 Optical interprogation system for use in constructing flat tension shadow mask CRTS |
| What is claimed is: 1. An apparatus for interrogating at least one CRT workpiece, comprising; a) a ... |
|
| Structured illumination autonomous machine vision system |
| I claim: 1. A method of providing information for automatically determining pathway boundaries for ... |
|
| Solder joint locator |
| Pursuant to the present invention, a method and system is provided for automatically detecting ... |
|
| Curved surface designing method |
| The present invention has been attained to solve the foregoing problems, and an object thereof is ... |
|
| Digital image processing system and method |
| In accordance with one aspect of the present invention, a digital image processing system comprises ... |
|
| System for frontal illumination |
| These and other objects are attained by the invention which provides, in one aspect, a frontal ... |
|
| Apparatus and method for inspection of high component density printed circuit board |
| Accordingly, it is therefore an object of this invention to use a visual spectrum sensor to view a ... |
|
| System and method for efficient computer workstation screen updates |
| The invention is based on the need in collaborative or cooperative processing environments to allow ... |
|
| Double-accumulator implementation of the convolution function |
| The present invention provides a novel approach to high-speed digital processing involving ... |
|
|
Efficient image registration
| Details |
Inventors: Michael, David;
Assignee: Cognex Corporation (Natick, MA)
Primary Examiner: Britton; Howard W.
Assistant Examiner:
Attorney, Agent or Firm: Weinzimmer; Russ
A method and apparatus for efficient registration of a pair of digitized images is provided that obtains a registration metric value based upon a Sum of Absolute Differences registration metric computation for each of a plurality of neighboring-pixel relative displacements, and, for example, iteratively selects a new initial relative displacement from among the plurality of neighboring-pixel relative displacements such that each succeeding new initial relative displacement is associated with a smaller registration metric value, until an initial relative displacement that is associated with a minimum registration metric value is reached. In general, the relative displacement that is associated with the minimum registration metric value is located using a two-dimensional numerical optimization analysis. The invention is especially useful for flaw and defect analysis, such as Golden Template Analysis, third optical inspection, as well as for pair-wise comparison of die images on a semiconductor wafer. |
|
DETAILED DESCRIPTION An efficient registration method and apparatus provides substantial registration of all of the features common to a pair of images to be registered, even when one of the images to be registered is flawed.
The invention features the use of a registration metric based on minimization of the sum of the absolute value of the differences between a first image and a second image to be registered with respect to the first image.
Also employed is an efficient optimization technique, such as a version of gradient descent, wherein a local minimum in a registration metric space is found to the nearest pixel using less computational resources than needed to compute the entire registration metric space.
In a preferred embodiment, registration to sub-pixel accuracy can be obtained using a sub-pixel interpolation technique.
The invention is well-suited for use in flaw and defect detection applications, such as Golden Template Comparisons, pre- and post-process optical inspection, and inspection of arrays of repeated geometrical designs, wherein after registration is performed, a difference image is derived by computing the difference between each pair of corresponding pixels of the registered image pair.
|
| Related patents |
|
|
Automated optical inspection apparatus
This invention provides a method and apparatus for automatically locating the bond of a wire to a lead frame and semiconductor chip or similar device on one machine as ...
|
|
|
Image processing coefficient determination method, image processing coefficient calculation system, image processing system, image processing method, and storage medium
OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram to show one embodiment of the invention. In the figure, numeral 1 is a process operation section, numeral 2 is an ...
|
|
|
Digital image processing
FIG. 1 is an illustration of a typical hardware layout according to an embodiment of the invention. FIG. 2 shows a comparison between a 4-bit grey scale and an 8-bit ...
|
|
|
Pattern recognition apparatus and method
We claim: 1. A pattern recognition system comprising: video camera means for generating a video signal representative of an area being viewed, opaque means located on a ...
|
|
|
Reflector for multiple source lighting fixture
The present invention provides an improvement in lighting fixtures which permits the pattern and intensity of illumination to be adjusted by rotating one of the ...
|
|
|
Two-dimensional object recognition using chain codes, histogram normalization and trellis algorithm
A new system for classifying a two-dimensional object is disclosed. In its broadest aspects, the system includes means for generating a histogram from the object's ...
|
|
|
Image processing method
Accordingly, one object of the present invention is to provide an image processing method in which the amount of processing is significantly reduced, so as to calculate ...
|
|
|
Mark detecting method and apparatus
According to the above-identified proposal, however, the search has to be made while moving the wafer stage in a blind-feeding manner. Therefore, there is a good ...
|
|
|
Method and apparatus for sorting a flow of objects as a function of optical properties of the objects
The object of the invention is to eliminate the drawbacks of the known method. According to the invention, this object is achieved for the method of the type mentioned ...
|
|
|
Optical character recognition system and method
Accordingly, a system and method for optical character recognition are provided which obviate the need for separate magnetic scanner systems and the performance of ...
|
|
|
Image Analysis 
