A computing device reads a reference image and a real-time of a printed circuit board (PCB), determines feature points and feature information of the feature points in the reference image; and creates two 1×N matrices based on the feature points. Furthermore, a mapping matrix is determined based on the two 1×N matrices. The device determines matching points in the real-time image based on coordinates of base points in the reference image and the mapping matrix, determines a matching region the real-time image based on the matching points, and determines an angle between the matching region and an X-axis of a coordinate system. If the angle does not equal zero, the device determines that the real-time is tilted, and corrects the real-time image to obtain a corrected image by taking a center of the real-time image as a turning pivot to rotate the real-time image until the angle equals zero.