In this paper, aiming at the cooperative target detection problem in the process of unmanned helicopter sliding down, a detection method based on complementary filtering is proposed, which fuses improved SSD algorithm and related filtering KCF algorithm. The improved deep learning SSD model redesigns the feature extraction structure to improve the detection effect of small and medium targets for the small target size and large scale change in the landing scene. Then use the detection results of the SSD model to correct the KCF detection, adjust the weight parameters, and output the final fusion detection results. The test results show that the improved model detection accuracy is significantly improved, the detection accuracy in various environments reaches 93.3%, which is higher than 86.1% of the classic SSD model and 87.5% of the Faster-rcnn model. The final proposed fusion detection algorithm has a success rate of 91.1% and a processing speed of 91 hz, which basically satisfies the requirements of the ship.
Stereo digital image correlation (stereo-DIC) requires the stereo-camera system to remain fixed during the measurement process. This requirement brings a lot of inconvenience to the practical application of stereo-DIC. In many application scenarios such as dynamic measurement, the external parameters of the camera are almost inevitably disturbed, which will bring great errors to the DIC measurement results. To overcome this problem, this paper proposes a three-point marking method to determine the world coordinate system and a camera pose self-estimation method based on speckle patterns. The three-point marking method can use three undeformed feature points in the field of view (FOV) to determine the world coordinate system. The proposed camera pose self-estimation method can calculate the pose parameters of the binocular camera at the shooting time of each frame of image. This method does not require plane assumptions and has good applicability. Simulations and experiments were carried out to verify the effectiveness of the proposed scheme in overcoming external parameter disturbances.INDEX TERMS Stereo digital image correlation, external parameter disturbance, self-calibration, camera pose self-estimation.
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