Optical Scanning for Structural Vibration Measurement

Espinosa, Julián; Pérez, Jorge; Ivorra, Salvador; Mas, David

doi:10.1080/09349847.2010.519137

Cited by 11 publications

(15 citation statements)

References 10 publications

(9 reference statements)

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“…This can be accomplished by attaching a binary target to the object or using saturated objects in the scene as targets. These techniques were successfully used in [10,11]. In those cases, the image borders were clearly located so information about the object trajectory was also obtained.…”

Section: Multilevel Thresholdingmentioning

confidence: 98%

Vibration frequency measurement using a local multithreshold technique

Espinosa¹,

Roig²,

Pérez³

et al. 2013

Opt. Express

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Abstract:In this paper, we demonstrate the use of a video camera for measuring the frequency of small-amplitude vibration movements. The method is based on image acquisition and multilevel thresholding and it only requires a video camera with high enough acquisition rate, not being necessary the use of targets or auxiliary laser beams. Our proposal is accurate and robust. We demonstrate the technique with a pocket camera recording low-resolution videos with AVI-JPEG compression and measuring different objects that vibrate in parallel or perpendicular direction to the optical sensor. Despite the low resolution and the noise, we are able to measure the main vibration modes of a tuning fork, a loudspeaker and a bridge. Results are successfully compared with design parameters and measurements with alternative devices.

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Section: Multilevel Thresholdingmentioning

confidence: 98%

Vibration frequency measurement using a local multithreshold technique

Espinosa¹,

Roig²,

Pérez³

et al. 2013

Opt. Express

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although other systems can be used, the most common approach is through vision systems and image analysis. Unfortunately, and despite their continuous improvement in temporal and spatial resolutions, these devices are still considered as low-resolution systems mainly in those applications concerning video acquisition for assessing dynamic processes [1].…”

Section: Introductionmentioning

confidence: 99%

Realistic limits for subpixel movement detection

2016

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Object tracking with subpixel accuracy is of fundamental importance in many fields since it provides optimal performance at relatively low-cost. Although there are many theoretical proposals that lead to resolution increments of several orders of magnitude, in practice, this resolution is limited by the imaging systems. In this paper we propose and demonstrate through simple numerical models a realistic limit for subpixel accuracy. The final result is that maximum achievable resolution enhancement is connected with the dynamic range of the image, i.e. the detection limit is 1/2^(nr.bits). The results here presented may help to proper design of superresolution experiments in microscopy, surveillance, defense and other fields.

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“…Additionally, a high speed camera (HSC) with 1000 frames per second and spatial resolution of 800x560 pixels was placed 2 m far from the column. Through this high speed camera, the movement of a target placed in the surface of the concrete was registered by means of a new image processing technique specially developed for these experiments [11]. With the camera, the measurement from linear displacement sensor can be checked to be sure that the external structure did not move at all during the impact.…”

Section: Instrumentationmentioning

confidence: 99%

Real size experiments of a car crash against a building column

Ivorra¹,

Irles²,

Mas³

2010

WIT Transactions on the Built Environment

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Several real size car crash experiments have been carried out. In these experiments low velocity impact against a building column has been tested. The experiments have been carried out on a reinforced concrete column with a rectangular section. The test was developed in an external area; therefore, both the compression load and the boundary conditions in the column had to be applied with a special device. However, the use of a real car forced one to adopt some design conditions in this device. Furthermore, to avoid the need of a driver in the car, an inclined plane and a mechanical guiding system was used.In this paper the device, procedures and instrumentation used in these experiments are described. Five experiments were done with this system and their results are presented here.

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Optical Scanning for Structural Vibration Measurement

Cited by 11 publications

References 10 publications

Vibration frequency measurement using a local multithreshold technique

Vibration frequency measurement using a local multithreshold technique

Realistic limits for subpixel movement detection

Real size experiments of a car crash against a building column

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