[olx_designer]

Is this can be used as a feature extraction for image recognition task ? I read some time ago someone used jpeg compression as a feature extraction before DNN.

[qayxc]

This depends on the kind of features you're interested in.

If the features lead to clustering in the frequency domain, then yes. Otherwise it'd be detrimental.

Examples for features that'd work well are edges and lines. Features based on gradients wouldn't work well.

[ponderingfish]

Can be for sure by examining the coefficients. It's a little hard but can be a way to do feature detection in the frequency transform.