Patent ID: 6862365

Claim:
A method for three dimensional inspection of a ball grid array (BGA) lead on a part, the method comprising the steps of: using a single camera to receive an image of the BGA lead; transmitting the image of the BGA lead to a frame grabber; providing fixed optical elements to obtain a side perspective view of the BGA lead; transmitting the side perspective view of the BGA lead to the frame grabber; operating a processor to send a command to the frame grabber to acquire images of pixel values from the camera; processing the pixel values with the processor to calculate a three dimensional position of the BGA lead; determining a lead center location and a lead diameter in pixels and storing the lead center location and lead diameter in memory; converting the pixel values into world locations by using pixel values and parameters determined during calibration wherein the world locations represent physical locations of the BGA lead with respect to world coordinates defined during calibration, wherein a Z height of each lead is calculated in world coordinates in pixel values by combining a location of a center of a BGA lead from a bottom view with a reference point of the same BGA lead from a side perspective view; converting the world coordinates to part values using a rotation, X placement value and Y placement value to define part coordinates for an ideal part where the part values represent physical dimensions of the BGA lead including lead diameter, lead center location in X part and Y part coordinates and lead height in Z world coordinates; and comparing ideal values defined in a part file to calculate deviation values that represent a deviation of the center of the BGA lead from its ideal location.