noise

In many areas I have found that while adding noise, we mention some specification like zero mean and variance. I need to add AWGN, colored noise, uniform noise of varying SNR in Db. The following code shows the way how I generated and added noise. I am aware of the function awgn() but it is a kind of black box thing without knowing how the noise is getting added. So, can somebody please explain the correct way to generate and add noise. Thank you SNR = [-10:5:30]; %in Db snr = 10 .^ (0.1 .* SNR); for I = 1:length(snr) noise = 1 / sqrt(2) * (randn(1, N) + 1i * randn(1, N)); u = y + noise .* snr

So I'm making a map generator that makes random islands. It uses Perlin Noise at the heart of the generator and then a method using circles with gradients to make the islands. The circle method creates a number of circles in the centerish of the map with a gradient from a colour starting at 64 down to 0. The issue is that this method is creating a un-natrual look at parts of the map with circular edges. When the perlin noise is generated for a pixel it will get that pixel on the gradient map and then mutliply it by the blue value. So if the perlin noise gives a one on pixel 1, 5 and the blue