pads, electrodes for mapping the gas-sensitive resistance of the overprinted metal oxide thick-film, and connections to an overprinted ohmic heater. Gradients in one or two different catalytic properties can be imposed across the short dimension and along the long dimension of the film. Each gradient can be continuous, for example a catalyst concentration gradient across or along the film, or discrete, for example three stripes across or nine stripes along the film, each of different but uniform catalyst concentration and composition. Depending on the electrode pattern used, the resistances of up to twentyfive usefully distinct surface regions can be measured. While these regions are effectively separate sensors, they share an identical history, and in operation share an identical environment. Thus differential effects from region to region can be attributed with certainty to differential responses to the same sample. Several electrode patterns and thick-film formulations have been investigated. Measurements to date confirm the validity of the design, and suggest directions in which evolution of the fabrication technology might be directed. Future possibilities include making essentially continuous surfacelocation-resolved measurements, adding gradients in the third spatial dimension, and using temporal as well as spatial gradients.

This paper introduces prototype experimental apparatus and the calibration and real-time signal p... more This paper introduces prototype experimental apparatus and the calibration and real-time signal processing required to investigate stability in standing, walking and running of humanoid robots using pressure sensing at the sole-of-the-foot contact. The system can provide very good spatial or temporal resolution and these can be traded off against each other dynamically to accommodate the instantaneous requirement, for example, sparsely sampling the whole sole during static balancing vs. densely sampling the impact region during walking or running. Dynamic variation in sampling policy during different phases of the gait is foreseen so as to optimise utilisation of the total sampling bandwidth available. Periodic signals like walking and running would be sampled repetitively, achieving by accumulation both high spatial and high temporal resolution.

Remotely or automatically operated vehicles (mobile "robots") for deploying visual and NDI inspec... more Remotely or automatically operated vehicles (mobile "robots") for deploying visual and NDI inspection equipment are critically reviewed. After a brief introduction, reasons for using robots for aircraft skin inspection are reviewed. General design scenarios for robotic systems are then reviewed. Actual designs for five substantial US efforts are then described and illustrated, and the performance of these designs is discussed. Some smaller US and overseas efforts are mentioned briefly. The closing section discusses the lessons of efforts to date and suggests a course of action for the future.

Visual inspection is the most widely used method in commercial aircraft surface inspection. We ha... more Visual inspection is the most widely used method in commercial aircraft surface inspection. We have developed a prototype remote visual inspection system, designed to facilitate testing the feasibility and advantages of remote visual inspection of aircraft surfaces. We describe experiments with image understanding algorithms to aid remote visual inspection by enhancing and recognizing surface cracks and corrosion from live imagery. Also described are the supporting mobile robot platform that delivers the imagery, and the inspection console through which the inspector accesses it. We discuss initial results of the image understanding algorithms and speculate on their future use in aircraft surface inspection.

Neurocomputing, Apr 1, 2016

This paper presents a new descriptor, multi-sparse descriptor (MSD), for pedestrian detection in ... more This paper presents a new descriptor, multi-sparse descriptor (MSD), for pedestrian detection in static images. Specifically, the proposed descriptor is based on multi-dictionary sparse coding which contains unsupervised dictionary learning and sparse coding. During unsupervised learning phase, a family of dictionaries with different representation abilities is learnt from the pedestrian data. Then the data are encoded by these dictionaries and the histogram of the sparse coefficients is calculated as the descriptor. The benefit of this multi-dictionary sparse encoding is threefold: firstly, the dictionaries are learnt from the pedestrian data, they are more efficient for encoding local structures of the pedestrian; secondly, multiple dictionaries can enrich the representation by providing different levels of abstractions; thirdly, since the dictionaries based representation is mainly focused on the low frequency, better generalization ability along the scale range is obtained. Comparisons with the state-of-the-art methods reveal the superiority of the proposed method.

