有关下列matlab语句或函数解释正确的是____。 clear all; im1=imread('Fig0617.tif'); im1=im2double(im1); [m,n,q]=size(im1); [R,G,B]=imsplit(im1); figure,subplot(1,3,1), imshow(cat(3,R*0.5,G,B)),title('R 通道减半'); set(gcf,'outerposition',get(0,'screensize')); set(gcf,'NumberTitle','off','Name','改变通道来观察图像'); subplot(1,3,2),imshow(cat(3,R,G*2,B)),title('G 通道翻倍'); subplot(1,3,3),imshow(cat(3,R,G,zeros(m,n))),title('B 通道为0');