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Implementation of the algorithm

The algorithm is implemented by the code in a conventional for loop, which begins in Listing 4 .

Listing 4 . Beginning of the for loop.
for(int cnt = 0;cnt<pixels.length;cnt++){ pixel = pixels[cnt];green = pixel.getGreen();blue = pixel.getBlue();

The loop iterates through the array of Pixel data, modifying the colors in one pixel during each iteration.

The length property of the array object

Every array object in Java contains a length property that contains the number of elements in the array. The value of this property is used in theconditional clause in the for loop in Listing 4 to establish when the end of the array has been reached in order to terminate the loop.

Get reference to the next Pixel object

The first statement inside the for loop in Listing 4 gets a reference to a Pixel object from the next array element. That reference is stored in the local variable of type Pixel named pixel that was declared in Listing 3 .

Get the red and green color values for the current pixel

Having gotten a reference to the Pixel object, the next statement calls the getGreen method on that reference to get and save the value of the green color component in the current pixel.

Similarly, the statement following that one gets and saves the value of the blue color component in the current pixel.

Both values are returned as type int , and can range in value from 0 up to and including 255.

Objective is to scale the green and blue color values

Recall that the objective is to scale the green and blue color values on a column by column basis, going from left to right across the image shown in Figure 1 in order to produce the output image shown in Figure 2 .

Organization of the pixel data

The pixel data is stored in the array on a row by row basis. In other words, the first width elements contain references to pixels in the first row of pixels going from left to right across the screen. The next width elements contain references to pixels in the second row of pixels, etc.

Compute the column number and scale factors

Listing 5 uses the modulus operator to compute the column number for each Pixel object.

Listing 5 . Compute the column number and scale factors.
//Compute the column number and use it to compute // the scale factor.int col = cnt%width;greenScale = (double)(width - col)/width; blueScale = (double)(col)/width;

An exercise for the student

Knowing the column number in which the pixel is located, the next step is to compute the green and blue scale factors necessary to satisfy the algorithm.

I will leave it as an exercise for the student to think about how the expressions contained in the last two statements in Listing 5 cause the two scale factors to vary linearly from left to right across the image in accordance with the requirements of the algorithm. (Think about the equation of a straight line from your high school math classes.)

Apply the scale factors

The Pixel class contains methods named setRed , setGreen , and setBlue that can be called to set the color values for the pixel represented by a Pixel object.

Questions & Answers

Do somebody tell me a best nano engineering book for beginners?
s. Reply
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Abhijith Reply
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s. Reply
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s. Reply
of graphene you mean?
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Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
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what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
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this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
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Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
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