Abstract: Equipment running for long period in high temperature and high pressure environments often experience equipment failure due to cracks, making accurate defect identification crucial for improving equipment operation safety. Waveguide array technology can address the issue of sensor failure at high temperatures, enabling visual imaging of defects in such environments using waveguide array sensor devices. However, due to factors such as excitation pulse influence, acoustic attenuation, diffraction and other acoustic effects, waveguide array imaging faces challenges with insufficient vertical resolution. To tackle this problem, we propose the sparse blind deconvolution algorithm to enhance the image quality of waveguide arrays. Finite element simulation is used to verify the effectiveness of the algorithm in detecting cracks with different angles while experiments are conducted to test and validate its performance. We find that the imaging effect of waveguide arrays is significantly influenced by the angle between the crack and ultrasonic propagation direction. When the crack direction aligns closely with ultrasonic propagation direction, it becomes difficult to identify crack characteristics accurately. Employing the sparse blind deconvolution algorithm can improve imaging clarity, weaken the impact from diffraction effects at crack tips, enhance vertical resolution and improve the detection accuracy.