Asynchronous event‐based high speed vision for microparticle tracking

Ni, Zhenjiang; Pacoret, Cécile; Benosman, Ryad; Ieng, Sio-Hoï; Régnier, Stéphane

doi:10.1111/j.1365-2818.2011.03565.x

Cited by 86 publications

(58 citation statements)

References 21 publications

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“…Its pixels detect scenes' contrast changes rather than absolute grey level values and send their own data as local information independently and asynchronously [14]. The dedicated algorithms are thus frame free and can be operated at high speeds at the order of several kilohertz [15] [16].…”

Section: Introductionmentioning

confidence: 99%

2D high speed force feedback teleoperation of optical tweezers

Pacoret

Benosman

et al. 2013

2013 IEEE International Conference on Robotics and Automation

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The optical trap is a powerful non-contact approach for manipulating micron sized objects. Teleoperation of optical tweezers can be performed by coupling with a haptic interface, which allows an efficient robotic device to control positions and get force feedback. This provides users direct and intuitive microscopic interactions. The major difficulty in order for haptic devices to generate a reliable tactile sensation lies in its high frequency requirement of more than 1 kHz. This paper presents a fast force feedback teleoperation system for optical tweezers that attains this high frequency. The used force sensor is a novel event-based camera that transmits output as a continuous stream of asynchronous temporal events thus enabling high speed event-based visual processing. This new sensor is compared to a conventional frame based one to show advantages of our setup. A complex task of exploiting three dimensional target surface is performed demonstrating the robustness and efficiency of the presented method. This is the first time microspheres are used to touch targets of arbitrary form and color, which may interest broad-reaching biological and physical applications.

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Section: Introductionmentioning

confidence: 99%

2D high speed force feedback teleoperation of optical tweezers

Pacoret

Benosman

et al. 2013

2013 IEEE International Conference on Robotics and Automation

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“…The use of event-based retinas requires the development of time-oriented event-based algorithms, in order to benefit fully from the properties of this new framework [19]. Neural shape coding is a difficult issue as there is almost an infinite number of representations of shapes in the real world.…”

Section: Introductionmentioning

confidence: 99%

“…This paper is based on several previous papers. In [19], DVS was used to develop an event-based Hough transformation to track specifically circles. Hough transformations rely on a voting scheme and maximum detection within the accumulation spaces to identify the location of a shape.…”

Section: Introductionmentioning

confidence: 99%

Asynchronous Event-Based Visual Shape Tracking for Stable Haptic Feedback in Microrobotics

et al. 2012

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Abstract-Micromanipulation systems have recently been receiving increased attention. Tele-operated or automated micromanipulation is a challenging task due to the need for high-frequency position or force feedback to guarantee stability. In addition, the integration of sensors within micromanipulation platforms is complex. Vision is a commonly used solution for sensing; unfortunately the update rate of the frame-based acquisition process of current available cameras can not ensure-at reasonable costs-stable automated or tele-operated control at the microscale level, where low inertia produces highly unreachable dynamic phenomena. This paper presents a novel vision-based microrobotic system combining both an asynchronous Address Event Representation (AER) silicon retina and a conventional frame-based camera. Unlike frame-based cameras, recent artificial retinas transmit their outputs as a continuous stream of asynchronous temporal events, in a manner similar to the output cells of a biological retina, enabling high update rates. This paper introduces an Event-based Iterative Closest Point algorithm to track a microgripper's position at a frequency of 4 kHz. The temporal precision of the asynchronous silicon retina is used to provide a haptic feedback to assist users during manipulation tasks, whereas the frame-based camera is used to retrieve the position of the object that must be manipulated. This paper presents the results of an experiment on tele-operating a sphere of diameter around 50 µm using a piezo-electric gripper in a pick-and-place task.

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“…The first pick-and-place manipulation with 3D haptic feedback using a microgripper is successfully achieved. This work is based on several previous studies on the stability of haptic coupling schemes for applications at microscales [26], on the definition of virtual guides for pick-and-place operation of microspheres based on two atomic force microscopy cantilevers [27], on the use of visual feedback coming from a scanning electron microscope for teleoperation [28] and on the use of dynamic vision sensors [29]. However, it is the first time, to our knowledge, that dynamic vision sensors are used to provide stable haptic feedback to assist users while performing a pick-and-place operation.…”

Section: Introductionmentioning

confidence: 99%

Stable haptic feedback based on a dynamic vision sensor for microrobotics

Bolopion

Agnus

et al. 2012

2012 IEEE/RSJ International Conference on Intelligent Robots and Systems

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Abstract-This work presents a stable vision based haptic feedback for micromanipulation using both an asynchronous Address Event Representation (AER) silicon retina and a conventional frame-based camera. At this scale, most of the grippers used to manipulate objects lack of force sensing. High frequency vision detection thus provides a sound solution to get information about the position of the object and the tool to provide virtual haptic guides. Artificial retinas present high update rates, which enables to address one of the major challenge of haptic feedback teleoperation systems, namely stability. However static objects are not detected. The haptic feedback is thus based on an asynchronous silicon retina to provide a high update rate of moving objects and a framebased camera to retrieve the position of the target object. This approach is validated by pick-and-place of microspheres (diameter: around 50 micrometers) using a piezoelectric microgripper. The displacement of the tool, as well as the opening and closing of the gripper are controlled by the haptic device. Haptic virtual guides are transmitted to users to assist them in the different steps of the pick-and-place task: a virtual stiffness ensures the correct alignment of the tool with respect to the object, a repulsive haptic force enables users to monitor the gripping step, and operators are assisted while picking and placing the object.

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Asynchronous event‐based high speed vision for microparticle tracking

Cited by 86 publications

References 21 publications

2D high speed force feedback teleoperation of optical tweezers

2D high speed force feedback teleoperation of optical tweezers

Asynchronous Event-Based Visual Shape Tracking for Stable Haptic Feedback in Microrobotics

Stable haptic feedback based on a dynamic vision sensor for microrobotics

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