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		<updated>2026-05-05T09:42:20Z</updated>
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		<title>Nancyvarkey at 04:54, 14 November 2018</title>
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				<updated>2018-11-14T04:54:54Z</updated>
		
		<summary type="html">&lt;p&gt;&lt;/p&gt;
&lt;a href=&quot;https://script.spoken-tutorial.org/index.php?title=Python-3.4.3/C3/Image-manipulation-using-Arrays/English&amp;amp;diff=45087&amp;amp;oldid=45018&quot;&gt;Show changes&lt;/a&gt;</summary>
		<author><name>Nancyvarkey</name></author>	</entry>

	<entry>
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		<title>Priyacst: Created page with &quot;'''Title of script''': '''Image manipulation using arrays'''  '''Author: Aditya Palaparthy, Arun KP'''  '''Keywords: Python, Ipython, imread, imshow, shape, video tutorial'''...&quot;</title>
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				<updated>2018-11-01T08:15:47Z</updated>
		
		<summary type="html">&lt;p&gt;Created page with &amp;quot;&amp;#039;&amp;#039;&amp;#039;Title of script&amp;#039;&amp;#039;&amp;#039;: &amp;#039;&amp;#039;&amp;#039;Image manipulation using arrays&amp;#039;&amp;#039;&amp;#039;  &amp;#039;&amp;#039;&amp;#039;Author: Aditya Palaparthy, Arun KP&amp;#039;&amp;#039;&amp;#039;  &amp;#039;&amp;#039;&amp;#039;Keywords: Python, Ipython, imread, imshow, shape, video tutorial&amp;#039;&amp;#039;&amp;#039;...&amp;quot;&lt;/p&gt;
&lt;p&gt;&lt;b&gt;New page&lt;/b&gt;&lt;/p&gt;&lt;div&gt;'''Title of script''': '''Image manipulation using arrays'''&lt;br /&gt;
&lt;br /&gt;
'''Author: Aditya Palaparthy, Arun KP'''&lt;br /&gt;
&lt;br /&gt;
'''Keywords: Python, Ipython, imread, imshow, shape, video tutorial'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{| style=&amp;quot;border-spacing:0;&amp;quot;&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| &amp;lt;center&amp;gt;'''Visual Cue'''&amp;lt;/center&amp;gt;&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| &amp;lt;center&amp;gt;'''Narration'''&amp;lt;/center&amp;gt;&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide title&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Welcome to the spoken tutorial on '''Image manipulation using arrays'''. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide &lt;br /&gt;
&lt;br /&gt;
Objectives &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| In this tutorial, you will learn to- &lt;br /&gt;
&lt;br /&gt;
* Read '''images''' into '''arrays'''&lt;br /&gt;
* Perform processing on them using simple array manipulations &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide &lt;br /&gt;
&lt;br /&gt;
System Specifications &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To record this tutorial, I am using &lt;br /&gt;
&lt;br /&gt;
* '''Ubuntu Linux 16.04''' operating system&lt;br /&gt;
* '''Python 3.4.3 '''and&lt;br /&gt;
* '''IPython 5.1.0'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide &lt;br /&gt;
&lt;br /&gt;
Prerequisite slide &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To practise this tutorial, you should know how to &lt;br /&gt;
&lt;br /&gt;
* run basic '''Python '''commands on the '''ipython console '''and&lt;br /&gt;
* access parts of '''arrays'''.&lt;br /&gt;
&lt;br /&gt;
If not, see the relevant '''Python '''tutorials on this website.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Slide:&lt;br /&gt;
&lt;br /&gt;
Download files&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Please download the files''' Squares.png '''and '''Python.png''' from the '''Code files''' link of this tutorial.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Save the files in the current working directory.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Squares.png &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| First we will learn how to '''access''' parts of an '''array'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For this purpose, we shall use the image '''Squares.png''' present in the current working directory.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Open terminal&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Let us start '''ipython'''.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Open the '''terminal'''.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type, '''ipython3'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type '''ipython3 '''and press '''Enter.'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
From here onwards remember to press the Enter key after typing every command on the terminal.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''import matplotlib.pyplot as plt'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''img = plt.imread('Squares.png')'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Highlight the first line&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Highlight pyplot&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To read an '''image''' into an array, we use the '''imread''' command. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Let us now read the data in '''Squares.png''' into the array '''img'''.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''import matplotlib.pyplot as plt'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Then type,&lt;br /&gt;
&lt;br /&gt;
'''img''''' is equal to''''' plt.imread '''''inside brackets inside single quotes '''''Squares.png '''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In the first line '''pyplot''' is imported from '''matplotlib '''module with '''plt '''as alias.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
