Image Compression

I want some information about this built_in function:

[cr,bpp] = wcompress('c',X,X2.wtc','ezw','maxloop',12);

- what about 'maxloop' and 12 also waht about if increase or decrease this number "12" ?

- this method is lossy compresion . what are methods that lossless compression?

thank you

Answer 1

[Image Analyst]

PNG is a lossless compression. It is very commonly used and increasingly so. Just create a PNG file with imwrite(). JPEG2000 also has a lossless compression option.

[Walter Roberson]

JPEG (pre-2000) also has a lossless compression option.

Answer 2

[Wayne King]

The 'maxloop' variable sets the maximum number of steps, if you decrease it too much, then your compression won't be optimal, if you increase it too much, you're just wasting computation effort, because the compression won't improve. You can experiment a bit.

wcompress() implements various lossy compression algorithms, see truecompdemo.m and datacompression.m for examples.

[Wayne King]

ImageAnalyst has given you lossless compression options.