| Wavelet analysis is a novel research field. The wavelet transform was published up to now only for more than 10 years, it was received favors in information processing domain, and thus it obtained the widespread application and development, and has the enormous success. To study the new theory, methods and applications of wavelets is of great theoretical significance and practical value.This paper introduced the wavelet history and the basic concept of the wavelet transform as well as some applications in the image processing. This paper uses the wavelet analysis to measure the size of boat image in the freshwater-boat. Using soft-hard thresholding method, and via thresholding operation in wavelet domain, noise can be restrained, and at the same time image can be reconstructed.A wavelet-based approach for image contrast enhancement is used. On the basis of taking full advantage of multi-scale wavelet analysis, differently enhances the coefficients at each scale, achieves the image contrast enhancement with the nonlinear processed coefficient at the same scale, enhances contrast of the low-frequency sub-band image with the good whole enhancing effect. The result of the algorithm demonstrates that the algorithm avoids over-enhancement of noise while enhancing contrast of the image with good visual effect.A wavelet transform is performed on the image function to detect an image edge using B-spline wavelets. The contradiction between the detection precision of the image edges and the restraining ability of an image noise is well resolved by this method. The result proves the veracity and effectiveness of this method.After the image edge is detected, the size of the boat image is measured. Using the anomalous edge shape of boat, I make a Minimum Enclosing Rectangle (MER) of the image edge. Then the problem is translated into measuring the distance between two points. By measuring the size of boat image with this method, the result proves that this method is effective and feasible. |
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