Image Storage and Distribution

Question 1

What lossy and lossless compression are

Answer 1

Lossy compression is a method of data compression that discards some of the data in order to achieve a smaller file size, this results in a loss of quality in the final image. Lossless compression, on the other hand, is a method of data compression that does not discard any data, resulting in an exact replica of the original image.

Question 2

What the DCT is and how it can be used to compress images

Answer 2

The DCT (Discrete Cosine Transform) is a mathematical algorithm that can be used to transform an image from the spatial domain to the frequency domain. It allows to identify and eliminate redundant information in an image, making it possible to compress the image without losing quality.

Question 3

What the frequency representation of an image is (and why it is sensible to interpret an image in the frequency domain)

Answer 3

The frequency representation of an image is a way of interpreting an image as a combination of different frequency components, such as high-frequency edges and low-frequency textures. It is sensible to interpret an image in the frequency domain because it allows for better compression and manipulation of images

Question 4

How JPEG compression works

Answer 4

JPEG compression works by splitting an image into 8x8 blocks, applying the DCT to each block and then quantizing the coefficients. This process removes some of the redundant information in the image and reduces the file size