Aircraft flight pressurization/depressurization cycles cause their skins to inflate and deflate, ... more Aircraft flight pressurization/depressurization cycles cause their skins to inflate and deflate, stressing the skin around the rivets that fasten it to the airframe. The resulting strain, exacerbated by any corrosion that might be present, drives the growth of the initially microscopic cracks that are an unavoidable by-product of rivet installation. To avoid catastrophe, aircraft are periodically inspected for cracks and corrosion. The inspection technology employed is ~90% naked-eye vision. Of the ~10% that is instrumented, ~90% is with hand-held eddy current pencil probes. We have developed and demonstrated robotic deployment of remote eddy current and remote enhanced stereoscopic video instrumentation, augmented by image enhancement and image understanding algorithms, aimed at alleviating human performance problems and workplace hazards in inspection. This paper describes the aircraft skin inspection application, our two robotic deployment systems, the corresponding instrumentation packages we have demonstrated, and our progress toward developing image enhancement and understanding techniques to assist aircraft inspectors in finding cracks and corrosion. A wavelet-based approach is able to select radial features around rivets, and then to discriminate between cracks and scratches.

IEEE Journal of Translational Engineering in Health and Medicine, 2014

We present a novel device mounted on the fingertip for acquiring and transmitting visual informat... more We present a novel device mounted on the fingertip for acquiring and transmitting visual information through haptic channels. In contrast to previous systems in which the user interrogates an intermediate representation of visual information, such as a tactile display representing a camera generated image, our device uses a fingertip-mounted camera and haptic stimulator to allow the user to feel visual features directly from the environment. Visual features ranging from simple intensity or oriented edges to more complex information identified automatically about objects in the environment may be translated in this manner into haptic stimulation of the finger. Experiments using an initial prototype to trace a continuous straight edge have quantified the user's ability to discriminate the angle of the edge, a potentially useful feature for higher levels analysis of the visual scene.

Modulated beams of 0 + , Ar + , and Kr + in the 100-300 eV range are directed into a copper box s... more Modulated beams of 0 + , Ar + , and Kr + in the 100-300 eV range are directed into a copper box simulating the antechamber of an orbiting mass spectrometer. An RF quadrupole mass spectrometer and phase sensitive detection extract the component of the internal mass spectrum correlated with the beam. Intense Ar and Kr signals are observed; however, no 0 or 0 2 is detectable, indicating loss of the primary 0 beam to surface interactions. All four primary ions stimulate sizeable signals at masses 26 and 28. The relevance of these experiments to the interpretation of mass spectra obtained by orbiting satellites is discussed.

Pressure ulcers are volumes of tissue necrosis that evolve after prolonged exposure of skin and s... more Pressure ulcers are volumes of tissue necrosis that evolve after prolonged exposure of skin and soft tissue to the forces of reclining or sitting. They are serious problems for people confined to beds and wheelchairs. Treating them is expensive, and if untreated fatal infections can evolve, so substantial clinical effort is focussed on prevention. However the precise conditions for and mechanisms of ulcer development and evolution are poorly understood, so prevention is largely ad hoc.

The characteristics of pulsed diode lasers and linear CCD array optical detectors are explored in... more The characteristics of pulsed diode lasers and linear CCD array optical detectors are explored in the context of high speed precision dimension and location measurements by optical diffraction and interference. It is suggested that pixel based metrology may, with appropriate signal extraction and processing methods, be made more accurate by making edges less well defined: if the mechanism of definition loss is well understood, e.g., diffraction, the intensity distribution over many pixels can be matched to a template to within a small fraction of a pixel, obviating the need to make sub-pixel interpolations based on local intensities. The specific example of making remote flash measurements of the diameter and location of an opaque cylindrical object, e.g., a fast-moving textile strand, is examined. A model is developed for calculating the diffraction pattern given the target and instrument parameters. The results are examined and compared with experimental data. Algorithms for finding the diameter and location given the diffraction and interference pattern and the instrument parameters are described. The performance statistics of a prototype instrument are measured in a data run of 1000 laser shots. Location and diameter measurement standard deviations are 0.13 pixel-widths (1.69 rum) and 0.36 pixel-widths (4.68 ptm) respectively, implying that sub-micron precisions are obtainable by averaging a few dozen measurements. Sources of drift and scatter, and their reduction, are discussed in the context of designing and building an improved second generation instrument. .. .. • .-. ,~m.n== mmmnni aimm • il ~ mni l NmH~mm"I

