Method and system for calculating laser beam spot size

A system for calculating laser beam spot size, wherein the system comprises:

• a camera for collecting a spot image of a laser beam and a corresponding background noise image along an optical axis direction;
• an image pretreating module for conducting pretreatment using a background subtraction method and a threshold method according to the spot image and the background noise image collected to obtain a pretreated spot image;
• and
• an image calculating module for calculating the central position of a laser spot of the pretreated spot image, storing the pixel gray values of the spot image at the central position of the laser spot on a horizontal direction and a vertical direction, then conducting Gaussian curve fitting, calculating variances of Gaussian fitted curves on the horizontal direction and the vertical direction, and obtaining the spot radiuses of the spot image on the horizontal direction and the vertical direction according to the variances calculated.

A method for calculating laser beam spot size, wherein the method comprises:

• collecting a spot image of a laser beam and a corresponding background noise image along an optical axis direction;
• conducting pretreatment using a background subtraction method and a threshold method according to the spot image and the background noise image collected to obtain a pretreated spot image;
• calculating the central position of a laser spot of the pretreated spot image;
• and
• storing the pixel gray values of the spot image at the central position of the laser spot on a horizontal direction and a vertical direction, then conducting Gaussian curve fitting, calculating variances of Gaussian fitted curves on the horizontal direction and the vertical direction, and obtaining the spot radiuses of the spot image on the horizontal direction and the vertical direction according to the variances calculated without either first aligning the center of a diaphragm with the center of the spot image or using a high precision moving device.