How to increase the font size of the bounding box in Tensorflow object detection module?

Find "visualization_utils.py"
This exist in "research/object_detection/utils"
And find below code, modify font size.
If it is not working, change path to absolute path.
Or copy font file to project folder.

Thank you.
#font = ImageFont.truetype('arial.ttf', 24)
font = ImageFont.truetype('/Library/Fonts/Arial.ttf', 100) #leon modify
except IOError:
font = ImageFont.load_default()

Font size up