Compare tool works with just images and labels

[bkowshik]

While cleaning up datasets, we want to look at just the images and their labels. The current rs compare requires at-least one masks directory and this PR makes the masks directory optional, one ore more to be precise! Now, we could use this tool to generate images like below:

[bkowshik]

:thumbsup:

Things I have tested rs compare for are:

• Slippy map dirs for images and masks (this branch)
• Slippy map dirs with images, masks and predicted masks

Something that I have not done with this tool is the following but, I don't see any blockers for something like this not to work.

• Slippy map dirs with images, masks, probs, and predicted masks

One additional functionality that rs compare tool handles is filtering by min/max percentages of masks not background. The use-case here is to filter out images that have predictions above or below a threshold. Breaking that functionality out of this tool would allow us to create a generic rs compare that given two or more slippy map directories of images, combines them into one image.

Did I understand you correctly?

[daniel-j-h]

What I meant was

• removing the threshold check since it's orthogonal to this tool's core responsibility
• taking a list of paths to slippy map directories from the command line
• walking all slippy maps in parallel, creating one image with all slippy map tiles next to each other