HSMF: hardware-efficient single-stage feedback mean filter for high-density salt-and-pepper noise removal

Noise is an unwanted element that has a negative impact on digital image quality. Salt-and-pepper noise is a type of noise that can appear at any point during the acquisition or transmission of images. It is essential to utilize proper restoration procedures to lessen the noise. This paper proposes a hardware-efficient VLSI architecture for the feedback decision-based trimmed mean filter that eliminates high-density salt-and-pepper noise in the images. The noisy pixels are identified and corrected by considering the neighbouring pixels in a 3 \(\times\) 3 window corresponding to this noisy centre pixel. Either the mean of the horizontal and vertical noisy pixels or the mean of noise-free pixels in the window is computed. This mean value is fed back and the noisy centre pixel is updated immediately, such that this updated pixel value is used henceforth for correcting the remaining corrupted pixels. It is observed that this procedure helps in removing the noisy pixels effectively even if the noise density is high. Additionally, the designed VLSI architecture is efficient, since the algorithm does not require a sorting process and the computing resources required are less when compared to other state-of-the-art algorithms.