Disclosure of Invention
The embodiment of the invention provides a Mini/Micro LED small target defect detection method and a classification system, which are used for solving the technical problems that chips are easy to be mistakenly detected to be defects and the accuracy of classifying the chips is low when the defects of a Mini/Micro LED panel are detected.
In view of the above, the first aspect of the present invention provides a method for detecting small target defects of Mini/Micro LEDs, comprising:
acquiring the chip position of a Mini/Micro LED;
performing defect detection and classification on the chip by adopting different algorithms, wherein the chip defect types comprise cold joint, tin frying, leakage fixation, reflection fixation, offset, deflection and polarity inversion;
filling the chip positions of the Mini/Micro LEDs into the color of a Mini/Micro LED panel;
dividing the Mini/Micro LED panel image according to a preset slice proportion, and performing global threshold segmentation on the divided image to obtain panel defects on the divided image;
and splicing the segmented images to obtain the defect position coordinates on the whole Mini/Micro LED panel image.
Optionally, performing defect detection and classification on the chip by using different algorithms respectively includes:
detecting whether the chip has defects of cold joint, tin frying and leakage fixation by using a Yolov5 detection model;
calculating a polarity characteristic vector of the chip, and judging whether the chip has a solid-state defect according to the polarity characteristic vector, wherein if the polarity characteristic vector is 0, the chip is judged to have the solid-state defect;
calculating a distance average value of azimuth feature vectors of the chip and the bonding pad, and judging whether the chip has an offset defect according to the distance average value, wherein if the distance average value is larger than a preset threshold value, the chip is judged to have the offset defect;
calculating the average deviation of the deflection angles of the polar characteristic vector and the (1, 0) vector of the chip, and judging whether the chip has deflection and polarity reversal defects according to the average deviation of the deflection angles, wherein if the average deviation of the deflection angles is larger than a preset angle threshold value, the chip is judged to have deflection defects, and if the average deviation of the deflection angles is larger than 90 degrees, the chip is judged to have polarity reversal defects, and the preset angle threshold value is not larger than 90 degrees.
Optionally, acquiring the chip position of the Mini/Micro LED further comprises:
acquiring a Mini/Micro LED panel image;
and (5) performing position correction on the Mini/Micro LED panel image.
Optionally, acquiring the Mini/Micro LED panel image includes:
and acquiring images of the whole Mini/Micro LED panel according to a Z-shaped running route by using the left upper corner of the Mini/Micro LED panel as a starting position through a camera, and splicing all the images to obtain the images of the Mini/Micro LED panel.
Optionally, performing position correction on the Mini/Micro LED panel image includes:
acquiring a panel upper left reference Mask point coordinate P1 and a panel lower right reference Mask point coordinate P2 in a Mini/Micro LED panel image, and acquiring an upper left reference Mask point coordinate P3 and a panel lower right reference Mask point coordinate P4 in a standard Mini/Micro LED panel;
calculating an included angle formed by P1P2 and P3P4 to obtain a homogeneous transformation matrix;
and carrying out position correction on the Mini/Micro LED panel image according to the homogeneous transformation matrix.
The second aspect of the invention provides a Mini/Micro LED small target defect classification system, comprising:
the chip positioning module is used for acquiring the chip position of the Mini/Micro LED;
the chip defect classification module is used for respectively carrying out defect detection and classification on the chip by adopting different algorithms, wherein the chip defect types comprise cold joint, tin frying, solid leakage, solid inversion, offset, deflection and polarity inversion;
the panel filling module is used for filling the chip positions of the Mini/Micro LEDs into the color of the Mini/Micro LED panel;
the segmentation module is used for segmenting the Mini/Micro LED panel image according to a preset slicing proportion, and performing global threshold segmentation on the segmented image to obtain panel defects on the segmented image;
and the panel defect positioning module is used for splicing the segmented images to obtain the defect position coordinates of the whole Mini/Micro LED panel image.
Optionally, the chip defect classification module is specifically configured to:
detecting whether the chip has defects of cold joint, tin frying and leakage fixation by using a Yolov5 detection model;
calculating a polarity characteristic vector of the chip, and judging whether the chip has a solid-state defect according to the polarity characteristic vector, wherein if the polarity characteristic vector is 0, the chip is judged to have the solid-state defect;
calculating a distance average value of azimuth feature vectors of the chip and the bonding pad, and judging whether the chip has an offset defect according to the distance average value, wherein if the distance average value is larger than a preset threshold value, the chip is judged to have the offset defect;
calculating the average deviation of the deflection angles of the polar characteristic vector and the (1, 0) vector of the chip, and judging whether the chip has deflection and polarity reversal defects according to the average deviation of the deflection angles, wherein if the average deviation of the deflection angles is larger than a preset angle threshold value, the chip is judged to have deflection defects, and if the average deviation of the deflection angles is larger than 90 degrees, the chip is judged to have polarity reversal defects, and the preset angle threshold value is not larger than 90 degrees.
