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Scientia Silvae Sinicae ›› 2015, Vol. 51 ›› Issue (7): 129-135.doi: 10.11707/j.1001-7488.20150714

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A Target Detection Method for Artifical Harvesting Based on 2D Laser and Images

Ding Xiaokang, Yan Lei, Kong Jianlei, Liu Jinhao   

  1. School of Technology, Beijing Forestry University Beijing 100083
  • Received:2014-07-16 Revised:2014-10-28 Online:2015-07-25 Published:2015-08-14

Abstract:

[Objective] When large forestry equipment are in practice, it needs operator to make a lot of observation to determine due to the complexity of forest environments and the impact of obstacles, which result in intermittent operation, reducing operational efficiency. Especially in poor light conditions, it will greatly increase the risks for the operator. Based on 2D laser and images, harvesting targets in artificial forest were detected and identified in this study by using information fusion technology, which provided supplementary information to the operator to compensate for the lack of the human eyes. [Method] This paper presented a target detection method for artificial forest harvesting based on 2D laser and images. The main contents were: 1) Built harvesting target information collection system based on 2D laser scanner and thermal imager, where PC was applied to control the information collection. Also the collected signal pretreatment was conducted in this part. Then laser data, visible and infrared images were captured for targets. 2) Internal and external joint calibration was conducted between laser points and image to match them together, thereby obtaining the target area image we need at the same time to obtain the coordinate position of the target by the laser information, which provided the basis for subsequent target recognition. 3) Fused the visible image and infrared image. Fused image had richer information and reduced uncertainty caused by a single sensor. 4) According to the collected information, features including temperature, colors and shape were extracted to provide specific evidence for target identification. 5) On the basis of obtained features, a popular machine learning algorithms-support vector machineswas applied by training and learning with a number of samples to establish math model for features and targets. 6) The characteristic parameters of the mathematical model were optimized by 3 different optimization algorithms to improve recognition performance. [Result] Models with different optimizations were compared by ROC curves. Experiment results showed that the optimized model by GA used in this paper could recognize harvesting targets effectively and it’s correct rate could reach more than 96%. [Conclusion] Multi-sensor fusion technology was introduced into smart forestry equipment in this paper. Instead of the commonly used expensive 3D laser scanning system, 2D laser and images were combined and used. On the one hand, it saved the costs; on the other hand, for the 2D data, the data processing was faster. At the same time, the complementary among sensorsmade the measuring and identification more accurate. The results showed that the method used in this study could provide the information needed by forestry equipment operations, which improved operational efficiency and reduced operational risks.

Key words: laser, image, harvesting target, recognition, detection

CLC Number: