a) 5b) -5c) 8d) -8Answer: aExplanation: The mask formed by eliminating diagonal neighbors i.e. 4f(x, y), since each diagonal contain a -2f(x, y), the maskhas 5 as its central coefficient.10. Which of the following mask(s) is/are used to sharpen images by subtracting a blurred version of original image from theoriginal image itself?a) Unsharp maskb) High-boost filterc) All of the mentionedd) None of the mentionedAnswer: cExplanation: Unsharp mask sharpens images by subtracting a blurred version of original image from the original image itself.A high-boost filter is a generalized form of unsharp mask.11. Which of the following gives an expression for high boost filtered image fhb, if f represents an image, f blurred version of f, fsunsharp mask filtered image and A ≥ 1?a) fhb= (A – 1) f(x, y) + f(x, y) – f x, y)b) fhb= A f(x, y) – f(x,y)c) fhb= (A – 1) f(x, y) + fs(x, y)d) All of the mentionedAnswer: dExplanation: A high-boost filter is a generalized form of unsharp mask and is given by:fhb= A f(x, y) – f (x, y)Or, fhb= (A – 1) f(x, y) + f(x, y) – f(x, y), that can be written asfhb= (A – 1) f(x, y) + fs(x, y), where fs(x, y) = f(x, y) – f (x, y).12. If we use a Laplacian to obtain sharp image for unsharp mask filtered image fs(x, y) of f(x, y) as input image, and if the centercoefficient of the Laplacian mask is negative then, which of the following expression gives the high boost filtered image fhb, if∇2f represent Laplacian?a) fhb= A f(x, y) –∇2f(x,y)b) fhb= A f(x, y) +∇2f(x,y)c) fhb=∇2f(x,y)d) None of the mentioned
