A 4 × 4 digital image has pixel intensities (𝑈) as shown in the figure. The number of pixels with 𝑈 ≤ 4 is:

A.

3

B.

8

C.

11

D.

9

Solution:

We are given a 4 × 4 digital image with pixel intensities, and asked to count how many pixels have intensity U ≤ 4.

Let’s read the matrix from the image:

0 1 0 2  
4 7 3 3  
5 5 4 4  
6 7 3 2  

Now, count the number of values ≤ 4:

Row 1: 0, 1, 0, 2 → ✅ all 4
Row 2: 4, 7, 3, 3 → ✅ 4, 3, 3 → 3
Row 3: 5, 5, 4, 4 → ✅ 4, 4 → 2
Row 4: 6, 7, 3, 2 → ✅ 3, 2 → 2

Total: 4 (row 1) + 3 (row 2) + 2 (row 3) + 2 (row 4) = 11


✅ Correct answer: (C) 11