51 results about "Probabilistic hough transform" patented technology

The invention discloses a monocular vision-based gravitational field method accelerometer calibration method, which mainly comprises the following steps of: proposing a plumb bob method to determine the direction of a gravitational field, and then using a plumb line as an initial reference of a rotation angle of a turntable; using a monocular vision system to shoot a rotary table image, and usinga template matching method to determine a rectangular target feature area in the rotary table image; realizing sub-pixel extraction of the characteristic edge of the rectangular target based on a Zernike moment method; extracting a long edge of the rectangular target by using a cumulative probability Hough Transform (PPHT) algorithm, wherein an included angle between the edge and a plumb line is the rotation angle of the rotary table at the current position; the sensitivity of the accelerometer is calculated by using the measured rotation angle, and the gravitational field method accelerometercalibration at any rotation angle can be realized. According to the method, the defects of limited calibration precision and installation error in multi-axis acceleration timing calibration in the traditional gravitational field method accelerometer calibration are overcome.

The invention relates to a method and system for extracting parking spaces of underground garages in high-precision map making, comprising the following steps: S1, projecting a 3D laser point cloud including parking spaces into a 2D bird's-eye view mode image; S2, calculating an image contrast estimation index, According to the contrast estimation, different image preprocessing methods are used to obtain a binary image; S3, use the probabilistic Hough transform to detect the straight line segment of the binary image, and calculate the rotation angle of the parking line according to the detected straight line segment; S4, according to the rotation angle and the image The center point is the rotation image of the center of the circle; S5, count the number of pixels of the parking line in each row and column of the rotated image, and obtain the integral projection of the image in the horizontal and vertical directions; S6, search according to the integral projection of the image in the horizontal and vertical directions to obtain parking The coordinates of the four inner corners of the parking space are obtained; S7, the coordinates of the inner corners of the parking space are inversely transformed to the point cloud data, thereby extracting the parking space.

The present invention relates to a blue license plate segmentation and correction method, comprising the following steps: 1. For the rough positioning image of the license plate, the R channel map of the RGB channel and the V channel map of the HSV color space are used to construct a combined image, and then the highlighted blue license plate is obtained. The blue area binary image of the colored area, and then fuse it with the white area binary image highlighting the white character area of ​​the license plate to obtain a dual-area fusion binary image; 2. Perform edge detection on the dual-area fusion binary image, here On the basis of obtaining the binary image of the circumscribed contour of the license plate area, then the probabilistic Hough transform is performed on the binary image of the circumscribed contour of the license plate area to fit the contour line segment and further locate the corner points of the license plate; 3. After obtaining the corner points of the license plate, the original The license plate image is subjected to perspective transformation to obtain the rectified license plate image. This method can quickly and accurately correct the license plate under complex conditions and improve the recognition rate of the license plate.

The invention relates to a road edge detection method based on heuristic probability Hough transform. As an adaptive threshold search method, the Otsu method is robust to unstructured road region segmentation in complex environments. However, the Otsu method itself can only obtain rough segmentation results of road areas and non-road areas, but cannot obtain precise road boundaries. The method of the present invention comprises the following steps: in the double-threshold detection stage, the edge pixels connected to each other are uniformly numbered, thereby forming several subsets of the Canny edge; first, the least squares method is used for each edge point subset to carry out straight line fitting to obtain The axis of this point set. The invention is used for road edge detection.

The invention relates to a quick rectangle detection method of images with high resolution and high order of magnitude. The method comprises the following steps: firstly, pretreating each boundary pixel point set to obtain a cross point set taking a boundary pixel as a center; using a PPHT (progressive probabilistic Hough transform) algorithm and comparing with surrounding Hough parameters to obtain a straight line; and finally searching towards two sides of the straight line and deleting the whole cross point set to which the boundary pixels on the straight line belong. The process is circulated until a small quantity of pixels residues. On the basis of the extracted straight line, the established rectangle rule in which a pair of accurately matched parallel lines are detected firstly and then right-angle sides not completely matched are detected is utilized to detect the rectangles in the images. The method has good robustness for interferences caused by false boundaries and lens distortion due to dusts of a background area and is not limited by the different rectangle sizes; and thus a reliable rectangle detection method is applied for modernized industrial production of large-size rectangle boards.