how to change specific color of an image

horverno · June 5, 2009

hi all,

i have a nice image which i have to examine, and to do this more effective i decided to modify it a little. now i can easily recognize parts of the image with color pattern matching, but i think i can do it better. the problem is that i don't know how... so what i would like to do is to change the light blue parts of my image to white, like we can do it in paint or photoshop(paint bucket tool)... maybe it's an easy thing to do it, so i would really appreciate any kind of help

i also attached a picture to get a better understand for my problem

thanks! (and sorry for my bad english)

Neville D · June 5, 2009

Homework assignment?

N.

horverno · June 5, 2009

QUOTE (Neville D @ Jun 4 2009, 05:33 PM)

Homework assignment?
N.

it's like a school project, but my teacher doesn't know anything about labview's vison only labview in genral.... so it would be nice if someone could help

ShaunR · June 5, 2009

I'd use a different colour than turquoise!

Neville D · June 5, 2009

Like Shaun has pointed out, open the image into an RGB (colour) image buffer to store the image, then threshold the image using IMAQ Color Threshold.vi so that the range of blue (0-120) is replaced by 255 (white).

Take a look at this example for more details: Help>Find Examples (to open the Example Finder) and then search for ColorThreshold Example.vi

Neville.

horverno · June 5, 2009

QUOTE (Neville D @ Jun 4 2009, 07:10 PM)

Like Shaun has pointed out, open the image into an RGB (colour) image buffer to store the image, then threshold the image using IMAQ Color Threshold.vi so that the range of blue (0-120) is replaced by 255 (white).
Take a look at this example for more details: Help>Find Examples (to open the Example Finder) and then search for ColorThreshold Example.vi

Neville.

thanks, but i forget to mention that threshold is not an option for me:

1. i need all of the parts except the turquoise

2. i need the colors to identify if the legends are ok

but threshold gave me an idea, if i could perfectly threshold it (so turquoise and white to white all other to black) i could add/nor/xor (whichever will work) the thresholded and the original images so just keep those parts of the original image which is black on the thresholded one... that may give me the desired result

i will try this out as soon as possible but i donno if it's the quickest way to do it. i also attached a picture about how i imagined to do this

so i'm still curious if labview has something like photoshop's paint bucket tool because that would be just the perfect solution for me

horverno · June 6, 2009

QUOTE (horverno @ Jun 4 2009, 10:01 PM)

thanks, but i forget to mention that threshold is not an option for me:

1. i need all of the parts except the turquoise

2. i need the colors to identify if the legends are ok

but threshold gave me an idea, if i could perfectly threshold it (so turquoise and white to

white

all other to

black

) i could add/nor/xor (whichever will work) the thresholded and the original images so just keep those parts of the original image which is black on the thresholded one... that may give me the desired result

i will try this out as soon as possible but i donno if it's the quickest way to do it. i also attached a picture about how i imagined to do this

so i'm

still curious

if labview has something like photoshop's paint bucket tool because that would be just the perfect solution for me

now i've solved the problem, and it's working (more or less) like i expected! there are some unwanted dark objects at the top of the buttons, but i will remove them with a cleverer masking before i remove turquoise color

so this method what i mentioned before is like a universal way to remove one specific color, but don't forget to convert the thresholded image back to rgb with IMAQ Cast Image - that was the hardest thing for me to figure out

i will share my solution with all of you it may helps others later...