Measurement card, measurement system and measurement method using the same
A measurement system includes a camera and a processor. The camera is configured to capture a measurement card image of a measurement card, and the measurement card image includes a number of feature pattern images. The processor is electrically connected to the camera and configured for analyzing the feature pattern images to obtain a feature point coordinate of a feature point of each feature pattern image, and inputting the feature point coordinates into a conversion matrix to obtain a tip coordinate of a tip of the measurement card.
1 . A measurement system, comprising:
a camera configured for capturing a measurement card image of a measurement card, the measurement card comprises a main body and a plurality of feature patterns, wherein the main body has a lateral edge and a tip opposite to the lateral edge, the feature patterns are formed on the main body, and the feature patterns satisfy at least one of the following (1) and (2): (1). there is a first interval between a first-one and a second-one of the feature patterns in a reference axis passing through the lateral edge and the tip, there is a second interval between the second-one and a third-one of the feature patterns in the reference axis, wherein the second interval is different from the first interval; (2). the feature patterns are asymmetrically arranged with respect to the reference axis; the measurement card image comprises a plurality of feature pattern images corresponding to the feature patterns; and
a processor electrically connected to the camera and configured to:
analyze the feature pattern images to obtain a feature point coordinate of a feature point of each of the feature pattern images; and
input the feature point coordinates into a transformation matrix to obtain a tip coordinate of the tip.
2 . The measurement system according to claim 1 , wherein the measurement card image has a background pattern image, and the background pattern image surrounds the feature pattern images; the processor is further configured to:
obtain a region of interest (ROI) of the background pattern image which is mapped to a color coordinate system; and
obtain the feature pattern images of the measurement card image according to the ROL.
3 . The measurement system according to claim 2 , wherein the color coordinate system is a HSV chromaticity coordinate.
4 . The measurement system according to claim 1 , wherein the processor is further configured to:
convert the feature pattern images to a plurality of grayscale feature pattern images.
5 . The measurement system according to claim 1 , wherein each of the feature pattern images is a circle image; the processor is further configured to:
obtain a center coordinate of a center of each of the circle images; and
input the center coordinates into the transformation matrix to obtain the corresponding tip coordinate.
6 . The measurement system according to claim 1 , wherein the feature pattern images comprises a plurality of inner circle images and a plurality of outer circle images; the processor is further configured to:
obtain a center coordinate of an inner circle of each of the inner circle images;
obtain a center coordinate of an outer circle of each of the outer circle images; and
input the center coordinates of the inner circles and the center coordinates of the outer circles into the transformation matrix to obtain the corresponding tip coordinate.
7 . The measurement system according to claim 1 , wherein the measurement card image refers to a first coordinate system, the tip coordinate refers to a second coordinate system, and the transformation matrix is a transformation relationship of the first coordinate system to the second coordinate system.
8 . A measurement method, comprising:
capturing a measurement card image of a measurement card by a camera, wherein the measurement card comprises a main body and a plurality of feature patterns, wherein the main body has a lateral edge and a tip opposite to the lateral edge, the feature patterns are formed on the main body, and the feature patterns satisfy at least one of the following (1) and (2): (1). there is a first interval between a first-one and a second-one of the feature patterns in a reference axis passing through the lateral edge and the tip, there is a second interval between the second-one and a third-one of the feature patterns in the reference axis, wherein the second interval is different from the first interval; (2). the feature patterns are asymmetrically arranged with respect to the reference axis; the measurement card image comprises a plurality of feature pattern images corresponding to the feature patterns;
analyzing the feature pattern images to obtain a feature point coordinate of a feature point of each of the feature pattern images; and
inputting the feature point coordinates into a transformation matrix to obtain a tip coordinate of the tip.
9 . The measurement method according to claim 8 , wherein the measurement card image has a background pattern image, and the background pattern image surrounds the feature pattern images; the measurement method further comprising:
obtaining a ROI of the background pattern image which is mapped to a color coordinate system; and
obtaining the feature pattern images of the measurement card image according to the ROL.
10 . The measurement method according to claim 9 , wherein the color coordinate system is a HSV chromaticity coordinate.
11 . The measurement method according to claim 8 , further comprising:
after obtaining the feature pattern images of the measurement card image according to the ROI, convert the feature pattern images to a plurality of grayscale feature pattern images.
12 . The measurement method according to claim 8 , wherein each of the feature pattern images is a circle image, and each of the feature points is a center of the corresponding circle image; analyzing the feature pattern images to obtain the feature point coordinate of the feature point of each of the feature pattern images further comprising:
obtaining a center coordinate of a center of each of the circle images;
wherein inputting the feature point coordinates into the transformation matrix to obtain the tip coordinate of the tip comprises:
inputting the center coordinates into the transformation matrix to obtain the corresponding tip coordinate.
13 . The measurement method according to claim 8 , wherein the feature pattern images comprises a plurality of inner circle images and a plurality of outer circle images; analyzing the feature pattern images to obtain the feature point coordinate of the feature point of each of the feature pattern images further comprising:
obtaining a center coordinate of an inner circle of each of the inner circle images; and
obtaining a center coordinate of an outer circle of each of the outer circle images;
wherein inputting the feature point coordinates into the transformation matrix to obtain the tip coordinate of the tip comprises:
inputting the center coordinates of the inner circles and the center coordinates of the outer circles into the transformation matrix to obtain the corresponding tip coordinate.