frame_id of the published filtered image

[sayali-purdue]

A filtered image is published at line 85 in soft_color_filter.cpp. During static code review, I found that frame_id field of this published image is not set. I would really appreciate if you could provide me a couple of details:

1. what is the reference frame for the filtered image? Is it same as that of the raw image input?
2. As a developer of this code, do you think this frame_id info can be useful to others, who would want to use the soft_color_filter node?

Thank you!