Comparison of anomalous range image suppression methods of laser radar and combination of filter methods

Laser radar could obtain the intensity image and range image synchronously, and the target is easily distinguished because of different range values, so the "Ladar" has abroad applications. However, in the range image proceeding, the target is always disturbed to illegible by speckle and random noise, how to retrain the noise as well as keep the image information becomes the crucial problem. This paper is based on the three filter methods: histogram, median, multiple level median, the methods are all based on the theory that the probability of range anomaly is far less than that of no anomaly, using the theory of stat sequence filter, could restrain the speckle and random noise very efficiency. The three methods have the different effect on the noise restraining and keeping edge from each other. To choose the methods, the contrast of each other method is made and the contrast and the characteristic have been got, the simulated result is obtained. This paper draws the conclusion that the histogram method has the best synthetically effect of the three methods, especially in the keeping edge. In the last, the filter methods are combined together to filter the raw image in different order and is found that the different order will make the effect different on the image; the reason is that the different order makes the initialization diverse for the filter methods. The result was showed in the end of the paper, while discussing the reason of the effect of the order.