A 4 x 4 digital image has pixel intensities (U) as shown in the figure. The number of pixels with U <= 4 is: Pixel intensity matrix: 0 1 1 0 2 4 7 3 3 5 4 5 6 7 3 2 A. 3 B. 8 C. 11 D. 9

GATE 2025 · General Aptitude · Digital Image Processing · easy

Answer: 11 pixels satisfy U <= 4. Answer: C.

  1. Count qualifying pixels in Row 1: 0, 1, 1, 0 are all <= 4. Count = 4.
  2. Count qualifying pixels in Row 2: 2 <= 4 (yes), 4 <= 4 (yes), 7 <= 4 (no), 3 <= 4 (yes). Count = 3.
  3. Count qualifying pixels in Row 3: 3 <= 4 (yes), 5 <= 4 (no), 4 <= 4 (yes), 5 <= 4 (no). Count = 2.
  4. Count qualifying pixels in Row 4: 6 <= 4 (no), 7 <= 4 (no), 3 <= 4 (yes), 2 <= 4 (yes). Count = 2.
  5. Sum all qualifying pixels: Total = 4 + 3 + 2 + 2 = 11.