312-49 · Question #90
312-49 Question #90: Real Exam Question with Answer & Explanation
The correct answer is B: 8x8 pixels. The JPEG compression algorithm works by dividing an image into non-overlapping blocks of 8x8 pixels. Each 8x8 block is then processed independently using the Discrete Cosine Transform (DCT), which converts the spatial pixel data into frequency domain components. High-frequency co
Question
JPEG is a commonly used method of compressing photographic Images. It uses a compression algorithm to minimize the size of the natural image, without affecting the quality of the image. The JPEG lossy algorithm divides the image in separate blocks of____________.
Options
- A4x4 pixels
- B8x8 pixels
- C16x16 pixels
- D32x32 pixels
Explanation
The JPEG compression algorithm works by dividing an image into non-overlapping blocks of 8x8 pixels. Each 8x8 block is then processed independently using the Discrete Cosine Transform (DCT), which converts the spatial pixel data into frequency domain components. High-frequency components (fine detail) are then quantized (reduced in precision) more aggressively than low-frequency components (broad color areas), which is the source of the 'lossy' compression. This 8x8 block size is a fundamental characteristic of the JPEG standard (ISO/IEC 10918-1) and is why JPEG artifacts often appear as visible 8x8 tile-like blocks at high compression levels.
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