Nonlinear filter derived from topological image features

Conference · Mon Jan 01 04:00:00 EST 1990

OSTI ID:5562093

Jatko, W B; Hunt, M A; Tobin, K W

A digital machine-inspection system is being developed at Oak Ridge National Laboratory for detecting flaws on printed graphic images. The inspection is based on subtraction of a digitized test image from a reference image to determine the location, number, extent, and contrast of potential flaws. When performing subtractive analysis on the digitized information, two sources of errors in the amplitude of the difference image can develop: (1) spatial misregistration of the reference and test sample or, (2) random fluctuations in the printing process. Variations in printing and registration between samples will generate topological artifacts related to surface structure, which is referred to as edge noise in the difference image. Most feature extraction routines require that the difference image be relatively free of noise to perform properly. A novel algorithm has been developed to filter edge noise from the difference images. The algorithm relies on the a priori assumption that edge noise will be located near locations having a strong intensity gradient in the reference image. The filter is based on the structure of the reference image and is used to attenuate edge features in the difference image. The filtering algorithm, consisting of a geometric transformation, image multiplication, and erosion/dilation, has reduced edge noise by 67% over the unfiltered image and can be implemented using off-the-shelf hardware. 4 refs., 6 figs.

• Research Organization: Oak Ridge National Lab., TN (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5562093
• Report Number(s): CONF-900451-1; ON: DE90008555
• Country of Publication: United States
• Language: English

Related Subjects

440600* -- Optical Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
ACCURACY
ALGORITHMS
CHEMISTRY
COMPARATIVE EVALUATIONS
DEFECTS
DESIGN
DIGITAL SYSTEMS
DOCUMENTATION
ELECTRICAL PROPERTIES
EROSION
ERRORS
EVALUATION
FILTERS
FLUCTUATIONS
FUNCTIONS
GAUSS FUNCTION
ILLUMINANCE
IMAGE PROCESSING
IMPLEMENTATION
INSPECTION
MATHEMATICAL LOGIC
MATHEMATICS
MEASURING METHODS
MORPHOLOGY
NOISE
OPERATION
OPTIMIZATION
PERFORMANCE TESTING
PHYSICAL PROPERTIES
PROCESSING
SAMPLING
STRUCTURAL MODELS
SURFACE PROPERTIES
TESTING
TOPOLOGY
VARIATIONS