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In Y C b C r , the luminance parameter is related to an overall intensity of the image.The chrominance components are a measure of the relative intensities of the blue and red components. The inverse of the transformation in [link] can easily be shown to be the following.

R = Y + 1 . 4025 ( C r - 128 ) G = Y - 0 . 3443 ( C b - 128 ) - 0 . 7144 * ( C r - 128 ) B = Y + 1 . 7730 ( C b - 128 )

Color exercise

Download the files girl.tif and ycbcr.mat . For help on image command select the link.

You will be displaying both color and monochrome images in the following exercises.Matlab's image command can be used for both image types, but care must be taken for the command to work properly.Please see the help on the image command for details.

Download the R G B color image file girl.tif , and load it into Matlab using the imread command. Check the size of the Matlab array for this image by typing whos . Notice that this is a three dimensional array of type uint8 . It contains three gray scale image planes corresponding to the red, green, andblue components for each pixel. Since each color pixel is represented bythree bytes, this is commonly known as a 24-bit image. Display the color image using

image(A);

axis('image');

where A is the 3-D R G B array.

You can extract each of the color components using the following commands.

RGB = imread('girl.tif'); % color image is loaded into matrix RGB

R = RGB(:,:,1); % extract red component from RGB

G = RGB(:,:,2); % extract green component from RGB

B = RGB(:,:,3); % extract blue component from RGB

Use the subplot and image commands to plot the original image, along with each of the three color components.Note that while the original is a color image, each color component separately is a monochrome image.Use the syntax subplot(2,2,n) , where n = 1 , 2 , 3 , 4 , to place the four images in the same figure.Place a title on each of the images, and print the figure(use a color printer).

We will now examine the Y C b C r color space representation. Download the file ycbcr.mat , and load it intoMatlab using load ycbcr . This file contains a Matlab array for a color image in Y C b C r format. The array containsthree gray scale image planes that correspond to the luminance ( Y ) and two chrominance ( C b C r ) components. Use subplot(3,1,n) and image to display each of the components in the same figure.Place a title on each of the three monochrome images, and print the figure.

In order to properly display this color image, we need to convert it to R G B format. Write a Matlab function that will perform the transformation of [link] . It should accept a 3-D Y C b C r image array as input, and return a 3-D R G B image array.

Now, convert the ycbcr array to an R G B representation and display the color image.Remember to convert the result to type uint8 before using the image command.

An interesting property of the human visual system, with respect to the Y C b C r color space, is that we are much more sensitive to distortion in the luminance component than in the chrominancecomponents. To illustrate this, we will smooth each of these components with a Gaussian filter and view the results.

Questions & Answers

I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
Maciej
characteristics of micro business
Abigail
for teaching engĺish at school how nano technology help us
Anassong
How can I make nanorobot?
Lily
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Source:  OpenStax, Purdue digital signal processing labs (ece 438). OpenStax CNX. Sep 14, 2009 Download for free at http://cnx.org/content/col10593/1.4
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