1. What is the main purpose of image compression in digital image processing?
(A) Enhance image resolution
(B) Increase image size
(C) Reduce storage and transmission cost
(D) Improve color depth
2. Which of the following is a lossless image compression technique?
(A) JPEG
(B) RLE
(C) MPEG
(D) DCT
3. Which algorithm replaces frequently occurring patterns with shorter codes?
(A) RLE
(B) Huffman Coding
(C) DFT
(D) PCA
4. In Huffman coding, which type of symbol is assigned the shortest code?
(A) Least frequent
(B) Random
(C) Most frequent
(D) Longest pattern
5. Which compression method uses run lengths to encode sequences of data?
(A) JPEG
(B) LZW
(C) RLE
(D) Arithmetic Coding
6. LZW compression was originally used in which of the following formats?
(A) PNG
(B) JPEG
(C) GIF
(D) BMP
7. Which of the following is a lossy image compression standard?
(A) PNG
(B) JPEG
(C) TIFF
(D) RLE
8. What transform is used in the standard JPEG compression method?
(A) Fourier Transform
(B) DCT
(C) Haar Transform
(D) Wavelet Transform
9. Which compression method is considered more advanced than JPEG and uses wavelets?
(A) JPEG2000
(B) RLE
(C) Huffman
(D) MPEG
10. Which of the following is not a feature of JPEG2000?
(A) Lossless compression support
(B) Wavelet-based coding
(C) Region of interest coding
(D) Pure binary coding
11. What is the main disadvantage of lossy compression?
(A) Reduces file size
(B) Retains exact image
(C) Loss of quality
(D) Uses too much memory
12. Which of the following compression techniques is dictionary-based?
(A) Huffman
(B) LZW
(C) JPEG
(D) DCT
13. What does LZW stand for?
(A) Lossless Wavelet Zoom
(B) Lempel-Ziv-Welch
(C) Low Zoom Width
(D) Luminance Zigzag Wave
14. What is the output of Huffman coding?
(A) Tree
(B) Fixed-length codes
(C) Variable-length codes
(D) Run-length encoded image
15. What is the first step in JPEG compression?
(A) Entropy coding
(B) Quantization
(C) DCT
(D) Zigzag scanning
16. Why is DCT preferred in JPEG over other transforms?
(A) Easy to compute
(B) Localized frequency information
(C) Energy compaction
(D) High memory usage
17. Which step in JPEG compression introduces most data loss?
(A) DCT
(B) Quantization
(C) Huffman encoding
(D) Zigzag scanning
18. Which component is compressed more aggressively in JPEG compression?
(A) Luminance
(B) Chrominance
(C) Red
(D) Blue
19. What is the purpose of zigzag scanning in JPEG?
(A) Increase resolution
(B) Improve brightness
(C) Group low-frequency components
(D) Encrypt image data
20. What kind of data does RLE handle efficiently?
(A) Random patterns
(B) High-frequency textures
(C) Repeated values
(D) Noise
21. Which of the following is not a lossless compression technique?
(A) Huffman
(B) LZW
(C) RLE
(D) JPEG
22. In LZW compression, what is stored in the dictionary?
(A) Quantization matrix
(B) Pixel frequencies
(C) Character sequences
(D) DCT coefficients
23. What kind of compression is used in JPEG for entropy coding?
(A) Arithmetic coding
(B) Run-Length Coding
(C) Huffman Coding
(D) LZW
24. Which of the following is typically smaller after compression with JPEG?
(A) High-frequency components
(B) Low-frequency components
(C) DC coefficient
(D) Image header
25. What is the typical block size used in JPEG DCT?
(A) 4×4
(B) 8×8
(C) 16×16
(D) 32×32
26. What is the purpose of quantization in image compression?
(A) Increase contrast
(B) Remove high-frequency noise
(C) Reduce precision to save bits
(D) Enhance colors
27. Which transform is used in JPEG2000?
(A) Discrete Cosine Transform
(B) Fourier Transform
(C) Wavelet Transform
(D) Hadamard Transform
28. Which property of wavelet transform makes it useful for compression?
(A) Fixed frequency resolution
(B) Equal bandwidth allocation
(C) Multi-resolution analysis
(D) High computational load
29. Which of the following supports both lossy and lossless modes?
(A) JPEG
(B) JPEG2000
(C) RLE
(D) Huffman
30. What technique is used to reorder DCT coefficients in JPEG?
(A) Quantization
(B) Run-Length Encoding
(C) Zigzag scan
(D) Subsampling
31. Which algorithm builds a binary tree based on symbol frequency?
(A) RLE
(B) LZW
(C) Huffman
(D) Arithmetic
32. Which image compression format is commonly used for medical and satellite images?
(A) JPEG
(B) PNG
(C) JPEG2000
(D) BMP
33. What does entropy coding in compression exploit?
(A) Temporal redundancy
(B) Spatial redundancy
(C) Coding redundancy
(D) Color redundancy
34. What type of redundancy does RLE remove?
(A) Spatial
(B) Temporal
(C) Coding
(D) Transform
35. Which component in JPEG handles color conversion?
(A) Quantizer
(B) DCT
(C) Color space converter
(D) Huffman coder
36. Which is the most dominant frequency component in images?
(A) High-frequency
(B) Low-frequency
(C) Medium-frequency
(D) All equally
37. Why is chroma subsampling used in JPEG?
(A) Reduce spatial resolution
(B) Improve color quality
(C) Reduce data size with minimal visual loss
(D) Remove noise
38. Which compression method is most suitable for text images?
(A) JPEG
(B) LZW
(C) RLE
(D) Huffman
39. Which term describes the amount of compression achieved?
(A) Bit depth
(B) Resolution ratio
(C) Compression ratio
(D) Quantization scale
40. Which file format commonly uses LZW compression?
(A) JPEG
(B) GIF
(C) PNG
(D) BMP
41. Which of the following does not affect JPEG compression ratio?
(A) Image size
(B) Quantization level
(C) Huffman coding
(D) Display resolution
42. How does JPEG2000 achieve scalability?
(A) Fixed blocks
(B) Bit-plane coding
(C) DC component encoding
(D) Huffman compression
43. Which is a disadvantage of JPEG compression?
(A) Increased image sharpness
(B) No support for color
(C) Blocking artifacts
(D) Too slow
44. Which of the following is most robust for image quality?
(A) JPEG
(B) LZW
(C) JPEG2000
(D) Huffman
45. Which compression format offers better performance at lower bit rates?
(A) JPEG
(B) JPEG2000
(C) BMP
(D) RLE
46. Which JPEG step reduces perceptual redundancy?
(A) Huffman coding
(B) Zigzag scan
(C) Quantization
(D) DCT
47. In image compression, what is ‘lossy’ mainly defined by?
(A) Color reduction
(B) Bit-depth conversion
(C) Irreversible loss of data
(D) Slow compression
48. Which compression algorithm uses string matching and table indexing?
(A) Huffman
(B) Arithmetic
(C) LZW
(D) RLE
49. Which of the following formats is not typically compressed?
(A) BMP
(B) JPEG
(C) GIF
(D) PNG
50. Which type of compression technique results in a smaller file size but cannot reconstruct the original image exactly?
(A) Lossless compression
(B) Predictive compression
(C) Lossy compression
(D) Entropy encoding
