How create Local Variable

[chiliwilyx]

I need a code Matlab in code LabView. The code Matlab is this:

k = 1;
for i = 1:m
    for j = 1:n
        if(imageGray(i,j)==255)
            Vec1(k,:) = [i j];
            k = k + 1;
        end
    end
end

For this i need create a local variable "k" andI do not know. Help me please.

[TCPlomp]

In LabVIEW the wire is the variable.

It looks like you want to build a 1D array (Vec1) with all values of an array  (Gray) which are 255.

 

(note all values in the output array are 255, so the code could be a lot simpler. do an =255 on the array, count the numbers of true and build a new array.

Ton

Message Edited by TonP on 09-02-2008 06:48 PM

Message Edited by TonP on 09-02-2008 06:50 PM

Message Edited by TonP on 09-02-2008 06:50 PM

[chiliwilyx]

so so, i need to build a 2D(Vec1) array with the position in the image array of all values of this array wich are 255.

[Ipshita_C]

Hi Chilywiliyx,

Firstly, in order to look at image attributes, unless you are importing the picture as an array you will need the NI-Vision module. If you are importing the picture as a 2D array, then you can create a 2D array on the front panel. Your nested for loops can be converted to nested for loops in LabView and your if condition is a case structure. I hope that answers your question?

Ipshita C.

[altenbach]

---

chiliwilyx wrote:
so so, i need to build a 2D(Vec1) array with the position in the image array of all values of this array wich are 255.

---

OK, you need to tell us more about the desired 2D array output.

• Is it a 2xN array, where each column is a pair of coordinates pointing to the 255 values in the input?
• Is it e.g. a 2D boolean array of the same size as the input array, with all positions TRUE corrsponding the the 255 locations?
• ...?

Also remember that in LabVIEW the array indices start with zero, while in matlab they start with one.

Lets assume you have the following 2D array input:

255 126 245 053

234 255 255 110

255 080 048 255

102 002 255 255

What should the desired output array look like?

[chiliwilyx]

For this matrix... 

255 126 245 053

234 255 255 110

255 080 048 255

102 002 255 255

the desired output array is...

0 0 

1 1

1 2

2 0 

2 3

3 2

3 3

you understand me? 

 

[sgregor249]

It looks like you want to search a 2D array for a specified value and return the locations of where this value appears. Try using the attached VI. It was written in LV 8.2.

[altenbach]

Here's a quick draft. One loop ought to be enough! 😉

 

Message Edited by altenbach on 09-04-2008 01:05 PM

[chiliwilyx]

yes you are right but this example to searh only one location of a row, for exmple you have this matrix...

255 255   1

 2    255   0

 0    255 255

The out is ...

0 0

1 2

2 1

and the out desirable is...

0 0

0 1 

1 2

2 1

2 2 

[sgregor249]

Do you want the VI to find all occurances of 255 or just the first occurance of 255 on each row?

edit: You're right my VI doesnt work correctly. Just use the one that was posted after mine.

Message Edited by sgregor249 on 09-04-2008 03:16 PM