Output only players on a playing field

I am using opencv.js to extract players from a field with the following Mat settings:

||let high = new cv.Mat(src.rows,src.cols,hsv.type(),[70, 255, 255,255]);|
||let low = new cv.Mat(src.rows,src.cols,hsv.type(),[35,40, 40,0]);|

I input a jpg, and require the output to be just the png of the players themselves.

Does anyone know if this is achievable?

Here is the input and output example:

as you can see, i still have areas of the output image I cannot get rid of.

Does anyone know how I can potentially improve this?