We describe a nd demonstrate an ambient lllumlnation method for range Imaging In parallel with an... more We describe a nd demonstrate an ambient lllumlnation method for range Imaging In parallel with and using the same sensor that is used for Intensity Imaging. Our method automates the well known "range-from-focus" method. It makes use of our reaiizatlon that range can be calculated directly from a focus error signal: It is not necessary to actually focus the Image, only to measure the focus; error. We show theoretically and demonstrate experlmentaIly that the focus error distance can b e measured by time domain fourler analysls of the signal from a sensor that Is mlcroscoplcally oscillated ("dithered") longitudinally in the space domain. In an approximation regime that our experiments show to be physically realistic, the ratio of the first two significant fourier amplitudes is proportional to the ratio of the focus error to the dither amplitude. Since the illuminatlon, the reflectance, and most technical noise sources affect all fourler amplitudes in an equal multiplicative fashion, the fourler amplitude ratio is a robust measure of the focus error to dither amplitude ratio. The constants needed to calculate absolute range images are the focal length of the lens, the sensor's mean position, and the dither amlpiitude. Experiments using a 50 mm W1.5 camera lens, a pinhole object, and a single detector dithered by an audio speaker demonstrate real-time range resolution of approxlmately 0.5 mun at a range of 350mm. Modelling lndlcatrs that the method, implemented with a sensor array, Is also applicable to extended objects. Plans for extending the experiments to real scenes are discussed.

Measurement Technology and Intelligent Instruments, Sep 22, 1993

We present a novel concept, vector restoration, for motion compensated predictive coding of video... more We present a novel concept, vector restoration, for motion compensated predictive coding of video. Conventional predictive coders generate predictions of the input signal and encode the residual signal. Here, the predicted images are operated upon directly with the goal of restoring the original images at the decoder. The predicted images are processed in a piecewise manner using restoration functions chosen from a codebook. Compression is achieved by transmitting only an index of the chosen restoration function for each image region. We describe the manner in which the restoration functions are generated and chosen. Vector restoration is shown to outperform residual vector quantization and transform-based coders. This superiority is due to vector restoration's ability to adaptively exploit the non-trivial correlation between the predicted and residual images.

The FAA Aging Aircraft Research Program is supporting the development of a robotic mobile nondest... more The FAA Aging Aircraft Research Program is supporting the development of a robotic mobile nondestructive inspection (NDI) instrument deployment tool at Carnegie Mellon University (CMU) with the active participation of USAir. The program has spawned several new relationships and entities: an alliance with an ARPA-funded research program at CMU having the capability to add 3D-stereoscopic enhanced visual inspection capability, a start-up company organized to commercialize the combined technologies, and State of Pennsylvania funding to foster this commercialization. As a result of these activities and connections the civilian sector appears to be ahead of the military sector in important aspects of automation for deployment of aircraft inspection equipment. A partnership between the university researchers, the airline operator, the start-up company, and the state government is thus emerging as the likely agent for transfer of the civilian-developed technology to the military sector.

