Percentage increase and decrease from two matrices

Attaching two matrices A1 and B1. I want to calculate the percentage increase and decrease

deltaSignal = (B1 - A1);
percentageDifference = deltaSignal ./ A1;

A1 from B1. Total percentage increase and the total percentage decrease. I have done some part which I am writing here.

[Jan]

What is your question? Write down the mathematical definition of what you want to calculate. Then it is easy to convert this to Matlab.

[Joydeb Saha]

When I make the spatial map of D = B1 - A1, I found that there are some areas where I get some positive values and maximum are negative values. Therefore I want to have the total percentage change in terms of positive and negative.

[Jan]

@Joydeb Saha: Again: Please write down the mathematical definition of "the total percentage change in terms of positive and negative". While the description as text is not really clear, you do need a mathematical representation of what you want to calculate. Then the conversion to Matlab will be very easy.

[Joydeb Saha]

Ok, let me explain more clearly. See the attached image of Ice. When I make the plot for D = B1 - A1, I have this image, where you may see that there are some blue pixels, these are the positive values (Indicates the ice increase). i want to have the percentage of increase of ice (blue pixels).

[Jan]

@Joydeb Saha: How do you define "the percentage of increase of ice" mathematically? The image does not clarify this.

A mathematical definition of "percentage" means: A number of X divided by a number of Y times 100. So what are your X and Y for "total percentage increase and the total percentage decrease".

Answer 1

[Image Analyst]

You need to convert the image from RGB values to values on the color bar. See attached demo where I did that for a thermal image.