Characterization of scannerless ladar

Monson, Todd C.; Grantham, J. W.; Childress, Steve; Sackos, John T.; Nellums, Robert O.; Lebien, Steve M.

doi:10.1117/12.351362

Cited by 14 publications

(8 citation statements)

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“…4R 1 a1 = ATAN( Il + '2 14) (8) This 4-point algorithm is particularly efficient, being two differences and an ARCTAN function. The algorithm may be faster if the trigonometric function is replaced by a look-up A limitation of heterodyne TOF detection is the periodic nature of the range data.…”

Section: Range Tof Algorithmmentioning

confidence: 98%

Miniature high-resolution laser radar operating at video rates

Smithpeter¹,

Nellums²,

M³

et al. 2000

SPIE Proceedings

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ABSTIGiCTWe are developing a laser radar to meet the needs of NASA for a 5-lb, 150 in3 image sensor with a pixel range accuracy of 0.1 -inch. NASA applications include structural dynamics measurements, navigation guidance in rendezvous and proximity operations, and space vehicle inspection. The sensor is based on the scannerless range imager architecture developed at Sandia. This architecture modulates laser floodlight illumination and a focal plane receiver to phase encode the laser time of flight (TOF) for each pixel. We believe this approach has significant advantages over architectures directly measuring TOF including high data rate, reduced detector bandwidth, and conventional FPA detection. A limitation of the phase detection technique is its periodic nature, which provides relative range information over a finite ambiguity interval. To extend the operating interval while maintaining a given range resolution, a LADAR sensor using dual modulation frequencies has been developed. This sensor also extends the relative range information to absolute range by calibrating a gating function on the receiver to the TOF. The modulation frequency values can be scaled to meet the resolution and range interval requirements of different applications. Results from the miniature NASA sensor illustrate the advantages of the dualfrequency operation and the ability to provide the range images of 640 by 480 pixels at 30 fi-ames per second.

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Section: Range Tof Algorithmmentioning

confidence: 98%

Miniature high-resolution laser radar operating at video rates

Smithpeter¹,

Nellums²,

M³

et al. 2000

SPIE Proceedings

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“…Many current autonomous ground vehicles use to find out their ways to go. This active space measurement technique requires the fast laser pulse scanning [1][2][3][4][5][6][7] .…”

Section: Introductionmentioning

confidence: 99%

Space imaging optical guidance for ground vehicle

et al. 2007

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We have developed the Space Imaging Optical Guidance for Ground Vehicle that uses the narrow field view of the Space Imaging Measurement System based on the fixed lens and fast moving detector to detect the objects to be evaded and the wide field view of the visible optical fine camera to set the drive path.In particular the angel between the optical axis of the narrow field view and the roadside object is very small. Therefore we considered the image segmentation processing of the narrow field view. This provides the accurate detection of the roadside object and its distance.To confirm the guidance ability of the Space Imaging Optical Guidance for Ground Vehicle we tested the Space Imaging Optical Guidance for Ground Vehicle on the road. The road has the object on the road and the roadside wall. The Space Imaging Optical Guidance for Ground Vehicle can detect the object and the surface of the wall and its distance.

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“…External shuttering systems use a standard CCD or CMOS image sensor coupled to an external image modulation device [7][8][9][10][11][12][13][14][15] . This external modulation device is typically an Image Intensifier simply because it is one of the few technologies that is capable of modulating an image at 100 MHz.…”

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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Characterization of scannerless ladar

Cited by 14 publications

References 0 publications

Miniature high-resolution laser radar operating at video rates

Miniature high-resolution laser radar operating at video rates

Space imaging optical guidance for ground vehicle

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

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