This study investigated the effectiveness of force augmentation in haptic perception tasks. Backg... more This study investigated the effectiveness of force augmentation in haptic perception tasks. Background: Considerable engineering effort has been devoted to developing force augmented reality (AR) systems to assist users in delicate procedures like microsurgery. In contrast, far less has been done to characterize the behavioral outcomes of these systems, and no research has systematically examined the impact of sensory and perceptual processes on force augmentation effectiveness. Method: Using a handheld force magnifier as an exemplar haptic AR, we conducted three experiments to characterize its utility in the perception of force and stiffness. Experiments 1 and 2 measured, respectively, the user's ability to detect and differentiate weak force (<0.5 N) with or without the assistance of the device and compared it to direct perception. Experiment 3 examined the perception of stiffness through the force augmentation. Results: The user's ability to detect and differentiate small forces was significantly improved by augmentation at both threshold and suprathreshold levels. The augmentation also enhanced stiffness perception. However, although perception of augmented forces matches that of the physical equivalent for weak forces, it falls off with increasing intensity. Conclusion: The loss in the effectiveness reflects the nature of sensory and perceptual processing. Such perceptual limitations should be taken into consideration in the design and development of haptic AR systems to maximize utility. Application: The findings provide useful information for building effective haptic AR systems, particularly for use in microsurgery.

Introduction 3 Configuration 3.1 Target 3.2 Sensor 3.3 Initialization Procedure 3.3.1 Waist Joint... more Introduction 3 Configuration 3.1 Target 3.2 Sensor 3.3 Initialization Procedure 3.3.1 Waist Joint Initialization 3.3.2 Shoulder and Elbow Joint Initialization 4.1 Accuracy as a Function of Initialization Cycles 4.2 Relationship Between Accuracy of Initialization and Original Elbow Angle 4.3 Relationship Between Accuracy of the Initialization and Parameters B , K, and D 4.4 Considerations About Elbow Orientation 4.5 Considerations About the Wrist Joint 4 Initialization Accuracy Analysis

A low-cost optical sensory sorting system is described. The sensor is directly mounted on robot g... more A low-cost optical sensory sorting system is described. The sensor is directly mounted on robot gripper fingers, a light source on one and a coherent bundle of optical fibers on the opposing one. The optical fibers carry the shadow of a gripped object, as an eight-by-eight pixel array, to detection, multiplexing, discrimination, and computer interface electronics mounted on the robot base. The system uses a microcomputer for several data processing and pattern recognition functions. This discussion covers the design and analysis of the sensor and its optimal array, the hardware, and the parts recognition and control system. System performance in a demonstration task requiring the acquisition, identification, and sorting of a variety of electronic and mechanical parts is described.

SECURitrY CLASSIFICATION4 Oft-IS PA. 'When Date Enfvrodl-. REPOR DOCMENTTIONPAGEREAD INST RUCTION... more SECURitrY CLASSIFICATION4 Oft-IS PA. 'When Date Enfvrodl-. REPOR DOCMENTTIONPAGEREAD INST RUCTIONS REPRT OCUENTTIO PAEI BPFORE CC'!PLETING FORM REPORT NuU3. GOVI ACCESSION NOJ1 3. RECIPIENT'S CATAL'50 NUM&ER 4 ?ITLE (nd Sbites) DD 1 I JAPI1 1473 EDITION GOP I NOV O5 IS OBSOLETE Unclassified SECURITY CLASSIFICATION OF TIS PAGE (0)..t Does Sneered) %I (20 cont'd) large first and second harmonic terms for physically reasonable values of the parameters. The first harmonic signal is proportional to the product of the dither amplitude and the offset. The second harmonic signal is proportional to the square of the dither amplitude and is independent of offset. The two coefficients are identical except for an integral numerical factor. It is suggested that the ratio of second harmonic to first harmonic signals is thus potentially a powerful measure of offset, i.e., of focusing error in the limit of zero dither, and thus of range-from-focus pixel-by-pixel. Fxtending the model to three dimcnsions, removing GIe approximations, extending the model to natural scenes, and verifying and implementing the results experimentally are outlined briefly. .,

