External parameter determination method and image processing device

An image processing device, comprising:

• a storage circuit storing a program code;
• and
• a processor coupled to the storage circuit and accessing the program code to:
• obtain a plurality of images taken by a plurality of cameras for a specific pattern;
• find a plurality of feature point combinations in the plurality of images by performing a feature point matching algorithm on the plurality of images;
• determine a slope corresponding to each of the plurality of feature point combinations;
• find a plurality of candidate combinations among the plurality of feature point combinations based on the slope corresponding to each of the plurality of feature point combinations, wherein a slope of each of the plurality of candidate combinations is within a preset range;
• determine at least one external parameter between the plurality of cameras based on the plurality of candidate combinations.