Optionally, a correction module is also included;
the correction module is used for:
acquiring a Mini/Micro LED panel image;
and (5) performing position correction on the Mini/Micro LED panel image.
Optionally, acquiring the Mini/Micro LED panel image includes:
and acquiring images of the whole Mini/Micro LED panel according to a Z-shaped running route by using the left upper corner of the Mini/Micro LED panel as a starting position through a camera, and splicing all the images to obtain the images of the Mini/Micro LED panel.
Optionally, acquiring the Mini/Micro LED panel image includes:
and acquiring images of the whole Mini/Micro LED panel according to a Z-shaped running route by using the left upper corner of the Mini/Micro LED panel as a starting position through a camera, and splicing all the images to obtain the images of the Mini/Micro LED panel.
Optionally, performing position correction on the Mini/Micro LED panel image includes:
acquiring a panel upper left reference Mask point coordinate P1 and a panel lower right reference Mask point coordinate P2 in a Mini/Micro LED panel image, and acquiring an upper left reference Mask point coordinate P3 and a panel lower right reference Mask point coordinate P4 in a standard Mini/Micro LED panel;
calculating an included angle formed by P1P2 and P3P4 to obtain a homogeneous transformation matrix;
and carrying out position correction on the Mini/Micro LED panel image according to the homogeneous transformation matrix.
From the technical scheme, the Mini/Micro LED small target defect detection method provided by the invention has the following advantages:
according to the method for detecting the small target defects of the Mini/Micro LED, after the chip positions of the Mini/Micro LED are positioned, the chips are respectively detected and classified by adopting different algorithms, the chip positions of the Mini/Micro LED are filled with the colors of the Mini/Micro LED panel, the Mini/Micro LED panel image is segmented according to the preset slicing proportion, global threshold segmentation is carried out on the segmented image, the panel defects on the segmented image are obtained, the segmented image is spliced, and the defect position coordinates on the whole Mini/Micro LED panel image are obtained, so that the defect that the chips are mistakenly detected as defects when the panel defects are detected is avoided when the chip defects are accurately detected and classified, and the technical problems that the chips are mistakenly detected as the defects when the chip defects of the Mini/Micro LED panel are detected and the chip defect classification accuracy is lower are solved.
Detailed Description
In order to make the present invention better understood by those skilled in the art, the following description will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
For ease of understanding, referring to fig. 1, an embodiment of a method for detecting small target defects of Mini/Micro LEDs is provided in the present invention, including:
and step 101, acquiring the chip position of the Mini/Micro LED.
After the Mini/Micro LED panel image is obtained, the chip position of the Mini/Micro LED is positioned by a preset positioning algorithm, wherein the chip positioning can be performed by a template matching method with a high detection speed.
In one embodiment, because the resolution of the camera is higher, the field of view of the camera is small, and the whole Mini/Micro LED panel image cannot be acquired at one time, the camera is enabled to acquire images according to a Z-shaped running route by taking the upper left corner of the Mini/Micro LED panel as a starting position and the lower right corner of the Mini/Micro LED panel as an ending position, and then all the images are spliced to obtain the whole Mini/Micro LED panel image. In order to avoid affecting the accuracy of subsequent processing results, the invention also needs to correct the position of the Mini/Micro LED panel image, specifically, as shown in fig. 2, obtain the top left reference Mask point coordinate P1 (X1, Y1) and the bottom right reference Mask point coordinate P2 (X2, Y2) of the panel in the Mini/Micro LED panel image, and obtain the top left reference Mask point coordinate P3 (X3, Y3) and the bottom right reference Mask point coordinate P4 (X4, Y4) in the standard Mini/Micro LED panel, and calculate the included angle θ formed by P1P2 and P3P4 to obtain a homogeneous transformation matrix. The calculation formula of the included angle theta is as follows:
θ=tan -1 (α-β)
where α is the slope of the straight line P1P2, β is the slope of the straight line P3P4, θ is positive and indicates clockwise rotation, and θ is negative and indicates counterclockwise rotation.
The calculation formula of the translation amount is as follows:
where Δx is the x-axis translation and Δy is the y-axis translation.