We describe the technology and characteristics of a family of thick-film gas sensors as simple to... more We describe the technology and characteristics of a family of thick-film gas sensors as simple to manufacture as a oneelement sensor, but whose signal can be as rich as that of an array of twenty-five or more discrete sensors. This sensor design is particularly well adapted to using pattern recognition and related methods of analyte identification and quantitation based on the co-interpreted response of multiple sensors. Our (TM) prototype sensors are constructed on alumina Snapstrates intended for 20-pin DIP hybrid circuit substrates. A printed precious metal alloy electrode pattern provides pin connection pads, electrodes for mapping the gas-sensitive resistance of the overprinted metal oxide thick-film, and connections to an overprinted ohmic heater. Gradients in one or two different catalytic properties can be imposed across the short dimension and along the long dimension of the film. Each gradient can be continuous, for example a catalyst concentration gradient across or along the film, or discrete, for example three stripes across or nine stripes along the film, each of different but uniform catalyst concentration and composition. Depending on the electrode pattern used, the resistances of up to twentyfive usefully distinct surface regions can be measured. While these regions are effectively separate sensors, they share an identical history, and in operation share an identical environment. Thus differential effects from region to region can be attributed with certainty to differential responses to the same sample. Several electrode patterns and thick-film formulations have been investigated. Measurements to date confirm the validity of the design, and suggest directions in which evolution of the fabrication technology might be directed. Future possibilities include making essentially continuous surfacelocation-resolved measurements, adding gradients in the third spatial dimension, and using temporal as well as spatial gradients.

This paper introduces prototype experimental apparatus and the calibration and real-time signal p... more This paper introduces prototype experimental apparatus and the calibration and real-time signal processing required to investigate stability in standing, walking and running of humanoid robots using pressure sensing at the sole-of-the-foot contact. The system can provide very good spatial or temporal resolution and these can be traded off against each other dynamically to accommodate the instantaneous requirement, for example, sparsely sampling the whole sole during static balancing vs. densely sampling the impact region during walking or running. Dynamic variation in sampling policy during different phases of the gait is foreseen so as to optimise utilisation of the total sampling bandwidth available. Periodic signals like walking and running would be sampled repetitively, achieving by accumulation both high spatial and high temporal resolution.

Remotely or automatically operated vehicles (mobile "robots") for deploying visual and NDI inspec... more Remotely or automatically operated vehicles (mobile "robots") for deploying visual and NDI inspection equipment are critically reviewed. After a brief introduction, reasons for using robots for aircraft skin inspection are reviewed. General design scenarios for robotic systems are then reviewed. Actual designs for five substantial US efforts are then described and illustrated, and the performance of these designs is discussed. Some smaller US and overseas efforts are mentioned briefly. The closing section discusses the lessons of efforts to date and suggests a course of action for the future.

Visual inspection is the most widely used method in commercial aircraft surface inspection. We ha... more Visual inspection is the most widely used method in commercial aircraft surface inspection. We have developed a prototype remote visual inspection system, designed to facilitate testing the feasibility and advantages of remote visual inspection of aircraft surfaces. We describe experiments with image understanding algorithms to aid remote visual inspection by enhancing and recognizing surface cracks and corrosion from live imagery. Also described are the supporting mobile robot platform that delivers the imagery, and the inspection console through which the inspector accesses it. We discuss initial results of the image understanding algorithms and speculate on their future use in aircraft surface inspection.

Neurocomputing, Apr 1, 2016

This paper presents a new descriptor, multi-sparse descriptor (MSD), for pedestrian detection in ... more This paper presents a new descriptor, multi-sparse descriptor (MSD), for pedestrian detection in static images. Specifically, the proposed descriptor is based on multi-dictionary sparse coding which contains unsupervised dictionary learning and sparse coding. During unsupervised learning phase, a family of dictionaries with different representation abilities is learnt from the pedestrian data. Then the data are encoded by these dictionaries and the histogram of the sparse coefficients is calculated as the descriptor. The benefit of this multi-dictionary sparse encoding is threefold: firstly, the dictionaries are learnt from the pedestrian data, they are more efficient for encoding local structures of the pedestrian; secondly, multiple dictionaries can enrich the representation by providing different levels of abstractions; thirdly, since the dictionaries based representation is mainly focused on the low frequency, better generalization ability along the scale range is obtained. Comparisons with the state-of-the-art methods reveal the superiority of the proposed method.

