crashing on mac (reports included)
[issue.txt](https://github.com/zddhub/opensse/files/769488/issue.txt)

Hi i have compiled and done as mentioned with instructions applied on only one model Teddy. i receive this issue as soon as i let go of the pen tool on demo. (attached error report)

When tried with non gui tool, similar errors with a jpg format, but png format of the same file worked. Same error as the gui error report . I assume this is expected, but just included to show comparison of error with gui report.

"Assertion failed: (image.type() == CV_8UC3), function compute, file ../../../opensse-master/features/galif.cpp, line 201."

![screen shot 2017-02-12 at 17 48 49](https://cloud.githubusercontent.com/assets/9059138/22864556/8c68822c-f14b-11e6-841b-a6aca8dba59f.png)