The homogeneous transformation matrix includes a clockwise rotation matrix R1 and a counterclockwise rotation matrix R2:
and (3) carrying out position correction on the Mini/Micro LED panel image according to the homogeneous transformation matrix, namely enabling the Mini/Micro LED panel image to translate and rotate to be in position through the following steps:
(x y 1)=(m n 1)·R1
or (b)
(x y 1)=(m n 1)·R2
Where (x, y) is the transformed coordinates and (m, n) is the coordinates before transformation.
And 102, respectively detecting and classifying the defects of the chip by adopting different algorithms, wherein the types of the defects of the chip comprise cold joint, tin explosion, solid leakage, solid inversion, offset, deflection and polarity inversion.
The chip defect types include dummy solder, solder bumps, leakage, reverse, offset, deflection, and polarity reversal.
And (5) detecting the defects of cold joint, tin explosion and leakage fixation by using a Yolov5 detection model. The defect detection by using the Yolov5 detection model is the prior art, and will not be described in detail herein.
And calculating the polarity characteristic vector of the chip for the solid-inverse defect, and judging whether the chip has the solid-inverse defect according to the polarity characteristic vector, wherein if the polarity characteristic vector is judged to be 0, the chip is judged to have the solid-inverse defect. For polar components, the polarity direction of the component is generally identified on the component. Wherein, a circular mark is arranged near a certain section of the LED chip and used as a polarity mark. The identified regions may be extracted using conventional image processing operators. Finally, from the extracted chip center coordinates P 0 Point to polar region center coordinate P p The polar feature vector P is obtained 0 P p 。
And calculating a distance average value d of azimuth feature vectors of the chip and the bonding pad for the offset defect, and judging whether the chip has the offset defect according to the distance average value d, wherein if the distance average value d is larger than a preset threshold delta, the chip is judged to have the offset defect. After the coarse positioning of the chip is obtained according to the template matching algorithm, the precise positioning of the identification chip can be obtained by adopting a minimum circumscribed rectangle method. The azimuth feature vector comprises the absolute coordinates P of the 4 corner points and the center point of the minimum circumscribed rectangle on the substrate 1 、P 2 、P 3 、P 4 、P 0 . Finally, the azimuth feature vector of the identification target is marked as V= { P 1 ,P 2 ,P 3 ,P 4 ,P 0 }。
The calculation formula of the distance average d is:
wherein,and->The abscissa and the ordinate of the center point of the chip azimuth feature vectorCoordinates of->And->The abscissa and the ordinate of the center point of the pad azimuth feature vector, respectively.
For deflection and polarity reversal defects, the polarity eigenvector T and the (1, 0) vector T of the chip are calculated 0 Average difference of deflection angles of (2)According to the mean deviation of deflection angles->Judging whether the chip has deflection and polarity reversal defects, wherein if the deflection angle is average difference +.>If the deflection angle is larger than the preset angle threshold value, judging that the chip has deflection defects, and if the deflection angle is equal to or smaller than the preset angle threshold value, judging that the chip has deflection defects>If the angle is larger than 90 degrees, judging that the chip has polarity reversal defects, and the preset angle threshold is not larger than 90 degrees.
Average difference of deflection anglesThe calculation formula of (2) is as follows:
and step 103, filling the chip positions of the Mini/Micro LEDs into the color of the Mini/Micro LED panel.
It should be noted that, since the chip may have an effect on the detection of the panel defect, the chip on the panel is first removed and the panel is filled with the same color. And extracting RGB values of a part of a panel around the chip, performing median calculation on a certain amount of RGB data, and filling the whole chip position according to the median RGB values serving as filling colors.
And 104, dividing the Mini/Micro LED panel image according to a preset slice proportion, and performing global threshold segmentation on the divided image to obtain panel defects on the divided image.
It should be noted that there may be small target defects such as dirt, hair, scratches, etc. on the panel, which are generally smaller than 50 μm, and have a large difference from the characteristics of the panel, and the panel may be locally thresholded to find out defects on the panel in consideration of the problems such as uneven lighting and shadows on the panel. Specifically, the image is segmented according to a certain slice proportion, and global threshold segmentation is carried out on the segmented image to obtain defects on the panel in each segmented image.
And 105, splicing the segmented images to obtain the defect position coordinates on the whole Mini/Micro LED panel image.
