Algorithms for a Fast Confocal Optical Inspection System

Rao, A. Ravishankar; Ramesh, N.; Wu, Frederick Y.; Mandeville, Jon R.; Kerstens, Pieter J. M.

doi:10.1007/978-3-642-58288-2_17

Cited by 3 publications

(3 citation statements)

References 45 publications

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“…Confocal laser scanning microscopy (CLSM) is a relatively new optical tool for noninvasive evaluation of microstructures of foods and other materials. The primary value of the CLSM lies in its ability to make a series of observations (2‐D layered images) within a 3‐D specimen by focusing at different heights of the specimen, in a process called optical slicing (Rao and others 1992). The specimen can be illuminated and imaged through a pinhole to remove out‐of‐focus light, thus producing a clearer image (Kaláb and others 1995).…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Roughness on Retention and Removal of Escherichia coli O157:H7 on Surfaces of Selected Fruits

Wang

Feng

Liang

et al. 2009

Journal of Food Science

134

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This study was undertaken to evaluate the effect of surface roughness on the attachment and removal of Escherichia coli O157:H7 on selected fruit and metal surfaces. A new method to determine surface roughness was developed using confocal laser scanning microscopy (CLSM). A series of 2-D layered images were taken by CLSM optical slicing of the surfaces of Golden Delicious apples, navel oranges, avocadoes, and cantaloupes. The average roughness (R a ) of the fruit surfaces was assessed by reconstructing a series of 2-D images into 3-D images. A cocktail of 5 E. coli O157:H7 strains were spot inoculated onto fruit skin surfaces with different R a . The fruits were then treated with acidic electrolyzed water (AEW), peroxyacetic acid (POAA), and sterilized deionized water. Aluminum stubs with different R a values as a model system were also spot inoculated with E. coli O157:H7 and subjected to a sonication treatment. Test results indicated that there was a positive linear correlation between R a and adhesion rate of E. coli O157:H7, and a negative correlation between R a and the efficacy of inactivation by AEW and POAA, respectively, on fruit surfaces. A linear increase of residual bacteria population with increased surface roughness of aluminum stubs was also observed. The relationship between surface roughness and surface hydrophobicity was negative linear for the aluminum stubs, but was quadratic for the 4 fruits. The environmental scanning electron microscopy images showed that bacteria tended to attach to or be entrapped in the grooves or cavities of fruits, which provided protection to the cells against washing treatments.

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Section: Introductionmentioning

confidence: 99%

Effect of Surface Roughness on Retention and Removal of Escherichia coli O157:H7 on Surfaces of Selected Fruits

Wang

Feng

Liang

et al. 2009

Journal of Food Science

134

View full text Add to dashboard Cite

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“…There have been a few inspection mechanisms proposed for wafer bumps: laser triangulation [5,13,14], confocal microscopy [4,6,7,10,12], and gray-level pattern projection [1,2,3,8,9,11]. However, laser triangulation is of low speed and low resolution, confocal microscopy involves moving parts and has limitation in its operation speed, and gray-level pattern projection has the problems of image brightness saturation and high sensitivity to noise.…”

Section: Introductionmentioning

confidence: 98%

Three-dimensional reconstruction of wafer solder bumps using binary pattern projection

Cheng

Chung

Lam³

et al. 2005

SPIE Proceedings

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As the electronic industry advances rapidly, the shrunk dimension of the device leads to more stringent requirement on process control and quality assurance. For instance, the tiny size of the solder bumps grown on wafers for direct die-todie bonding pose great challenge to the inspection of the bumps' 3D quality. Traditional pattern projection method of recovering 3D is about projecting a light pattern to the inspected surface and imaging the illuminated surface from one or more points of view. However, image saturation and the specular nature of the bump surface are issues. This paper proposes a new 3D reconstruction mechanism for inspecting the surface of such wafer bumps. It is still based upon the light pattern projection framework, but uses the Ronchi pattern a pattern that contrasts with the traditionally used gray level one. With the use of a parallel or point light source in combination with a binary grating, it allows a discrete pattern to be projected onto the inspected surface. As the projected pattern is binary, the image information is binary as well. With such a bright-or-dark world for each image position, the above-mentioned difficult issues are avoided. Preliminary study shows that the mechanism holds promises that existing approaches do not.

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“…A particular challenge is the development of vision techniques for inspecting the 3-D surface of wafer bumps accurately and efficiently. There have been a few noncontact optical shape measurement methods proposed in the literature: laser triangulation, [1][2][3] confocal microscopy, 4,5 sinusoidal pattern projection, 6 and moiré interferometry. 7,8 However, these methods suffer from either low speed or high sensitivity to noise.…”

Section: Introductionmentioning

confidence: 99%

Projection optics design for tilted projection of fringe patterns

et al. 2008

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A challenge in the semiconductor industry is 3-D inspection of the miniaturized solder bumps grown on wafers for direct die-to-die bonding. An inspection mechanism proposed earlier requires the projection of a binary fringe grating to the inspected surface from an inclined angle. For high speed and accuracy of the mechanism, the projection optics has to meet these requirements: ͑1͒ it allows a tilt angle between the inspected surface and the projector's optical axis; ͑2͒ it has a high bandwidth to let high-spatial-frequency harmonics contained in the binary grating pass through the lens and be projected onto the inspected surface properly; ͑3͒ it has a high modulation transfer function; ͑4͒ it has a large field of view; and ͑5͒ it has an adequate depth of field that matches the depth range of the inspected surface. In this paper, we describe a projection optics design, consisting of a fringe grating and several pieces of spherical lens, that addresses the requirements. To reduce the lens aberrations, the grating is laid out with an angle chosen specifically to make the grating, the lens, and the average plane of the inspected surface intersect in the same line. Performance analysis and tolerance analysis are shown to demonstrate the feasibility of the design.

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Algorithms for a Fast Confocal Optical Inspection System

Cited by 3 publications

References 45 publications

Effect of Surface Roughness on Retention and Removal of Escherichia coli O157:H7 on Surfaces of Selected Fruits

Effect of Surface Roughness on Retention and Removal of Escherichia coli O157:H7 on Surfaces of Selected Fruits

Three-dimensional reconstruction of wafer solder bumps using binary pattern projection

Projection optics design for tilted projection of fringe patterns

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