Research On Laser Target Spot Image Detection Method

The laser collimation method is widely used in the measurement of micro-displacement under actual working conditions,but the long-distance transmission of laser is easily affected by environmental noise,resulting in large error of spot center detection results,and even paralysis of the entire construction project in serious cases.Therefore,the accurate extraction of laser spot center has important economic value and practical significance,and is an important guarantee for the safe operation of the measurement system.Therefore,this paper takes laser spot as the research object,starting from image processing technology,aiming at the important problem of accurate extraction of laser spot image center,a series of studies are carried out.The specific research contents are as follows:Firstly,a spot image detection system based on laser target is designed according to the spot detection scene under actual working conditions.By summarizing the advantages and disadvantages of various spot center extraction methods at home and abroad,the basic scheme of this paper is selected,which can accurately,conveniently and quickly collect and extract the center coordinates of the spot image.Secondly,in order to overcome the staircase effect of the second-order model and the edge blurring of the fourth-order model in the traditional partial differential equation denoising model,this paper proposes a spot image denoising model based on hybrid high-order partial differential equation.The model mixes the low-order and high-order according to the relationship between the variational energy minimization and the partial differential equation.After the laser spot image is processed by the model,the spot interior can be kept smooth and the spot boundary can be kept clear.Subsequently,the model is applied to the spot video stream processing.The experimental results show that the model not only overcomes the staircase effect of the second-order model,but also has a better ability to maintain the edge compared with the fourth-order model.The denoising results of the laser spot image are superior to other improved denoising models in the subjective effect and objective evaluation indexes SNR,PSNR and MSSIM,and are more clear and accurate.Then,in order to overcome the restriction of spot image degradation caused by different intensities of external illumination,an adaptive ROI extraction algorithm based on SSIM is proposed in this paper.The structural similarity is used to adaptively match the minimum external rectangular area of the spot under strong light,which effectively reduces the influence of the noise factor of illumination on the later spot image segmentation.Finally,the laser spot image without noise is post-processed : segmentation,morphological processing and center coordinate extraction.In order to verify the accuracy of the algorithm,the overall algorithm is applied to the external environment for verification,and the spot center coordinates are extracted online analysis by simulating the noise of different light intensities.The experimental results show that the algorithm can better adapt to the influence of light and the calculation error is less than 0.05 %.It has high accuracy and can be applied to the measurement of small displacement under actual working conditions.