擅长:python、mysql、java
<p>计算内部行的平方和,无需sqrt,直接与平方距离比较</p>
<pre class="lang-py prettyprint-override"><code>def filter_by_distance(cloud, distance=10):
# np.sum is implemented c and very fast
# axis = 1 for summing row
# no need to sqaure root (save computation)
# : stand for row, 0:3 stand for column 0, 1, 2
umask = np.sum(cloud[:, 0:3]**2, axis=1) < distance**2
# umask is boolean array, whereever it is false, that cloud point will not be shown
return cloud[umask]
</code></pre>