Shape measurement with one fringe pattern recording including a digital master

Rosendahl, Sara; Hällstig, Emil; Gren, Per; Sjödahl, Mikael

doi:10.1364/ao.49.002622

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…Moreover, it is difficult to select a proper position of the laser projector to scan the plane of connectors where pins are located, while maintaining the robustness to the noise introduced by the pins body reflection. As active vision technologies, the phase measurement [14], time-of-flight [15], fringe projection [16] and some complex combinations [17] require a large number of hardware devices as well as high installation demands. Like many traditional visual measurement solutions [18][19][20], especially those for the industrial manufacturing field, the set of customized precision equipment provide a rigorous and simple environment, thereby simplifying the algorithms while reducing the adaptability and flexibility of the method.…”

Section: Related Workmentioning

confidence: 99%

Vision-based adaptive stereo measurement of pins on multi-type electrical connectors

Delong

Kong

2019

Meas. Sci. Technol.

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As a non-contact inspection approach, vision technology usually undertakes the task of positioning, measuring and defect identification in the field of industrial automation. However, traditional visual programs at a high price are often designed for only a single category of products. Furthermore, the quantitative measurement tasks in the industry usually require a rigorous visual environment as well as hardware equipment, which implies a lack of generalization. Hence, it is imperative to establish a robust approach to break the barriers of multi-type product inspection, while reducing both system complexity and costs. This paper proposed an adaptive approach that performs inspections of the pins’ position for multi-type connectors. A joint strategy of deep neural network and pattern matching based on prior knowledge registration is constructed to achieve rapid positioning of sub-elements arranged in the target. Then, a hierarchical extraction method is designed to analyze features with various appearances and improve the anti-interference of vision-based system. The 3D version of the registration algorithm is embedded into the framework to determine abnormal positions of spatial data without reference. The proposed algorithm demonstrates a successful inspection of a total of 33 types of connectors, significant measurement robustness and adaptivity to the target pose, imaging status and feature diversity.

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Section: Related Workmentioning

confidence: 99%

Vision-based adaptive stereo measurement of pins on multi-type electrical connectors

Delong

Kong

2019

Meas. Sci. Technol.

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“…The microscopic fringe projection method, on the contrary, is studied widely and suitable for measuring microstructures whose dimensions are in the order of millimeters and above with the measurement accuracy from a few to tens of microns [ 9 , 10 , 11 ]. It can realize well 3D measurement of microstructures with different surfaces such as a gauge block [ 12 ], ball grid arrays (BGA) [ 13 , 14 ], coins [ 15 , 16 ], a wafer [ 17 ], an earphone diaphragm [ 18 ], and a step master [ 19 ], and can also perform dynamic measurements [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Microscopic Three-Dimensional Measurement Based on Telecentric Stereo and Speckle Projection Methods

Chen

Shi

Liu

et al. 2018

Sensors

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Three-dimensional (3D) measurement of microstructures has become increasingly important, and many microscopic measurement methods have been developed. For the dimension in several millimeters together with the accuracy at sub-pixel or sub-micron level, there is almost no effective measurement method now. Here we present a method combining the microscopic stereo measurement with the digital speckle projection. A microscopy experimental setup mainly composed of two telecentric cameras and an industrial projection module is established and a telecentric binocular stereo reconstruction procedure is carried out. The measurement accuracy has firstly been verified by performing 3D measurements of grid arrays at different locations and cylinder arrays with different height differences. Then two Mitutoyo step masters have been used for further verification. The experimental results show that the proposed method can obtain 3D information of the microstructure with a sub-pixel and even sub-micron measuring accuracy in millimeter scale.

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