Aircraft flight pressurization/depressurization cycles cause their skins to inflate and deflate, ... more Aircraft flight pressurization/depressurization cycles cause their skins to inflate and deflate, stressing the skin around the rivets that fasten it to the airframe. The resulting strain, exacerbated by any corrosion that might be present, drives the growth of the initially microscopic cracks that are an unavoidable by-product of rivet installation. To avoid catastrophe, aircraft are periodically inspected for cracks and corrosion. The inspection technology employed is ~90% naked-eye vision. Of the ~10% that is instrumented, ~90% is with hand-held eddy current pencil probes. We have developed and demonstrated robotic deployment of remote eddy current and remote enhanced stereoscopic video instrumentation, augmented by image enhancement and image understanding algorithms, aimed at alleviating human performance problems and workplace hazards in inspection. This paper describes the aircraft skin inspection application, our two robotic deployment systems, the corresponding instrumentation packages we have demonstrated, and our progress toward developing image enhancement and understanding techniques to assist aircraft inspectors in finding cracks and corrosion. A wavelet-based approach is able to select radial features around rivets, and then to discriminate between cracks and scratches.

IEEE Journal of Translational Engineering in Health and Medicine, 2014

We present a novel device mounted on the fingertip for acquiring and transmitting visual informat... more We present a novel device mounted on the fingertip for acquiring and transmitting visual information through haptic channels. In contrast to previous systems in which the user interrogates an intermediate representation of visual information, such as a tactile display representing a camera generated image, our device uses a fingertip-mounted camera and haptic stimulator to allow the user to feel visual features directly from the environment. Visual features ranging from simple intensity or oriented edges to more complex information identified automatically about objects in the environment may be translated in this manner into haptic stimulation of the finger. Experiments using an initial prototype to trace a continuous straight edge have quantified the user's ability to discriminate the angle of the edge, a potentially useful feature for higher levels analysis of the visual scene.

Modulated beams of 0 + , Ar + , and Kr + in the 100-300 eV range are directed into a copper box s... more Modulated beams of 0 + , Ar + , and Kr + in the 100-300 eV range are directed into a copper box simulating the antechamber of an orbiting mass spectrometer. An RF quadrupole mass spectrometer and phase sensitive detection extract the component of the internal mass spectrum correlated with the beam. Intense Ar and Kr signals are observed; however, no 0 or 0 2 is detectable, indicating loss of the primary 0 beam to surface interactions. All four primary ions stimulate sizeable signals at masses 26 and 28. The relevance of these experiments to the interpretation of mass spectra obtained by orbiting satellites is discussed.

Pressure ulcers are volumes of tissue necrosis that evolve after prolonged exposure of skin and s... more Pressure ulcers are volumes of tissue necrosis that evolve after prolonged exposure of skin and soft tissue to the forces of reclining or sitting. They are serious problems for people confined to beds and wheelchairs. Treating them is expensive, and if untreated fatal infections can evolve, so substantial clinical effort is focussed on prevention. However the precise conditions for and mechanisms of ulcer development and evolution are poorly understood, so prevention is largely ad hoc.