It should be noted that, after all the divided images are spliced together and the defective pixel points on the divided images are transformed, the defective coordinates on the complete image can be obtained, and the defective pixel point transformation formula is as follows:
wherein, (P' x ,P′ y ) Sitting for pixels on a complete imageLabel (P) x ,P y ) For pixel coordinates on slice images, n i Representing the i-th segmented image. n is n x Represents the maximum value of the transverse slice, n y The maximum value of the longitudinal slice is represented, (W, H) the size of the complete panel image, and (W, H) the size of the divided image.
When (when)Or->When it cannot be divided, n x Or n y The number is increased by one, and when the images are spliced, the abscissa of the last divided image in each row is (W-W), the ordinate of the last divided image in each column is (H-H), and the pixel coordinates of the divided images are added on the basis.
According to the method for detecting the small target defects of the Mini/Micro LED, after the chip positions of the Mini/Micro LED are positioned, the chips are respectively detected and classified by adopting different algorithms, the chip positions of the Mini/Micro LED are filled with the colors of the Mini/Micro LED panel, the Mini/Micro LED panel image is segmented according to the preset slicing proportion, global threshold segmentation is carried out on the segmented image, the panel defects on the segmented image are obtained, the segmented image is spliced, and the defect position coordinates on the whole Mini/Micro LED panel image are obtained, so that the defect that the chips are mistakenly detected as defects when the panel defects are detected is avoided when the chip defects are accurately detected and classified, and the technical problems that the chips are mistakenly detected as the defects when the chip defects of the Mini/Micro LED panel are detected and the chip defect classification accuracy is lower are solved.
For ease of understanding, referring to fig. 3, an embodiment of a Mini/Micro LED small target defect classification system is provided in the present invention, including:
the chip positioning module is used for acquiring the chip position of the Mini/Micro LED;
the chip defect classification module is used for respectively carrying out defect detection and classification on the chip by adopting different algorithms, wherein the chip defect types comprise cold joint, tin frying, solid leakage, solid inversion, offset, deflection and polarity inversion;
the panel filling module is used for filling the chip positions of the Mini/Micro LEDs into the color of the Mini/Micro LED panel;
the segmentation module is used for segmenting the Mini/Micro LED panel image according to a preset slicing proportion, and performing global threshold segmentation on the segmented image to obtain panel defects on the segmented image;
and the panel defect positioning module is used for splicing the segmented images to obtain the defect position coordinates of the whole Mini/Micro LED panel image.
The chip defect classification module is specifically used for:
detecting whether the chip has defects of cold joint, tin frying and leakage fixation by using a Yolov5 detection model;
calculating a polarity characteristic vector of the chip, and judging whether the chip has a solid-state defect according to the polarity characteristic vector, wherein if the polarity characteristic vector is 0, the chip is judged to have the solid-state defect;
calculating a distance average value of azimuth feature vectors of the chip and the bonding pad, and judging whether the chip has an offset defect according to the distance average value, wherein if the distance average value is larger than a preset threshold value, the chip is judged to have the offset defect;
calculating the average deviation of the deflection angles of the polar characteristic vector and the (1, 0) vector of the chip, and judging whether the chip has deflection and polarity reversal defects according to the average deviation of the deflection angles, wherein if the average deviation of the deflection angles is larger than a preset angle threshold value, the chip is judged to have deflection defects, and if the average deviation of the deflection angles is larger than 90 degrees, the chip is judged to have polarity reversal defects, and the preset angle threshold value is not larger than 90 degrees.
The system also comprises a correction module;
the correction module is used for:
acquiring a Mini/Micro LED panel image;
and (5) performing position correction on the Mini/Micro LED panel image.
Acquiring a Mini/Micro LED panel image, comprising:
and acquiring images of the whole Mini/Micro LED panel according to a Z-shaped running route by using the left upper corner of the Mini/Micro LED panel as a starting position through a camera, and splicing all the images to obtain the images of the Mini/Micro LED panel.
Performing position correction on the Mini/Micro LED panel image, including:
acquiring a panel upper left reference Mask point coordinate P1 and a panel lower right reference Mask point coordinate P2 in a Mini/Micro LED panel image, and acquiring an upper left reference Mask point coordinate P3 and a panel lower right reference Mask point coordinate P4 in a standard Mini/Micro LED panel;
calculating an included angle formed by P1P2 and P3P4 to obtain a homogeneous transformation matrix;
and carrying out position correction on the Mini/Micro LED panel image according to the homogeneous transformation matrix.
The Mini/Micro LED small target defect classification system provided by the invention is used for executing the Mini/Micro LED small target defect detection method provided by the invention, and the principle is the same as that of the Mini/Micro LED small target defect detection method provided by the invention, and the detailed description is omitted.
The above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.