Figure 4From: Micro-crack detection of multicrystalline solar cells featuring an improved anisotropic diffusion filter and image segmentation techniquePre-processing by filtering in the frequency domain. (a) Original EL image. (b) Fourier spectrum after filtering with w = 6, d = 10, and σ = 12. (c) Filtered image after inverse Fourier transformation. (d-e) Results after pre-processing corresponding to images in Figure 1.Back to article page