FLUORESCENT COATING FOR HIGH CONTRAST IMAGE PROCESSING OF POPULATED PCB
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2001-Dec-11
Publishing Venue
Motorola
Related People
Abstract
Characterization of surface mount technology component placement is essential in order to achieve true process control in an automated factory. Para- metric data about component placement accuracies is required in order to provide closed loop feedback about how a particular robot is functioning and to prevent placement defects before the process goes out of control. In order to gather this information a component measurement device is inserted into the factory line after the robots have placed the components.
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MOTOROLA Technical Developments Volume 13 July 1991
FLUORESCENT COATING FOR HIGH CONTRAST
IMAGE PROCESSING OF POPULATED PCB
by Scott Potter
Characterization of surface mount technology component placement is essential in order to achieve true process control in an automated factory. Para- metric data about component placement accuracies is
required in order to provide closed loop feedback about how a particular robot is functioning and to
prevent placement defects before the process goes out of control. In order to gather this information a component measurement device is inserted into the factory line after the robots have placed the components.
One technique used to collect component place- ment data is to use a standard computer vision system which is focused on the populated circuit board and extract a 2-D image of the surface of the board. The main problem with using computer vision is in attaining an image with enough contrast between the circuit board and the components to be characterized. Attempts to use different lighting techniques to increase the contrast are usually not successful due to variations in circuit board and part surfaces. For this reason attempts to use vision systems for in line placement characterization have often failed.
The technique discussed here provides a high
contrast image between the circuit board and com- ponents placed on the board by robots such that a vision system can be used to collect placement data.
This is achieved wit...