  The block Discrete Cosine Transform (DCT) is commonly used in image and video
compression due to its good energy compaction property. The Saab transform was
recently proposed as an effective signal transform for image understanding. In
this work, we study the energy compaction property of the Saab transform in the
context of intra-coding of the High Efficiency Video Coding (HEVC) standard. We
compare the energy compaction property of the Saab transform, the DCT, and the
Karhunen-Loeve transform (KLT) by applying them to different sizes of
intra-predicted residual blocks in HEVC. The basis functions of the Saab
transform are visualized. Extensive experimental results are given to
demonstrate the energy compaction capability of the Saab transform.
