A speckle reduction and image enhancement anisotropic diffusion method to underwater ultrasonic image based on wavelet technology

Ultrasonic inherent characteristic and underwater environment make underwater ultrasonic image have speckle noise, and image contrast is low. So need a method to reduce speckle noise and enhance image contrast at the same time. In certain applications, however, the removal of speckle and image enhancement may be two contradictory problem each other , so we difficult to gain an ideal image processing result. For this reason, considerations in characteristic of the underwater ultrasonic image, this paper provides a new speckle reduction and image enhancement anisotropic diffusion method based on wavelet technology. An anisotropic diffusion model has been established based on wavelet transform. We analyze the characteristic of the model and discuss the model's mechanism of action for removing speckle and enhance image edge of the underwater ultrasonic image. A compare experiment for real underwater ultrasonic image has been done using the method and other traditional methods. The experimental result indicates that the method proposed have strong speckle reduction and enhancement image ability. The purpose of removing speckle noise and enhancing edge at same time has been reached.