1. imwrite 函數可以實現灰度圖片的保存；
2.saveas 保存彩色圖片
figure
imagesc(DefocusedImage{1,55})
set(gca,'XTick',[]) % Remove the ticks in the x axis!
set(gca,'YTick',[]) % Remove the ticks in the y axis
set(gca,'Position',[0 0 1 1]) % Make the axes occupy the hole figure
saveas(gcf,'Figure55','png')