When the coost library is used with opencv3.x-4.x,

[huangzhibear]

When the coost library is used with opencv3.x-4.x, I don't know what the problem is
error: reference to ‘log’ is ambiguous
result += *a * log(ratio);
^~~

[izhengfan]

try include opencv headers before include coost headers

[izhengfan]

and don't use using namespace std / using namespace cv etc