Vision Detector Generator Noise Properties

I would like to add noise in terms of poor weather conditions. I only see the following properties:

HasNoise: true or false - how do I know what level of external noise has been added if it is a boolean set to true?

ProcessIntensityNoise: - what is the maximum value I can use here, without affecting the integrity of the camera, and keep it believable?

Also, setting the HasNoise to true made no difference to the longitudanal and latitude plots as specified here: model vision sensors detection example

So I am not sure what this HasNoise = true is actually doing. Please clarify, and also let me know how I can add noise due to bad weather.

Thanks.