Do you want to plot all in the same axes?
clc;clf;hold all
mean_v=[];
std_d=[];
inter=[];
A=[ 30,31,12, 9
17,12,25,10
12, 8,17, 9
31,12,26,22];
A=double(A);
x=size(A,1);y=size(A,2);
for interval=0:10:20
max_A=max(max(A));min_A=min(min(A));
for i=1:x
for j=1:y
val=A(i,j);
tone_ival=[(val-min_A)*(interval/(max_A-min_A))];
B(i,j)=tone_ival;
end;
end;
disp(round(B));
for i=1:1:2
for j=1:1:2
ROI(i,j)=B(((x/2)+(i-1)),((y/2)+(j-1)));
end;
end;
disp(round(ROI));
%%%calculate mean value
sum=0;
for i=1:1:2
for j=1:1:2
sum = sum + ROI(i,j);
end;
end;
mean_value = sum / 4;
disp(mean_value);
%%%calculate std deviation
sum_dev = 0;
for i=1:1:2
for j=1:1:2
sum_dev = sum_dev + ((ROI(i,j)- mean_value)^2);
end;
end;
std_dev = ((sum_dev/(4-1))^(1/2));
disp(std_dev);
inter=[inter interval];
mean_v=[mean_v mean_value];
std_d=[std_d std_dev];
end
plot(inter,mean_v)
plot(inter,std_d,'r')
xlabel('intervals')
legend('mean values','std dev values',2)
