Hierarchical encoding techniques allowing a good compression efficiency
and allowing to quickly recognize the outline of an image from a fraction of encoded
data. In order to realize such techniques, an image processing apparatus has a
generating unit for generating a plurality of coefficients representative of an
image, a variable length encoding unit for encoding each of the plurality of coefficients
generated by the generating unit, and a hierarchical output unit for distributing
each bit of variable length encoded data corresponding to each coefficient and
obtained through variable length encoding by the variable length encoding unit,
to a plurality of bit planes each corresponding to a level of each bit, and hierarchically
and sequentially outputting the plurality of bit planes.
