Draw line or a dot for a specific pixels on the image

[KevinKM]

Hi all,

I have an 8bit grayscale image, i have extracted the column indeces of Image which has defects. I need to mark the defective pixels with a line or dot indication on the image. Can anybody suggest me how to go about it.

[GerdW]

Hi Kamasani,

load your image in a picture indicator, find the defect pixels, replace them by red pixels.

Or:

Load the image, put it in the background of a XY graph. Use a XY plot to mark defect pixels.

Or:

Put the image in a intensity graph. Change the defect pixels to red…

Or:

Use IMAQ to do your job. (Can't suggest solutions here as I don't have that toolkit installed…)

[KevinKM]

Hi GerdW,

Thanks for your time,

I tried using overlay oval vi with No luck, i have attached the snippet. I am not getting any image output from the overlay oval vi. Can you please suggest where i am going wrong

[GerdW]

Hi,

as I wrote before: I don't have IMAQ installed - so I cannot comment on your code…

[falkpl · Accepted solution]

You are passing an empry array into an autoindexing for loop.  This will not execute.

The overlay looks ok if this code actually could itterate.

[KevinKM]

Hi falkpl,

Thanks for your  time, the overlay is working fine, i passed a 1D array of constant pixels (i.e 250)(Y Coordinates)

Here is my actual requirement:

I am having a Grayscale 8-bit image (3969 X 600)(To find the pixel values widthwise which has defects, X-Coordinates).

• I perform sum of column pixels to get a 1d array.
• I get the average (average= sum/size of 1d array)
• I find the pixel values above average.
• Finally i extraxt the Non-zero indeces for the pixel values. 

I am facing an issue to find the Cooresponding Y-Coordinates(Pixels for height) for the X-coordinates(Pixels for Width). So i can feed the both x & y coordinates to overlay function to mark the exact pixel with defect on the image.

I would be glad if you suggest me how to find the height pixels for the corresponding width pixels.

[falkpl]

Not sure I understand your descriprion.  Do you have a photo of the processing you are trying to do?

[KevinKM]

Hi Paul,

Thanks for your reply, I had to overlay a dot on the image for few pixels. I figured out the issue and its resolved now. Passing empty array was the problem and its all fine now.

I had posted a similar query in Machine vision forum as well, i just forgot to mark it as solution here.