A (continuous) wavelet transform is given by the integral of the product between signal s and the kernel (wavelet) w, where the kernel is both shifted and stretched, allowing to extract information at different scales.
<a href="//commons.wikimedia.org/wiki/User:Berto" title="User:Berto">Jacopo Bertolotti</a>
<a rel="nofollow" class="external free" href="https://twitter.com/j_bertolotti/status/1224296204173021184">https://twitter.com/j_bertolotti/status/1224296204173021184</a>