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Asked by satish thapaliya on 19 Nov 2012

a=0.85; for i=1:7 filename=strcat('D:\2nd year\EXP season 2\Dry\cat1\',num2str(i),'.bmp'); I=imread(filename); I1=I(:,:,2); I2=I(:,:,3); G_Channel_cat1(i-2)=mean(mean(I1(293+(-5:5),285+(-5:5))))-mean(mean(I2(293+(-5:5),285+(-5:5))))*a; end

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Answer by Walter Roberson on 19 Nov 2012

Accepted answer

When i is 1, i-2 is going to be -1, and you cannot store into element number -1 of G_Channel_cat1.

It is not obvious what you are trying to do in that assignment statement, so I cannot suggest any fix other than not subtracting 2 from "i" at that point.

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satish thapaliya on 20 Nov 2012

Here is the code and error message

a=0.85; for i=3:9 filename=strcat('D:\2nd year\EXP season 2\Dry\cat1\',num2str(i),'.bmp'); I=imread(filename); I1=I(:,:,2); I2=I(:,:,3); G_Channel_cat1(i-2)=mean(mean(I1(293+(-5:5),285+(-5:5))))-mean(mean(I2(293+(-5:5),285+(-5:5))))*a; end for i=3:9 filename=strcat('D:\2nd year\EXP season 2\Dry\cat2\',num2str(i),'.bmp'); I=imread(filename); I1=I(:,:,2); I2=I(:,:,3); G_channel_cat2(i-2)=mean(mean(I1(301+(-5:5),284+(-5:5))))-mean(mean(I2(301+(-5:5),284+(-5:5))))*a; end for i=3:9 filename=strcat('D:\2nd year\EXP season 2\Dry\cat3\',num2str(i),'.bmp'); I=imread(filename); I1=I(:,:,2); I2=I(:,:,3); G_channel_cat3(i-2)=mean(mean(I1(310+(-5:5),283+(-5:5))))-mean(mean(I2(310+(-5:5),283+(-5:5))))*a; end for i=3:9 filename=strcat('D:\2nd year\EXP season 2\Dry\cat4\',num2str(i),'.bmp'); I=imread(filename); I1=I(:,:,2); I2=I(:,:,3); G_channel_cat4(i-2)=mean(mean(I1(320+(-5:5),285+(-5:5))))-mean(mean(I2(320+(-5:5),285+(-5:5))))*a; end x=[0.121,0.422,0.844,4.219,12.053,21.094,60.267]; for i=1:7 y(i)=(G_channel_cat1(i)+G_channel_cat2(i)+G_channel_cat3(i)+G_channel_cat4(i))/4; end plot(y,x,'r')

??? Undefined function or method 'G_channel_cat1' for input arguments of type 'double'.

Walter Roberson on 20 Nov 2012

Your first "for" loop assigns to G_Channel_cat1 which has an upper-case C. All your other variables use a lower-case C there.

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