Method for measuring objects in digestive tract based on imaging system

A method for measuring objects in a digestive tract based on an imaging system, comprising:

• simulating an environment in the digestive tract and starting a calibration process of the imaging system;
• said calibration process, comprising
• setting a plurality of calibration points Q′ on a transparent enclosure of the imaging system;
• controlling a photographing unit of the imaging system to photograph and form a calibration image, and recording the calibration point Q′ imaged in the calibration image as an imaging point Q;
• calculating and determining a relationship between a relative angle θ of the calibration point Q′ relative to the optical axis of the photographing unit and a pixel distance Δq′ from the imaging point Q to the center of the calibration image, and recording it as:
• θ=f(Δq′) (1);
• calculating and determining a relationship between a brightness φ of any pixel in the calibration image and a depth distance z from an actual position of the pixel in the simulated digestive tract to a board where the photographing unit is disposed, and recording it as:
• z(x,y)=g(φ(x,y)) (2);
• calculating a relationship between a scale r of any pixel in the calibration image and the depth distance z from the actual position of the pixel in the simulated digestive tract to the board where the photographing unit is disposed, where scale is the actual length represented by unit pixel in the image, and recording it as:
• r=dz (3);
• performing a measurement process after the calibration process is completed;
• said measurement process, comprising
• placing the imaging system in the digestive tract;
• capturing and obtaining a detection image;
• determining a region in the detection image where the transparent enclosure contacts with the digestive tract wall, and recording it as a contact region, and setting at least one reference point P in the contact region, and recording the actual position of the reference point in the digestive tract as a target point P′;
• calculating a pixel distance Δp from the reference point P to the center of the detection image separately, and putting it into equation 1 to obtain a relative angle θ of the target point P′ relative to the optical axis of the photographing unit;
• calculating an actual distance from the target point P′ to the board separately and recording it as depth distance zi;
• obtaining a predicted brightness g−1(zi) of the reference point P in the detection image according to equation 2 and the depth distance zi;
• comparing the predicted brightness g−1(zi) of the reference point P with an actual pixel brightness img(Pi) of the reference point P to obtain a correction factor ki, and recording it as:
• k
• i
• =
• g
• -
• 1
• ⁡
• (
• z
• i
• )
• img
• ⁡
• (
• P
• i
• )
• ;
• (
• 4
• )
• obtaining a mean value k of the correction factors ki of all reference points P;
• calibrating all pixels in the detection image with the mean value k of the correction factors to obtain a depth distance from an actual position of each pixel in the digestive tract to the board, and recording it as depth image z(x, y), where:
• z(x,y)=g(kimg(x,y)) (5);
• calculating a scale r of each pixel in the detection image according to equation 3 and the depth image z(x, y);
• obtaining pixel coordinates Si of each pixel point in the detection image, and calculating the actual two-dimensional coordinates Si′ of each pixel in the detection image by the scale r;
• integrating to obtain actual three-dimensional coordinates (Si′, z(x, y)) of each pixel;
• calculating or measuring a distance between any two pixels in the detection image or the area within any range;
• wherein
• a photographing unit enclosed in the transparent enclosure, placed in between a board and a front end of the transparent enclosure;
• the transparent enclosure is configured to be placed in the digestive tract and form the contact region;
• and the image system comprises one or more computer processors to calibrate and calculate.