In the laser inertial confinement fusion (ICF) experiment, the high accuracy target field coordinate system should be found to monitor the target by all kinds of physics diagnose instrument. Before the testing target is shot, the coordinate system should be transferred to the testing target, and recurrent the coordinate system before each shooting. In order to solve this problem, two set microscope optics vision instruments are designed which has autocollimating and target position monitoring functions, and its working distance is 3.8 meters，and its optic resolution is 8 micron. Firstly, the optical coordinate axis of the two instruments is adjusted orthogonally by each other, then the ICF range coordinate is transferred to a testing target by a sensor, and ensure testing target located at the center of ICF range coordinate. The instrument has already been used in Shen Guang III device, and also can be used for object monitoring and tracing in a kind of field.
This paper persents an laser and target alignment sensor (LTAS) used to automaticlly position for the ICF experimental target. LTAS which is based on optical conjugate principle can locate the targets online with its four imaging measurement systems. For the requirement of automatic positioning, presents a new method which is called offline test and online match method. With the help of target offline test device, the reference image features are provided, online images and reference images are matched in real time based on images point features, SIFT descriptors are used for extracting target feature from image which is invariant features to image scale and rotation. According to image feature, we modify the original feature vectors with 128 dimensions to a feature vectors with 32 dimensions. A fast nearest neighbor algorithm is used for feature match, and the Best-Bin-First (BBF) algorithm is used to search nearest neighbors of points, and then RANSAC algorithm is used to remove the mismatch points, A least-squares solution is used to calculate parameters between the reference image and the online image, according to the matching parameters, the target is automatic adjusted to proper attitude. By matching experiment, the position matching accuracy is within 1 μm, the angle matching accuracy is within 0.1 degree, matching time cost is less than 1 second, and meets the real-time matching requirements.