Based on the decorrelation calculation of diffusion ultrasound in time-frequency domain. this paper discusses the repeatability and potential significance of Disturbance Sensitive Zone (DSZ) in time-frequency domain. The experimental study of Barely Visible Impact Damage (BVID) on Carbon Fiber Reinforced Polymer (CFRP) is carried out. The decorrelation coefficients of time. https://lockdownsecuritycanada.shop/product-category/smart-mirror-dash-camera/