3D human scan experiment analysis

Experimental results
1, calibration
In order to determine the accuracy of the device, a three-dimensional point of the angular point of the column (radius 24 Em), height 180 cm) and the cylindrical face is designed. The calibration target of the coordinate value is shown in Figure 6. The height in the vertical direction of each color block on the cylinder is the same, and the arc length in the horizontal direction is different, so that the coordinate values of the respective angular points on the cylinder are nonlinear relationships, thus improving the accuracy of the calibration. At least 30 standard timing points are selected for the real camera and virtual cameras.

 

 

 

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According to each set The camera is analyzed by the calculated value of the same calibration point in the empty question. For example: 2 cameras captured the same point P in the space on the calibration target. The three-dimensional coordinates obtained by the image conversion of the next camera and the other camera were recorded as P ', and p ".

 

The scanning system of this paper selects 31 identical calibration points, the average error of the calibration point is 2.03 mm, and the standard deviation is 0.86 mm.
2, the speed and accuracy of the laser light band center extraction

The speed and accuracy of the laser light band can directly affect the performance of the scanning system, so in research and comparing several common laser light extraction algorithms ( After the image refinement method, curve is legal, the centric method, the HESSIAN matrix method, etc. Noise interference on the light band, re-use the Dapuna to acquire the threshold of the optical strip image. Based on this threshold, it is based on the list to meet this threshold requirements, and the primary value point is the optical belt center point and The light intensity threshold T of this column is calculated. Assume the position of the maximum point is the first Y ... line of the column, the threshold is T, and then at the maximum value point, each of the pixels of the threshold is selected, usually 10 ~ 15. The gravity operation of the curve can then be performed in formula (14).

, (z, y.) Is a gradation value of the corresponding pixel point, (X ., Y. Coordinate for the center point of the foundable light.

Also because the image light collected by the CCD camera complies with the Gaussian distribution, the HESSIAN matrix method can be used. Calculate the normal direction of the optical band in the image And find the extreme point in the normal direction, thus obtaining sub-pixel positions of the optical belt center line. This

The coordinates of the resulting optical belt center points are more accurate.

3, human scanning

Selecting a female high 165 cm of the L position for scanning experiments. The scanner is standing in the real camera. The front surface data of the human body is taken directly from the real camera, and the 3L 286 data points are collected, and the standard error is 0.73 mm. The spacing of 2 adjacent points in the horizontal direction does not exceed 3.1 mm. The front data point cloud map of the human body is shown in Figure 7.

The left and right sides of the back surface of the human body is not directly taken directly, which is equivalent to the camera to take the target from the left and right sides of the plane. The resulting image pixel accuracy is lower than the front, and each side is probably obtaining the human surface 16 784 to 18 372 points. The standard error is 0.92 ~ 1.08 mm, and the spacing of adjacent two points in the horizontal direction is not. More than 3.9 mm. Figure 8 shows the backpoint cloud of the human body after the back of the left and right sides of the body. Table L shows the current main commercial three-dimensional body scanner consumption and accuracy. Compared with the current commercial three-dimensional scanning system, the scanning system of

is significantly shortened than that of the scan time, but the scan time is significantly shortened. Therefore, the scanning system accuracy of this paper can meet the requirements of related work such as clothing design and platelets, and can be used for three-dimensional clothing design and virtual stereo cut.

 

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