Why doesn't JPEG use 1D DCT for image compression?

1. Why 2d DCT is used in JPEG image compression?
2. Why JPEG compression is not always suitable for compression of images?
3. What compression algorithm is used for JPEG?
4. Why is DCT preferred over DFT in image compression?

Why 2d DCT is used in JPEG image compression?

The DCT can be used to convert the signal (spatial information) into numeric data ("frequency" or "spectral" information) so that the image's information exists in a quantitative form that can be manipulated for compression.

Why JPEG compression is not always suitable for compression of images?

While JPEG compression can help you greatly reduce the size of an image file, it can also compromise the quality of an image - and if you aren't careful, there may not be any recovery. It is for this reason that we recommend saving your images in a lossless format such as TIFF.

What compression algorithm is used for JPEG?

JPEG uses a lossy form of compression based on the discrete cosine transform (DCT).

Why is DCT preferred over DFT in image compression?

> DCT is preferred over DFT in image compression algorithms like JPEG > because DCT is a real transform which results in a single real number per > data point. In contrast, a DFT results in a complex number (real and > imaginary parts) which requires double the memory for storage.