The characteristics of pulsed diode lasers and linear CCD array optical detectors are explored in... more The characteristics of pulsed diode lasers and linear CCD array optical detectors are explored in the context of high speed precision dimension and location measurements by optical diffraction and interference. It is suggested that pixel based metrology may, with appropriate signal extraction and processing methods, be made more accurate by making edges less well defined: if the mechanism of definition loss is well understood, e.g., diffraction, the intensity distribution over many pixels can be matched to a template to within a small fraction of a pixel, obviating the need to make sub-pixel interpolations based on local intensities. The specific example of making remote flash measurements of the diameter and location of an opaque cylindrical object, e.g., a fast-moving textile strand, is examined. A model is developed for calculating the diffraction pattern given the target and instrument parameters. The results are examined and compared with experimental data. Algorithms for finding the diameter and location given the diffraction and interference pattern and the instrument parameters are described. The performance statistics of a prototype instrument are measured in a data run of 1000 laser shots. Location and diameter measurement standard deviations are 0.13 pixel-widths (1.69 rum) and 0.36 pixel-widths (4.68 ptm) respectively, implying that sub-micron precisions are obtainable by averaging a few dozen measurements. Sources of drift and scatter, and their reduction, are discussed in the context of designing and building an improved second generation instrument. .. .. • .-. ,~m.n== mmmnni aimm • il ~ mni l NmH~mm"I

We describe a nd demonstrate an ambient lllumlnation method for range Imaging In parallel with an... more We describe a nd demonstrate an ambient lllumlnation method for range Imaging In parallel with and using the same sensor that is used for Intensity Imaging. Our method automates the well known "range-from-focus" method. It makes use of our reaiizatlon that range can be calculated directly from a focus error signal: It is not necessary to actually focus the Image, only to measure the focus; error. We show theoretically and demonstrate experlmentaIly that the focus error distance can b e measured by time domain fourler analysls of the signal from a sensor that Is mlcroscoplcally oscillated ("dithered") longitudinally in the space domain. In an approximation regime that our experiments show to be physically realistic, the ratio of the first two significant fourier amplitudes is proportional to the ratio of the focus error to the dither amplitude. Since the illuminatlon, the reflectance, and most technical noise sources affect all fourler amplitudes in an equal multiplicative fashion, the fourler amplitude ratio is a robust measure of the focus error to dither amplitude ratio. The constants needed to calculate absolute range images are the focal length of the lens, the sensor's mean position, and the dither amlpiitude. Experiments using a 50 mm W1.5 camera lens, a pinhole object, and a single detector dithered by an audio speaker demonstrate real-time range resolution of approxlmately 0.5 mun at a range of 350mm. Modelling lndlcatrs that the method, implemented with a sensor array, Is also applicable to extended objects. Plans for extending the experiments to real scenes are discussed.

Measurement Technology and Intelligent Instruments, Sep 22, 1993

We present a novel concept, vector restoration, for motion compensated predictive coding of video... more We present a novel concept, vector restoration, for motion compensated predictive coding of video. Conventional predictive coders generate predictions of the input signal and encode the residual signal. Here, the predicted images are operated upon directly with the goal of restoring the original images at the decoder. The predicted images are processed in a piecewise manner using restoration functions chosen from a codebook. Compression is achieved by transmitting only an index of the chosen restoration function for each image region. We describe the manner in which the restoration functions are generated and chosen. Vector restoration is shown to outperform residual vector quantization and transform-based coders. This superiority is due to vector restoration's ability to adaptively exploit the non-trivial correlation between the predicted and residual images.

The FAA Aging Aircraft Research Program is supporting the development of a robotic mobile nondest... more The FAA Aging Aircraft Research Program is supporting the development of a robotic mobile nondestructive inspection (NDI) instrument deployment tool at Carnegie Mellon University (CMU) with the active participation of USAir. The program has spawned several new relationships and entities: an alliance with an ARPA-funded research program at CMU having the capability to add 3D-stereoscopic enhanced visual inspection capability, a start-up company organized to commercialize the combined technologies, and State of Pennsylvania funding to foster this commercialization. As a result of these activities and connections the civilian sector appears to be ahead of the military sector in important aspects of automation for deployment of aircraft inspection equipment. A partnership between the university researchers, the airline operator, the start-up company, and the state government is thus emerging as the likely agent for transfer of the civilian-developed technology to the military sector.