Image Compression and JPEG

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What is the primary goal of the compression process in image and video files?

To convert all images to BMP format

To increase the file size for better quality

To separate chromatic and achromatic channels

To make the file smaller and reduce storage requirements (correct)

Why is the YCbCr color space used in JPEG compression?

Because it is more compatible with computer monitors

Because it is a more widely used color space than RGB

Because it is a patented color space

Because it separates achromatic and chromatic channels, allowing for subsampling (correct)

What is the result of subsampling the chromatic components in JPEG compression?

Reducing the amount of bit allocated to the image (correct)

Reversing the order of the color channels

Converting the image to grayscale

Increasing the amount of bit allocated to the image

Why are humans more sensitive to differences in brightness than to differences in color?

Because the human visual system is more sensitive to brightness (B) Signup and view all the answers

What is the benefit of reducing the file size of an image or video file?

It allows for faster transmission over limited bandwidth (D) Signup and view all the answers

What is the tradeoff for reducing the file size of an image or video file?

Reducing the storage requirements and potentially affecting image quality (C) Signup and view all the answers

What is the primary purpose of the zigzag scan in JPEG compression?

To separate high-frequency coefficients from low-frequency coefficients (C) Signup and view all the answers

If we want a higher compression ratio and lower image quality, what should we do?

Decrease the quality level to < 50 (A) Signup and view all the answers

What is the purpose of DPCM encoding in JPEG compression?

To reduce the number of bits required to represent the DC coefficient (B) Signup and view all the answers

What is the effect of normalization on the DCT coefficients?

It subtracts 128 from the coefficients (D) Signup and view all the answers

What is the relationship between the quality level and the compression ratio in JPEG compression?

As the quality level increases, the compression ratio decreases (A) Signup and view all the answers

What is the purpose of quantization in JPEG compression?

To discard some of the DCT coefficients (D) Signup and view all the answers

What is the primary purpose of adding 128 to the image values in the JPEG compression process?

To shift the image values to a more visually acceptable range (B) Signup and view all the answers

What is the compression ratio if the size of the original image is 32768 bytes and the size of the compressed image is 15632 bytes?

2.09 (C) Signup and view all the answers

What is the effect of increasing the compression ratio on the image quality?

It decreases the image quality and increases artifacts (C) Signup and view all the answers

What is the purpose of applying the Fourier transform to an image in the JPEG compression process?

To convert the image from spatial domain to frequency domain (A) Signup and view all the answers

What is the relationship between artifacts and compression ratio in the JPEG compression process?

Artifacts are directly proportional to the compression ratio (B) Signup and view all the answers

In the JPEG compression process, what is the purpose of quantizing the image values?

To reduce the size of the compressed image (D) Signup and view all the answers