In case of and , where , and and are integer constants , the wavelet transform is called discrete wavelet transform ( of continuous signal ) .
Using a wavelet transform , the wavelet compression methods are adequate for representing transients , such as percussion sounds in audio , or high-frequency components in two-dimensional images , for example an image of stars on a night sky . This means that the transient elements of a data signal can be represented by a smaller amount of information than would be the case if some other transform , such as the more widespread discrete cosine transform , had been used .