2P1-N-036 Measurement of solder bumps by shape-from-focus using a varifocal mirror(Machine Vision and Visual Inspection,Mega-Integration in Robotics and Mechatronics to Assist Our Daily Lives)

2005 ◽  
Vol 2005 (0) ◽  
pp. 185
Author(s):  
Jun Mitsudo ◽  
Takahiro Fujioka ◽  
Akira Ishii
Keyword(s):  
Machine Vision ◽  
Visual Inspection ◽  
Daily Lives ◽  
Solder Bumps ◽  
Mirror Machine ◽  
Shape From Focus

A Comparison of Orthogonal Transforms in Engineering Computer Vision

1990 ◽  
Vol 204 (5) ◽  
pp. 321-327 ◽  
Author(s):  
G A H Al-Kindi ◽  
R M Baul ◽  
K F Gill
Keyword(s):  
Computer Vision ◽  
Machine Vision ◽  
Visual Inspection ◽  
Computational Time ◽  
Transform Coefficients ◽  
Orthogonal Transforms ◽  
The Impact

A comparison of a number of commonly used orthogonal transforms, when applied to the recognition and visual inspection of engineering components, has been made. The impact on the performance and computational time for the machine vision process due to varying numbers of transform coefficients is assessed.

Shape Measurement of Solder Bumps by Shape-from-Focus Using Varifocal Mirror

2006 ◽  
Vol 18 (6) ◽  
pp. 722-727
Author(s):  
Jun Mitsudo ◽  
◽  
Akira Ishii
Keyword(s):  
Copper Alloy ◽  
Solder Bump ◽  
Optical Axis ◽  
Focal Point ◽  
Shape Measurement ◽  
Depth Range ◽  
Focal Points ◽  
Depth Data ◽  
Solder Bumps ◽  
Shape From Focus

We measured solder bumps on an LSI package board presented for inspection based on the shape from focus. We used a copper-alloy mirror deformed by a piezoelectric actuator as a varifocal mirror to build a motionless yet fast focusing mechanism. The varifocal mirror was at the image focal point of the image-taking lens so that lateral magnification was constant during focusing and orthographic projection was established. A focused plane was shifted along the optical axis with a precision of 1.4μm in a depth range of 1.5mm by driving the varifocal mirror. A magnification of 1.97 was maintained during focusing. Evaluating the curvature of field and removing its effect from the depth data reduced errors. The shape of 208 solder bumps 260-μm high spaced 500μm on the board was measured. The 10mm×10mm board was segmented into partly overlapping 3×4 sections. We captured 101 images in each section with a high-resolution camera at different focal points at 15-μm intervals. The shape of almost the entire upper-hemisphere of a solder bump could be measured. Error in measuring bump heights was less than 12μm.

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