GATE 2025 DA – Question 3
A 4 × 4 digital image has pixel intensities ($U$) as shown in the figure. The number of pixels with $U \le 4$ is:
| 0 | 1 | 0 | 2 |
|---|---|---|---|
| 4 | 7 | 3 | 3 |
| 5 | 5 | 4 | 4 |
| 6 | 7 | 3 | 2 |
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Show answer and explanation
Correct answer: (C) 11
Explanation
Count the pixels row by row. The first row (0, 1, 0, 2) has 4 pixels with $U \le 4$. The second row (4, 7, 3, 3) has 3, because 7 is too large. The third row (5, 5, 4, 4) has 2. The fourth row (6, 7, 3, 2) has 2. The total is $4 + 3 + 2 + 2 = 11$.