Improve image quality, grainy words

Question

alessandro mutasci 2021-10-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1566146-improve-image-quality-grainy-words

评论： Rik 2021-10-18

frame11.png

Good morning, I'm using this script to obtain a sequences of image. The problem is that the quality of the written part, or more in general of the final image is poor. If I try to zoom the image, it is all grainy. Is there a way to improve it? I attach the script I use and an example of image I obtain.

path='C:\Users\Utente\Desktop\xtreno\imm\New Folder1';

Dir=dir(path);

c=figure('Visible','off');

h1=subplot(1,2,1)

annotation(c,'line',[0.733928571428571 0.7875],[0.4 0.4],'Color',[1 0 0],'LineWidth',1);

annotation(c,'textbox',[0.779571428571429 0.354761904761906 0.131142857142857 0.107142857142858],'String',{'PROBE'},'FontSize',12,...

'FitBoxToText','off',...

'EdgeColor','none');

for i=1:17

h1=subplot(1,2,1)

hold on

plot(t1(1:i),s11(1:i),'Marker','x','LineStyle','--') %s1t1 camera, s3tefibra

if i<1

plot(t2(1:i),s3(1:i),'LineWidth',2)

else

plot(t2(1:i*10-7),s3(1:i*10-7),'LineWidth',2)

end

line([t1(i) t1(i)],[-2 2],'Color',[0 0 0]);

ylabel({'Phase (-)'},'FontName','Times New Roman');

xlabel({'t (s)'},'FontAngle','italic','FontName','Times New Roman');

legend1 = legend({'Camera','Fibre'});

h2=subplot(1,2,2)

I=imread([path,'/',Dir(2+i).name]);

imshow(I);

box(h1,'on');

h1.Position=[0.13 0.135714285714286 0.5075 0.789285714285715];

set(h1,'FontSize',10,'LineWidth',1.5,'XGrid','off','YTick',[0.2 0.9],'YTickLabel',{'Liq', 'Vap'},'XLim',[t1(i)-0.2,t1(i)+0.05],'XLimMode','Manual','YLim',[-0.2,1.2],'YLimMode','Manual');

F = getframe(c);

F1(:,:,:,i) = F.cdata;

imwrite(F1(:,:,:,i), sprintf('frame%d.png', i));

end

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Rik 2021-10-18

Your image is apparently fairly small. You can either increase the size of your figure, or use a different function that allows you to set the resolution (like @yanqi liu suggested).

alessandro mutasci 2021-10-18

yes you are right, I tried the function that @yanqi liu suggested, but it's still grainy. Could you tell me how to increse the size of my figure please?

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Answer 1

yanqi liu 2021-10-18

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1566146-improve-image-quality-grainy-words#answer_810866

在 MATLAB Online 中打开

sir，please use

print(gcf,'-dpng','-r200','your_image_name')

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alessandro mutasci 2021-10-18

在 MATLAB Online 中打开

yes, using an higer DPI, it is going ok. but now I'm trying to use it for all images but it's not working. it says that there are multiple error, but I'm not understanding how to solve it.

for i=1:16

I=sprintf('frame%d.png',i)

print(I,'-dpng','-r1000','your_image_name%d')

end