Beam limiting device edge obtaining method and device and X-ray photographic equipment

The invention discloses a beam limiting device edge obtaining method and device and X-ray photographic equipment. The beam limiting device edge obtaining method is used for obtaining beam limiting device edges in an image. The beam limiting device edge obtaining method comprises the steps that straight edges in the image are detected based on a beam limiting device edge detection method; when the length of the longest straight edge is greater than or equal to a first threshold value, the longest straight edge is determined as the beam limiting device edge; a weak edge in a gradient image of the image is detected to obtain a first image; a first straight edge parallel to the longest straight edge is obtained; the first straight edge with the length greater than or equal to a second threshold value but smaller than or equal to a third threshold value is determined as the beam limiting device edge; a second straight edge with the length greater than or equal to a fourth threshold value but smaller than or equal to a fifth threshold value is determined as the beam limiting device edge, wherein the second straight edge is located in the first image and is perpendicular to the longest straight edge. Through the technical scheme, the detection accuracy of the beam limiting device edges is improved, and the complexity of the beam limiting device edges obtained according to the method is low.