Novel optical distance sensor based on MSM technology

Gulden, Peter; Becker, Don; Vossiek, Martin

doi:10.1109/icsens.2002.1036994

Cited by 12 publications

(9 citation statements)

References 14 publications

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“…The basic principle is that each pixel has two charge collection bins, and the sign of the modulation signal determines which bin the charge from the collected photons is directed to [1]. The voltage of each bin is read out independently and converted to an unsigned digital value using a 16-bit ADC.…”

Section: Hardware Descriptionmentioning

confidence: 99%

“…Range imaging combines a conventional 2-D image with the distance of each point from the camera, giving a 3-D image. An increasingly popular technique for capturing 3-D images is to utilize an active illumination source and image sensor to measure the time-of-flight (ToF) of light from the camera system to and from the scene simultaneously for every pixel of the sensor [1][2][3][4][5]. The processing required to extract range data from the raw pixel intensity information requires a number of image frames to be stored and temporally processed.…”

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confidence: 99%

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Efficient FPGA implementation of homodyne-based time-of-flight range imaging

Jongenelen

Bailey

Payne

et al. 2010

J Real-Time Image Proc

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Time-of-flight range imaging systems illuminate a scene with an amplitude-modulated light source, the light is reflected from objects in the scene, and measurement of the phase of the modulation envelope is performed to determine the object's distance. As the image sensor is capable of performing this task for every pixel simultaneously, acquisition of the entire scene can be performed at rapid (video) update rates, making the technology ideal for real-time applications. In this paper we present an efficient real-time FPGA algorithm for determining phase, and hence distance, from the raw image sensor output. The algorithm has been implemented on a range imaging system based on the PMD19k-2 image sensor, with range processing performed in real time by a Stratix III FPGA. The scarcest resource in this implementation is RAM, and an analysis is presented to maximise the efficiency of this resource whilst maintaining acceptable processing accuracy. The algorithm can be extended for processing multiple simultaneous modulation frequencies. An efficient method for combining these results to determine unambiguous range, based on the Chinese remainder theorem, is also presented.Keywords 3D-Imaging Á FPGA Á Time-of-flight Á Range imaging Á Chinese remainder theorem BackgroundA standard image provides only a 2-D representation of a scene. In many applications this provides insufficient data. Range imaging combines a conventional 2-D image with the distance of each point from the camera, giving a 3-D image. An increasingly popular technique for capturing 3-D images is to utilize an active illumination source and image sensor to measure the time-of-flight (ToF) of light from the camera system to and from the scene simultaneously for every pixel of the sensor [1][2][3][4][5]. The processing required to extract range data from the raw pixel intensity information requires a number of image frames to be stored and temporally processed. For real-time applications such as mobile robotics [6,7] or gaming [8] it is desirable for the imaging system itself to process these frames in hardware, thereby reducing the load on the higher level processor.The basic principle of ToF range imaging is that a light signal is transmitted from the camera, and the time it takes to be reflected off the object and return to the camera will be proportional to the distance travelled, d, bywhere t is the time taken and c is the speed of light.Since it is difficult to directly measure the time of flight of a large number of pixels simultaneously, one approach is to amplitude modulate the light source with a sinusoid, and measure the phase shift of the modulation envelope, h. The distance for each pixel can then be calculated by

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Section: Hardware Descriptionmentioning

confidence: 99%

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confidence: 99%

Efficient FPGA implementation of homodyne-based time-of-flight range imaging

Jongenelen

Bailey

Payne

et al. 2010

J Real-Time Image Proc

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“…The prime drawback of these techniques is that the objects can be corrosive. For noncontact measurement, several solutions have been developed which include laser reflection [2,3] and ultrasonic reflection [4,5]. While laser and ultrasonic techniques have the advantage of speed, object reflectivity plays an important role in accurate estimation of distance.…”

Section: Introductionmentioning

confidence: 99%

Distance Measurement of Objects using Stereo Vision

Chowdhury

Gao

Islam

2016

Proceedings of the 9th Hellenic Conference on Artificial Intelligence

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Vision based distance measurement of objects is continues to be a popular research topic in computer and robot vision nowadays. Measuring distance of targets are important for robot navigation, obstacle detection, navigation of autonomous vehicles, surveillance monitoring, person localization and tracking, and many more. In this paper, we propose an efficient approach for distance measurement of objects using stereo vision. The distance is measured from the estimated depth information of the object from its two image sequences (called left and right image pair) captured by a stereo camera. In order to estimate the depth information we employ a fast stereo algorithm. Experimental evaluation proves the efficiency of our proposed approach comparable to other related methods.

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“…Internal shuttering systems utilize a custom designed image sensor that integrates the shuttering or image modulation function into the image sensor itself [1][2][3][4][5][6] . Although this approach allows for small and efficient range imaging systems, they are currently limited in imaging resolution to around 25 k-pixels due to the nature of the image sensor.…”

Section: Introductionmentioning

confidence: 99%

Video-rate or high-precision: a flexible range imaging camera

Dorrington

Cree

Carnegie

et al. 2008

Image Processing: Machine Vision Applications

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A range imaging camera produces an output similar to a digital photograph, but every pixel in the image contains distance information as well as intensity. This is useful for measuring the shape, size and location of objects in a scene, hence is well suited to certain machine vision applications.Previously we demonstrated a heterodyne range imaging system operating in a relatively high resolution (512-by-512) pixels and high precision (0.4 mm best case) configuration, but with a slow measurement rate (one every 10 s). Although this high precision range imaging is useful for some applications, the low acquisition speed is limiting in many situations. The system's frame rate and length of acquisition is fully configurable in software, which means the measurement rate can be increased by compromising precision and image resolution.In this paper we demonstrate the flexibility of our range imaging system by showing examples of high precision ranging at slow acquisition speeds and video-rate ranging with reduced ranging precision and image resolution. We also show that the heterodyne approach and the use of more than four samples per beat cycle provides better linearity than the traditional homodyne quadrature detection approach. Finally, we comment on practical issues of frame rate and beat signal frequency selection.

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Novel optical distance sensor based on MSM technology

Cited by 12 publications

References 14 publications

Efficient FPGA implementation of homodyne-based time-of-flight range imaging

Efficient FPGA implementation of homodyne-based time-of-flight range imaging

Distance Measurement of Objects using Stereo Vision

Video-rate or high-precision: a flexible range imaging camera

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