阅读说明：本技术 一种激光光斑尺寸边缘轮廓线绘制方法 (Laser spot size edge contour line drawing method ) 是由 张思博 车英 王菲 刘长青 李玉瑶 黄一芮 赵亚超 陈燨 底才翔 田明 于 2019-09-18 设计创作，主要内容包括：本发明公开了一种激光光斑尺寸边缘轮廓线绘制方法,先求取激光光斑质心位置并以质心为坐标原点O’建立直角坐标系,通过求解θ<Sub>i</Sub>角度对应各有效像元(x’<Sub>a</Sub>,y’<Sub>b</Sub>)到过坐标原点O’且角度为90°+θ<Sub>i</Sub>直线的位移d<Sub>iab</Sub>及激光光斑尺寸ω<Sub>θi</Sub>,从而获得θ<Sub>i</Sub>角度方向对应的激光光斑尺寸边缘轮廓点的坐标(x<Sub>θi</Sub>,y<Sub>θi</Sub>),通过连接不同θ<Sub>i</Sub>角度方向的激光光斑尺寸边缘轮廓点,从而绘制出一个激光光斑尺寸边缘轮廓线。本发明通过连接各个边缘轮廓点绘制出光斑尺寸边缘轮廓曲线,直观地反映出激光光斑尺寸的几何形状。(The invention discloses a method for drawing a laser spot size edge contour line, which comprises the steps of firstly obtaining the centroid position of a laser spot, establishing a rectangular coordinate system by taking the centroid as the origin of coordinates O', and solving theta i The angle corresponds to each effective pixel (x' a ，y' b ) To the origin of coordinates O' and at an angle of 90 ° + θ i Linear displacement d iab And laser spot size omega θi To thereby obtain theta i coordinate (x) of edge contour point of laser spot size corresponding to angle direction θi ，y θi ) By connecting different theta i and (3) drawing a laser spot size edge contour line by using the laser spot size edge contour points in the angle direction. The invention draws a spot size edge contour curve by connecting each edge contour point, and visually reflects the geometric shape of the laser spot size.)

1. A laser spot size edge line drawing method is characterized by comprising the following steps:

Step one, obtaining a laser spot image with width W (pixel number) and length H (pixel number); the image has no background noise and has no saturated pixel; establishing a rectangular coordinate system xOy by taking the upper left corner of the image as an origin O, the horizontal right direction as the positive direction of an x axis and the vertical downward direction as the positive direction of a y axis; extracting coordinate values (x) of each pixel element in the image_a，y_b) And corresponding light intensity value I (x)_a，y_b)；

Step two, calculating by using a formula (1) and a formula (2)Coordinate position (x) of laser spot centroid O_c，y_c)；

Taking the centroid O 'as a coordinate origin, selecting a horizontal rightward direction as an x' axis positive direction and a vertical upward direction as a y 'axis positive direction, and establishing a rectangular coordinate system x' O 'y';

Step four, calculating the coordinate (x ') of each pixel under the rectangular coordinate system x ' O ' y ' by using a formula (3) '_a，y'_b) Extracting light intensity value I (x ') corresponding to each pixel element'_a，y'_b)；

Step five, under a rectangular coordinate system x 'O' y ', setting a passing coordinate origin O' and an angle of 90 degrees + theta_iThe equation of the straight line of (1) is:

k_ix'+y'＝0 (4)

Sixthly, in the rectangular coordinate system x ' O ' y ', the formula (5) is used for solving theta_iangle corresponding effective pixel (x'_a，y'_b) Displacement d to the line of equation (4)_iabThe angle theta is obtained by using the relationship between the laser spot size and the second moment of the light intensity shown in the formula (6)_iLaser spot size omega in direction_θiI.e. is theta_iEdge contour point P of laser spot size in direction_θidistance to centroid O';

Theta in the sixth step_iThe selection method of the effective pixel corresponding to the angle comprises the following steps:

When theta is_id is taken when the angle is greater than or equal to 0 DEG and less than or equal to 90 DEG or greater than 270 DEG and less than or equal to 360 DEG_iab>The pixel of 0 is taken as an effective pixel;

when theta is_iWhen the angle is more than 90 degrees and less than or equal to 270 degrees, take d_iab<The pixel of 0 is taken as an effective pixel;

step seven, solving theta by using a formula (7) and a formula (8)_iCoordinate (x) of edge contour point of laser spot size corresponding to angle direction_θi，y_θi)；

x_θi＝ω_θi*cosθi (7)

y_θi＝ω_θi*sinθi (8)

Step eight, repeating the step five to the step seven to obtain different theta_ithe coordinate (x) of the edge contour point of the laser spot size corresponding to the value_θi，y_θi)；

And step nine, sequentially connecting the laser spot size edge contour points (x) corresponding to the laser spot sizes from i-1 to i-n (n is an integer larger than 3)_θi，y_θi) And are connected in parallel (x)_θ1，y_θ1) And (x)_θn，y_θn) Thereby drawing a laser spot size edge contour line.

2. The method for drawing the laser spot size edge line as claimed in claim 1, wherein: in the sixth step, the equation (5) is used to obtain theta_iAngle corresponding effective pixel (x'_a，y'_b) Displacement d to the line of equation (4)_iab。

3. The method for drawing the laser spot size edge line as claimed in claim 1, wherein: theta in the sixth step_iThe method for selecting the angle-corresponding effective pixel comprises the following steps:

When theta is_id is taken when the angle is greater than or equal to 0 DEG and less than or equal to 90 DEG or greater than 270 DEG and less than or equal to 360 DEG_iab>The pixel of 0 is taken as an effective pixel;

When theta is_iWhen the angle is more than 90 degrees and less than or equal to 270 degrees, take d_iab<The pixel of 0 is taken as an effective pixel.

