picture array

[Lip Seng]

Hi all,

I need help on this:

The following attachments is my program.  It will open a 8-bit greyscale bmp picture file which will look for a white pixel (value of 255) on a specific location of the picture and determine which pattern it is.

The program should run like this:

When running the program, and if you open the pattern A bmp file , a message box will pop up telling you that the file is "pattern A" And if you open the pattern B bmp file , a message box pop up will tell you that it is "pattern B".  The program will know whether it is pattern A or B by determine whether there is a white pixel within a specific location.

Problem:

My program is able to determine pattern A picture file succesfully but i encountered a problem in  pattern B file, both message box pop up (this mean that the file is pattern A and pattern B). I went to check the array of pattern B picture file (using imread in matlab) whether is there any white pixel within the specific location for pattern A, but there are no white pixel there. If you open pattern B file in paint, it can be clearly seen that there are no white pixel in the specific location for pattern A.

Thank you all in advance.

Regards,

Lip Seng

[Nomis]

Hi Lip Seng,
    I think that the cause may be that you are examining a large area of the picture rather than a single pixel. The second parameter for each array dimension in the "Array Subset" function is the length of the sub-array to return, not the index of the end of the desired sub array. If you change these to 1, the vi seems to work as required (as far as I understand it anyway!). Modified vi attached
cheers,
    Simon
.

[falkpl]

If you want a single pixel from a picture array use index array (2d version will take 2 parameters)  if you are looking at a region use the array subset.  Much like in c/c++ 

if (Picture[xA, yA] == 255){isTypeA();}

Paul

[Lip Seng]

Hi Simon and Paul 

Thanks for your reply and advice. Saw my mistake for the array subset in my program.

Regards,

Lip Seng