说明：该程序的作用是计算输入图像img的平均梯度值AVEGRAD
平均梯度值可以衡量图像细节反差表达的能力,是图形融合结果的一个评价算子之一
function AVEGRAD=avegrad(img)
%%%%%%%%%%%%%%%%%%%%%%%%%
%%%% this function is used to calculate
%%%% the average gradient of an image.
%%%% date :2009-4-15
%%%% 平均梯度可敏感地反映图像对微小细节反差表达的能力,可用来评价图像的模糊程度
%%%% 在图像中,某一方向的灰度级变化率大,它的梯度也就大.因此,可以用平均梯度值
%%%% 来衡量图像的清晰度,还同时反映出图像中微小细节反差和纹理变换特征.
img=double(img);
[M,N]=size(img);
gradval=zeros(M,N); %%% save the gradient value of single pixel
diffX=zeros(M,N); %%% save the differential value of X orient
diffY=zeros(M,N); %%% save the differential value of Y orient
tempX=zeros(M,N);
tempY=zeros(M,N);
tempX(1:M,1:(N-1))=img(1:M,2:N);
tempY(1:(M-1),1:N)=img(2:M,1:N);
diffX=img-tempX;
diffY=img-tempY;
diffX(1:M,N)=0; %%% the boundery set to 0
diffY(M,1:N)=0;
diffX=diffX.*diffX;
diffY=diffY.*diffY;
AVEGRAD=sum(sum(diffX+diffY));
AVEGRAD=sqrt(AVEGRAD/2);
AVEGRAD=AVEGRAD/((M-1)*(N-1));
end
我也在找呢,发现一个,共同参考下吧.
