Positioning and measuring system based on flexible feature image scale

A positioning and measuring system, comprising:

• an image capturing device performing image capturing operations on an object:
• a driving mechanism mechanically connected to one or both of the image capturing device and the object to cause a relative movement between the image capturing device and the object;
• and
• a processor, which is electrically connected to the image capturing device and the driving mechanism and performs steps of:
• (a) controlling the image capturing device to capture N portions of the object to generate N images before and after controlling the driving mechanism to cause M relative motions between the object and the image capturing device, where N is a positive integer greater than or equal to 2, M is equal to (N−1), and neighboring two of the N images partially overlap with each other;
• and
• (b) extracting feature points of each of the N images, and respectively performing cross-image feature point matching according to the feature points of every neighboring two of the N images to obtain information of the M relative motions, wherein the feature points correspond to unique surface morphology of the object,
• wherein the processor further performs, before the step (a), steps of:
• (a1) controlling the image capturing device to capture a calibration sheet with a magnification power to obtain a calibration sheet image, wherein the image capturing device captures the calibration sheet and the object with the magnification power;
• and
• (a2) processing the calibration sheet image to obtain a dimension of one pixel, wherein the processor further determines a dimension corresponding to the information of the M relative motions according to the information of the M relative motions and the dimension of the pixel,
• wherein in the step (a1), the processor controls the image capturing device to capture the calibration sheet with multiple focal lengths to obtain multiple focusing images, transforms the focusing images into a frequency domain to obtain multiple spectrograms, selects one of the spectrograms, which has a most obvious signal presented in an intermediate frequency portion, and captures the calibration sheet with the focal length corresponding to the spectrogram to obtain the calibration sheet image.