Changing Variable from logical to double

Fx=edge(I1,'Sobel','vertical',0.001); 

While executing above line the follwoing error message is received

"Variable Fx must be of data type double. It is currently of type logical. Check where the variable is assigned a value."

How change Fx type feom logical to double

[Adam Danz]

I don't think that line caused the error. That line just assigns the output to Fx. If the answer I provided doesn't solve the problem please provide the full copy-pasted error message.

[Sivakumar Rajagopal]

Variable img_heq must be of data type uint8. It is currently of type double. Check where the variable is assigned a value.

[Adam Danz]

This error message doesn't match the error message in your question. It references a different variable name and describes a different error.

It also doesn't appear to be a complete error message showing the line number and other impotant bits of information.

[Sivakumar Rajagopal]

I have modified it as

Gx=[-1,0,1;-2,0,2;-1,0,1];
Fx=conv2(I,Gx); 

Now it is showing the following error

Variable Fx must be of size [500 500]. It is currently of size [502 502]. Check where the variable is assigned a value.

[Adam Danz]

1) What is I?

2) Are you using Matlab's conv2() or are you using a different function with the same name? To verify, run,

which conv2

3) Again, I don't think you're sharing the full error message (all of it).

[Sivakumar Rajagopal]

1) A=img;T=rgb2gray(A); I = double(T);

2) Yes Matlab's conv2()

3) It is a error message generated under coursera Matlab valiation

[Adam Danz]

Again, it makes no sense to me why this line

Fx=conv2(I,Gx); 

would generate this specific error

Variable Fx must be of size [500 500]. It is currently of size [502 502] . . . . .

That line is merely assigning the output to variable Fx. I think the error is being generated somewhere else in a line where you're using the variable Fx. Could you provide a screenshot of the error and the code that causes the error? I'm unfamiliar with Coursera Matlab - does that mean you are running matlab online through a coursera portal or are you running Matlab on your computer using a license provided by Coursera?

If the output has an unexpected size, read about the conv2 output size here.

To show that the code should not cause an error (given a proper image file), this runs fine:

RGB = imread('peppers.png'); % Built-in matlab file
I = rgb2gray(RGB);
Gx=[-1,0,1;-2,0,2;-1,0,1];
Fx=conv2(double(I),Gx);

[Sivakumar Rajagopal]

Ok Let me try

Answer 1

[Adam Danz]

"How change Fx type from logical to double"

FxDlb = double(Fx); 

alternatively,

FxDlb = Fx * 1; 
% or
FxDlb = Fx + 0; 

[Sivakumar Rajagopal]

ok Thanks

[Adam Danz]

Glad I could help.