embedded in a sliding-window scheme. Such exhaustive
search involves massive computation. Efficient Subwindow
Search (ESS) [11] avoids this by means of branch
and bound. However, ESS makes an unfavourable memory
tradeoff. Memory usage scales with both image size and
overall object model size. This risks becoming prohibitive
in a multiclass system.
In this paper, we make the connection between slidingwindow
and Hough-based object detection explicit. Then,
we show that the feature-centric view of the latter also
nicely fits with the branch and bound paradigm, while it
avoids the ESS memory tradeoff. Moreover, on-line integral
image calculations are not needed. Both theoretical and
quantitative comparisons with the ESS bound are provided,
showing that none of this comes at the expense of performance.