Analysis Of Speckle Distribution And Denoising Of Medical Ultrasound Speckle

With the quick maturity of ultrasonic imaging technology, there is more and more application of ultrasonic imaging. Medical ultrasound imaging equipment has many advantages, such as real-time, non-destructive, inexpensive, high sensitivity. So, clinicians commonly used in the medical profession medical ultrasound image as an important basis of the clinical diagnosis. However, in the actual imaging, with the imaging device, the imaging mechanism and other factors, resulting in the imaged image inevitably occurs speckle noise and distortion. The so-called speckle noise is a factor which effects the image quality due to the characteristics of ultrasonic imaging. Currently, most scholars believe that it is only the speckle noise and has an adverse effect on the image, so it is necessary to adopt various methods of inhibiting.In this paper, speckle noise generated in the ultrasonic imaging process has been analyzed in two ways. On the one hand, scattering phenomenon occurs.At last, in the imaging process, ultrasound speckle is formed by a series of coherent wave interfere with each other. In fact, the speckle is not the true image of the human tissue scattering particles. In addition, this ultrasound speckle has certain statistical characteristics. In accordance with the principles of ultrasound imaging, we use Field Ⅱ to simulate the speckle. First, we study theoretical knowledge of Field Ⅱ software. Then according speckle obeys the statistical characteristics of Rayleigh distribution, under the condition of the linear acoustic field simulate ultrasonic speckle model. It views transducer transmitter and receiver and the propagation and scattering of the sound field as a linear system. We add the same speckle to the X ray hand bone image closed to ultrasound image and apply noise reduction to it and the simulation linear image of the real image for human tissues with ultrasound speckle.On the other hand, the speckle as the noise of medical ultrasound diagnostic, has a negative impact, is necessary to been suppressed. ROF algorithm can effectively suppress speckle noise while preserving image detail, and thus, we use ROF full variation algorithm to remove the noise and add a local fidelity term, to get a better denoising result. In order to better describe the denoising effect, adaptive median filter algorithm and wavelet soft threshold filtering these two classical image denoising algorithm are compared with improved ROF algorithm. Due to the actual imaging also need to take into account the non-linear factors, in order to get a more convincing conclusion, it is needed to do the same operations for clinical ultrasound images. Through the gray profile curve analysis of the pixels changing in a big range of the larger area in the gray-scale image, the ROF algorithm has certain advantages in speckle denoising.To sum up. through the above-mentioned two aspects of research work, learn that field Ⅱ speckle model is more close to real speckle noise, can be used as a objective research object of research speckle denoising algorithm, for further research speckle denoising algorithm lays a foundation. At the same time, in this article the ROF algorithm in a fixed parameter range for Rayleigh distribution of speckle noise has good treatment effect.