The Research Of Hydrogel Deformation Characteristics Based On Nonsample Contourlet Transform And Fuzzy C-means Clustering Algorithm

As a kind of hydrogel, Intelligent hydrogel contains the feature of stimulus responsive when the external environment changes. In the paper, we research the volume change characteristics of intelligent hydrogel as the temperature changes. Aiming at the difficult problem that how to measure the state of the hydrogel’s deformation without touching, a method of measurement based on image analysis is proposed, which can monitor hydrogel deformation characteristics through the entire process to get accurate calculation of the hydrogel volume change. In this method, the series of images are first gathered through a CCD digital camera during the process of hydrogel temperature experimental. And then, precise location to hydrogel and the staff guage are carried on separately in each image. Finally we calculate the data of hydrogel deformation through effective steps.Image enhancement, image tilt correction, image segmentation, calculation of hydrogel deformation have been analyzed and researched separately, the prime task is as follows:(1) Image enhancement:Aiming at the problem that the experiment images’quality drops caused by insufficient illumination、low contrast、edge blur、big noise, a method of image enhancement algorithm based on non sampling contourlet transform has been used. The experiment indicated that this algorithm has a good enhancement, it enhanced details of the image and inhibit uneven illumination while retaining the image’s original appearance. It surpasses traditional algorithm such as histogram equalization and wavelet transform algorithm in the subjective visual effect and objective evaluation.(2) Staff guage position:Based on the characteristics of rich edge line in staff guage region. We make use of edge detection combining line filter algorithm to locat staff guage. Firstly the enhanced images are carried on vertical edge detection by Prewitt operator, then the most background interference lines are removed by linear filtering algorithm. Finally, the staff guage is located by prior information and line scan.(3) Image tilt correction:Aiming at the problem that the tilt can’t get the calculation of volume accurately, a horizontal tilt correction algorithm based on vertical projection and rotation of axis is used in the paper. The algorithm gets through vertical projection analysis of two value image in different angle of rotation of axis to determine tilt angle. Experimental results show that this method is simple in principle and has small computation. The result of correction is well.(4) Image segmentation:A method to hydrogel image segmentation based on FCM algorithm is proposed based on the situation that there is obvious color and shape difference between object region and background region in the experimental images, and its histogram has two obvious peaks. Experiment results show that the proposed method can overcome the adverse effects caused by noise, and it also has advantages of high precision, low computation and strong good real-time operation.