4. The method for drawing the laser spot size edge line as claimed in claim 1, wherein: in the seventh step, theta is obtained by using the formula (7) and the formula (8)_iCoordinate (x) of edge contour point of laser spot size corresponding to angle direction_θi，y_θi)。

Technical Field

The invention relates to a method for drawing laser spot size edge contour lines, and belongs to the technical field of lasers.

Background

In the design, manufacture and application of the laser, the laser spot parameters in the vertical axis section are important indexes for evaluating the quality of the laser spot, and the geometric shape of the laser spot can be reflected visually by the laser spot size edge contour line. At present, the method for drawing the laser spot size edge contour line mainly has two forms: one is to extract by taking 1/e2 of the maximum value of the light intensity of the light spot as a threshold value, and taking the light spot size edge line larger than the threshold value as a light spot size edge profile; and the other method is to adopt a light intensity second moment method to calculate the spot size in the X direction or in the X direction and the Y direction simultaneously, and further carry out circle fitting or ellipse fitting on the edge contour of the spot size. Since the method of calculating the spot by 1/e2 cannot satisfy ABCD law, the second moment method is definitely adopted as the recommended spot size solving method by the international organization for standardization (ISO) in the ISO11146 document. Furthermore, the spot in the transaxial cross-section of the laser output beam is not always circular or symmetrical about the X and Y directions, and therefore, the edge profile of the laser spot size cannot be objectively and truly reflected using a circle fit or an ellipse fit.

disclosure of Invention

Aiming at the defects of the existing spot size edge contour line drawing method, the invention aims to provide a laser spot size edge contour line drawing method, which solves the spot size edge contour line position in any angle direction of a laser spot image by a light intensity secondary moment method, connects each edge contour point to obtain a spot size edge contour line and scientifically and comprehensively reflects the spatial characteristics of a laser spot.

As shown in fig. 1, the method for drawing the laser spot size edge contour line provided by the invention comprises the following steps:

Step one, obtaining a width W (pixel number) and a length H (image)Element number) of laser spot images; the image has no background noise and has no saturated pixel; establishing a rectangular coordinate system xOy by taking the upper left corner of the image as an origin O, the horizontal right direction as the positive direction of an x axis and the vertical downward direction as the positive direction of a y axis; extracting coordinate values (x) of each pixel element in the image_a，y_b) And corresponding light intensity value I (x)_a，y_b)；

Step two, calculating the coordinate position (x) of the laser spot centroid O' by using the formula (1) and the formula (2)_c，y_c)；

taking the centroid O 'as a coordinate origin, selecting a horizontal rightward direction as an x' axis positive direction and a vertical upward direction as a y 'axis positive direction, and establishing a rectangular coordinate system x' O 'y';

step four, calculating the coordinate (x ') of each pixel under the rectangular coordinate system x ' O ' y ' by using a formula (3) '_a，y'_b) Extracting light intensity value I (x ') corresponding to each pixel element'_a，y'_b)；

Step five, under a rectangular coordinate system x 'O' y ', setting a passing coordinate origin O' and an angle of 90 degrees + theta_ithe equation of the straight line of (1) is:

k_ix'+y'＝0 (4)

Sixthly, in the rectangular coordinate system x ' O ' y ', the formula (5) is used for solving theta_iAngle corresponding effective pixel (x'_a，y'_b) Displacement d to the line of equation (4)_iabThe angle theta is obtained by using the relationship between the laser spot size and the second moment of the light intensity shown in the formula (6)_iLaser spot size in directionω_θiI.e. is theta_iEdge contour point P of laser spot size in direction_θidistance to centroid O';

Theta in the sixth step_iThe selection method of the effective pixel corresponding to the angle comprises the following steps:

When theta is_iWhen the angle is greater than or equal to 0 ° and less than or equal to 90 ° or greater than 270 ° and less than or equal to 360 °, d is taken as shown in fig. 2_iab>The pixel of 0 is taken as an effective pixel;

When theta is_iWhen the angle is larger than 90 degrees and less than or equal to 270 degrees, as shown in figure 3, take d_iab<The pixel of 0 is taken as an effective pixel;

Step seven, solving theta by using a formula (7) and a formula (8)_iCoordinate (x) of edge contour point of laser spot size corresponding to angle direction_θi，y_θi)；

x_θi＝ω_θi*cosθi (7)

y_θi＝ω_θi*sinθi (8)

Step eight, repeating the step five to the step seven to obtain different theta_iThe coordinate (x) of the edge contour point of the laser spot size corresponding to the value_θi，y_θi)；

And step nine, sequentially connecting the edge contour points (x) of the laser spot sizes corresponding to the laser spot sizes from i-1 to i-n (n is preferably an integer greater than 3)_θi，y_θi) And are connected in parallel (x)_θ1，y_θ1) And (x)_θn，y_θn) Thereby drawing a laser spot size edge contour line.

Has the advantages that: according to the invention, on the basis of solving the position of the spot size edge contour point in any angle direction of the laser spot image, a spot size edge contour curve is drawn by connecting each edge contour point, so that the geometric shape of the laser spot is reflected visually.

Drawings

Fig. 1 is a schematic flow chart of a method for drawing a laser spot size edge contour line.

FIG. 2 is the angle θ_iThe effective points in the range of less than 90 degrees and more than 270 degrees are selected to be a schematic diagram of the area.

FIG. 3 is the angle θ_iand selecting a schematic diagram of the area at the effective point in the range of 90-270 degrees.

Fig. 4 is a schematic diagram of laser spot size edge profile at i taken as 24.

Detailed Description