&lt;title&gt;Calibration of CCD cameras for field and frame capture modes&lt;/title&gt;

Shortis, Mark R.; Snow, W. L.

doi:10.1117/12.227851

Cited by 9 publications

(8 citation statements)

References 5 publications

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“…The first is that the PAL camera recorded in a progressive scan format. The PAL progressive scan captures the entire image simultaneously whereas the interline capture format used by the HD and FHD cameras captures the odd and even lines of the image separately (Shortis and Snow, 1995). The cameras and the object were stationary during the image capture, so image motion displacement between the odd and even lines is not a significant factor.…”

Section: Source Of Variationmentioning

confidence: 99%

Influence of Range, Angle of View, Image Resolution and Image Compression on Underwater Stereo-Video Measurements: High-Definition and Broadcast-Resolution Video Cameras Compared

Harvey¹,

Goetze²,

McLaren³

et al. 2010

mar technol soc j

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An investigation of how increasing the distance and angle to objects of interest affected the measurement accuracy and precision achievable with high-definition and medium-resolution PAL stereo-video systems was conducted. A test was also conducted to determine whether varying the compression of the imagery influenced measurement accuracy and precision. Measurements of five different lengths of PVC pipe (ranging from 51.5 to 3,001 mm) that represented the lengths of reef fishes routinely sampled with stereo-video were made at 1 m intervals out to the maximum visibility (9 m range) over three different angles (90°, 80°and 70°). High-definition stereovideo imagery was compressed at three different bit-rates. The results show that higher definition stereo-video imagery allows objects to be measured more accurately and precisely over greater ranges. When both ends of a target can be clearly seen in high-definition stereo-video imagery, the associated error is approximately 1% of the total length of the object. There was no deleterious effect on accuracy or precision from increasing the angle of view. Lower compression did not result in more accurate and precise length estimates. The configuration of a stereo-video system needs to match the task of a particular survey, as changes in the base separation and angle of convergence will affect the accuracy and precision of measurements. With full highdefinition systems, smaller lengths (<50 mm) of PVC could not be accurately measured at distances greater than 5 m whereas longer lengths (500-3,001 mm) could be measured with acceptable accuracy and precision at 9 m.

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Section: Source Of Variationmentioning

confidence: 99%

Influence of Range, Angle of View, Image Resolution and Image Compression on Underwater Stereo-Video Measurements: High-Definition and Broadcast-Resolution Video Cameras Compared

Harvey¹,

Goetze²,

McLaren³

et al. 2010

mar technol soc j

Self Cite

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show abstract

“…Video cassette tape is the most efficient, widely used and low cost method to record video images. Video tape provides a permanent record and is very economical in terms of cost per image for short sequences of interest from long duration experiments (Snow and Shortis, 1995). Of the available alternatives, Super VHS (S-VHS) has the highest horizontal resolution and bandwidth of off the shelf systems (Lusch, 1988).…”

Section: Recordingmentioning

confidence: 99%

“…The computation of centroids of such target images, if possible at all given the checks which are normally applied to images of circular targets (Shortis et al, 1994), is effectively an averaging of position. The disadvantage of using fields is that target images have less extent in the vertical dimension and the computed centroids are subject to biases in position (Shortis and Snow, 1995). The bias is dependent on both the size and position of the target image and the overall effect from many target images is an increase in the random error for the least squares solution for the resection, intersection or calibration.…”

Section: Calibrationmentioning

confidence: 99%

“…The equipment, methodology and algorithms, such as resection/intersection using pre-calibrated cameras, are well understood and can be adapted to a variety of measurement tasks in aerospace testing. The experience gained with the implementation and use of the technology has led to the development of a mature, general purpose system (Snow and Shortis, 1995). This paper will describe the set-up, data gathering, data processing and data analysis components of the system, address some of the practical and algorithmic issues, and finally present two wind tunnel measurement applications.…”

Section: Introductionmentioning

confidence: 99%

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Videometric Tracking of Wind Tunnel Aerospace Models at Nasa Langley Research Center

Shortis

Snow

1997

The Photogrammetric Record

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Wind tunnel engineers require measurements of position and orientation of aerospace models under test conditions. The measurement technique must be non-contact, non-intrusive and have a high sample rate. Videometric techniques based on multiple, synchronized CCD cameras can supply position and orientation data at 30Hz or 60Hz with acceptable accuracies. This paper describes a data acquisition system designed and implemented at NASA Langley Research Center to capture the position and orientation of free-flight aerospace models. System calibration and data processing techniques are discussed. Two examples of model tests will be described and examples of data output will be presented.

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“…The interlaced video is composed of 2 fields that are captured at different moments in time. 4 The time interval between the generation of the 2 fields is 1/60 th of a second. This small delay will exhibit motion artifacts when both fields are combined and displayed as a static image.…”

Section: A Camerasmentioning

confidence: 99%

Experimental Methods Using Photogrammetric Techniques for Parachute Canopy Shape Measurements

Jones¹,

Downey²,

Lunsford³

et al. 2007

19th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar

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NASA Langley Research Center in partnership with the U.S. Army Natick SoldierCenter has collaborated on the development of a payload instrumentation package to record the physical parameters observed during parachute air drop tests. The instrumentation package records a variety of parameters including canopy shape, suspension line loads, payload 3-axis acceleration, and payload velocity. This report discusses the instrumentation design and development process, as well as the photogrammetric measurement technique used to provide shape measurements. The scaled model tests were conducted in the NASA Glenn Plum Brook Space Propulsion Facility, OH.

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<title>Calibration of CCD cameras for field and frame capture modes</title>

Cited by 9 publications

References 5 publications

Influence of Range, Angle of View, Image Resolution and Image Compression on Underwater Stereo-Video Measurements: High-Definition and Broadcast-Resolution Video Cameras Compared

Influence of Range, Angle of View, Image Resolution and Image Compression on Underwater Stereo-Video Measurements: High-Definition and Broadcast-Resolution Video Cameras Compared

Videometric Tracking of Wind Tunnel Aerospace Models at Nasa Langley Research Center

Experimental Methods Using Photogrammetric Techniques for Parachute Canopy Shape Measurements

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