Frame crash issue resolved

[ritikchinu]

Issue Number

ISSUE #135

Describe the changes you've made

The issue involved empty frame being captured by caffe based face detection algorithm when we approach close to the camera lens. I have added necessary conditional statement before pre-processing the facial frame to avoid the framework from crashing while executing pre-processing methods in empty frame.

####Describe if there is any unusual behaviour of your code(Write NA if there isn't)
NA

####Additional context (OPTIONAL)

####Test plan (OPTIONAL)

Checklist

• My code follows the code style of this project.
• I have performed a self-review of my own code.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have commented my code, particularly in hard-to-understand areas.
• My changes generate no new warnings.
• I have added tests that prove my fix is effective or that my feature works.
• The title of my pull request is a short description of the requested changes.