Image masking tool to implement mask RCNN using python

I am trying to understand Mask RCNN. For that I have to input image with mask in png format while building the model.

I try to follow the article present in this blog.

The blogger used Pixel Annotation Tool.

I tried to follow her steps. I downloaded all the requirements for this tool. Like QT, Open CV, CMAKE and VS 2015 +

When I try to update the build script as mentioned here for windows. I am unable to find the make OpenCV build folder. I am in windows 10 with Python 3.7.

I also tried Lear Tool. It didn't help me.

I tried VGG annotation tool. I am able to create bounding boxes but unable to create mask in png format.

Can anyone suggest a tool for this activity.

I have posted the same in Stackoverflow. I thought of posting it here since its more relevant. I am deleting the question from stackoverflow.