In this paper, we analyze an improved DOG filter with different parameters in horizontal and vertical directions and the improved filter uses oval recognition domain instead of round recognition domain of classic DOG filter. The improved filter is used to compare with major illumination pretreatment methods. The experiment result shows the improved method has better recognition and false detection rate.

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A global path planning method is proposed based on improved ant colony optimization according to the slow convergence speed in mobile service robot path planning. The distribution of initial pheromone is determined by the critical obstacle influence factor. The influence factor is introduced into the heuristic information to improve the convergence speed of the algorithm at an early stage. A new pheromone update rule is presented using fuzzy control to change the value of pheromone heuristic factor and expectation heuristic factor, adjusting the evaporation rate in stages. The method achieves fast convergence and guarantees global search capability. Finally, the simulation results show that the improved algorithm not only shortens the running time of global path planning, but also has a higher probability of obtaining a global optimal solution. The convergence speed of the algorithm is better than the traditional ant colony algorithm.

The demonstration of a 69.8 nm laser on 3p 3P2 - 3s 1P1 (J=2-1) transition of Ne-like Ar pumped by capillary discharge is reported in this Letter. A main current of 12 kA with rise time of 43 ns was chosen to generate the plasma in a 35 cm long capillary filling with pressure of Ar as low as 11 Pa, resulting in a gain coefficient of 0.34 cm(-1) and gain-length product of 11 at 69.8 nm. Also observed is a weak laser on 3p 3D2 - 3s 3P1 (J=2-1) transition of Ne-like Ar at 72.6 nm in the same condition. In addition, multiwavelength lasing at 46.9, 69.8, and 72.6 nm was simultaneously realized in a capillary discharge plasma column, conditioning the pressure of Ar to 13 Pa.

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