A direction balance-based laser radar and camera external parameter calibration method

Abstract

This invention discloses a method for extrinsic parameter calibration of a LiDAR and camera based on directional equalization, comprising the following steps: extracting edge feature maps from the camera image and performing Euclidean distance transformation on the edge feature maps to obtain the range field and its gradient; performing voxel downsampling on the LiDAR point cloud and using a region growing algorithm to segment the principal plane from the downsampled LiDAR point cloud; solving for the intersection lines between adjacent principal planes pairwise to obtain LiDAR edge line features; transforming the LiDAR edge line feature points to the camera coordinate system and projecting them onto the image plane, and performing bilinear sampling of the range field and its gradient at the projected pixel positions; constructing a global orientation histogram and calculating the directional equalization weights; constructing a joint objective function that fuses the range field residuals and the directional equalization weights; and iteratively optimizing the joint objective function to solve for the optimal extrinsic parameters between the LiDAR and the camera. The advantage of this invention is that it improves the stability of extrinsic parameter estimation.

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