The ability to identify and quantify changes in the microstructure of metal alloys is valuable in metal cutting and shaping applications. For example, certain metals, after being cryogenically and electrically treated, have shown large increases in their tool life when used in manufacturing cutting and shaping processes. However, the mechanisms of microstructure changes in alloys under various treatments, which cause them to behave differently, are not yet fully understood. The changes are currently evaluated in a semi-quantitative manner by visual inspection of images of the microstructure. This research applies pattern recognition technology to quantitatively measure the changes in microstructure and to validate the initial assertion of increased tool life under certain treatments. Heterogeneous images of aluminum and tungsten carbide of various categories were analyzed using a process including background correction, adaptive thresholding, edge detection and other algorithms for automated analysis of microstructures. The algorithms are robust across a variety of operating conditions. This research not only facilitates better understanding of the effects of electric and cryogenic treatment of these materials, but also their impact on tooling and metal-cutting processes. Future work will focus on the application of statistical methods for analyzing images of more complex metal alloys.
The inspection of sidewall thickness provides important information about the production processes for glass container manufacture. By monitoring the thickness profile around the perimeter of bottles in real-time, the manufacturing process can be altered to produce higher quality products. This also provides the ability to identify and remove defective products. In order to improve the speed and accuracy of inspections, a new non-contact method for acquiring thickness profiles of glass bottles that employs optical and machine vision techniques has been developed and tested.
One of the fundamental laws of optics, Snell's Law, is the basic concept upon which the inspection technique relies. The thickness of a flat plane of transparent material can be determined from Snell’s Law with a single beam of light that passes through the medium, reflects off the secondary surface, and travels back to the initial surface and passes through it. Based upon this principle, a new non-contact glass thickness measurement technique has been developed and it has demonstrated good accuracy.
The detection of shot boundaries in video sequences is an important task for generating indexed video databases. This paper provides a comprehensive quantitative comparison of the metrics, which have been applied to shot boundary detection. We will additionally consider several standardized statistical tests, which have not been applied to this problem, and three new metrics. A mathematical framework for quantitatively comparing metrics is supplied. Also included, are experimental results based on a video database containing 39,000 frames.
A fuzzy logic system for the detection of shot boundaries in video sequences is presented. It integrates multiple metrics and knowledge of editing procedures to detect shot boundaries. Furthermore, the system is capable of classifying the editing process employed to create the shot boundary into one of the following categories: abrupt cut, fade-in, fade-out, or dissolve.
Pattern models for the analysis, visualization, and compression of experimental 2-D flow imagery are developed. Linear and nonlinear models are presented, both of which use the linear phase portrait as a basic building block. These techniques require orientation field computation, critical point detection, and estimation of the associated phase portraits as preliminary analysis steps. In the linear case flows are modeled as a superposition of phase portraits, where their strengths are determined from the orientation field. This works well for flows that exhibit nearly ideal behavior, and a modification is included which is applicable to a wider range of flows. In the nonlinear case flows are modeled by differential equations of Taylor series form. Inclusion of higher order nonlinear terms provides for better modeling of non-ideal flows. The nonlinear coefficients are computed from the estimated linear phase portrait descriptions. The output of these modeling techniques is a compact set of coefficients from which the original flow streamlines are visualized. Finally, the derived models are employed to compress scalar images that exhibit little or gradual variation along the flow streamlines. Compression ratios on the order of 100:1 are achieved.
Inspection of complex electronic packages requires discrimination between the various materials used in such packages. Variations in the appearance of these materials and in the equipment''s illumination complicates the segmentation process. In addition, some materials have similar reflectance and absorption characteristics. As a result, the segmentation process is sensitive to small variations in the illumination settings, photoresponse nonuniformity, and contrast fluctuations. In this paper, we present two techniques that reduce these variations: (1) a new method to calibrate and correct the photoresponse characteristics of optical inspection systems, and (2) a method to automatically correct for contrast variations between the inspected packages. This results in a more repetitive appearance of the used packaging materials, which in turn results in improved segmentation performance. The photoresponse correction procedure, models the output of each photosite as a linear function of input illumination and the parameters of the model are measured. The response is corrected using image processing hardware. Experimental results show that the nonuniformity is corrected to within +/- 1 of the A/D dynamic range which agrees with the error analysis. The contrast adjustment method adjusts the image contrast based on histogram features and is adjusted using vendor and custom developed hardware. The relationship between the two techniques is also discussed.
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