How to calculate compression ratio of image?

A imgae converted to zigzag encoding after i applied Huffman compression.Now i MAT file only.

How to calculate compression ratio

[Walter Roberson]

This question has been asked numerous times. Please search for compression ratio in the "Search Answers" box.

Answer 1

[Image Analyst]

Calculate the ratio of the size of the uncompressed file on disk to the compressed file on disk.

[S .p.aramesh S]

Thank U sir,Any sample code is there?

[Walter Roberson]

dir() and extract the Bytes field.

[elz tomz]

using matlab function imfinfo you will get image filesize. with that you can calculate cr

[Walter Roberson]

image file size does not tell you compression ratio very well. image files have headers, and in some formats can have extra comments of arbitrary size.

Most image formats default to compressing the data. JPEG defaults to compressing the data in a lossy manner (throws away information); most of the other formats preserve all of the information.

In terms of the original question, the file was said to be a MAT file, which is not an image file format, so imfinfo will not tell you anything about it.

MAT files compress by default, but not always every item.