This is to make use of methods like '''imread '''which are part of '''pyplot.'''&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow(img)'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| We can see the '''image''' by using the '''functions''' '''imshow''' followed by '''show'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow '''''inside brackets '''''img'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Then type,&lt;br /&gt;
&lt;br /&gt;
'''plt.show '''''open and close brackets''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
It displays the image in a separate popup window.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The original image is in the black and white.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
But here we do not see black and white, because '''imshow''' has '''mapped''' black and white to different '''colors'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
This can be changed by using a different '''color''' '''map'''. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the window&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image window to return to the IPython console.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow(img, cmap='gray')'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| In order to see the original black and white image type,&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow '''''inside brackets '''''img '''''comma''''' cmap '''''is equal to inside single quotes '''''gray'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Then type,&lt;br /&gt;
&lt;br /&gt;
'''plt.show '''''open and close brackets''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Now we can see the image in black and white.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image now.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''img'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To see what has been read into '''img''' variable, type,&lt;br /&gt;
&lt;br /&gt;
'''img'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We can see that an '''array''' is displayed'''. '''&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''img.shape '''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
'''Highlight 300x300 '''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To check the '''dimensions''' of any '''array''', we can use '''shape''' '''function'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''img.shape '''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
As we can see, we got the dimensions of the '''image'''.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The image''' Squares.png''' has the dimensions of 300 ''by ''300. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide &lt;br /&gt;
&lt;br /&gt;
Squares.png &lt;br /&gt;
&lt;br /&gt;
Point at top-left quadrant of the image &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Now, we wish to obtain the top left quarter of the image.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
To do this, we need to access top half of the '''rows''' and left half of the '''columns''' of the '''array'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We know that the '''shape''' of the '''image''' is 300 by 300.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For '''top'''-'''left''' '''corner''' of the '''image '''we need first 150 '''rows''' and the first 150 '''columns'''. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;img[:150, :150] &amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Highlight''' output'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| So type,&lt;br /&gt;
&lt;br /&gt;
'''img '''''inside square brackets colon''''' 150 '''''comma colon''''' 150'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
This gives us the '''top'''-'''left''' '''corner''' of the '''image'''.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;plt.imshow(img[:150,:150])&amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| We use the '''imshow''' '''command''' to see the '''slice''' we obtained in the form of an '''image.''' &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type as shown.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We got the required slice now.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close this image.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Pause the video. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Try this exercise and then resume the video.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide&lt;br /&gt;
&lt;br /&gt;
Exercise 1&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Obtain the square in the center of the image '''Squares.png''' with size 150 by 150. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Since we need to get center of the image, we take &lt;br /&gt;
&lt;br /&gt;
* rows from one-fourth to three-fourth of the rows i.e. from '''75''' to '''225''' and &lt;br /&gt;
* columns from one-fourth to three-fourth of the columns, i.e. from '''75''' to '''225'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Switch to terminal&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Switch to the terminal for the solution. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''plt.&amp;lt;nowiki&amp;gt;imshow(img[75:225, 75:225])&amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type as shown'''.'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Hence, we get the '''center''' of the '''image. '''&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close this image.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;img1 = img[75:225, 75:225]&amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow(img1)'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| You can also save the sliced image array to a new variable.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''img1''''' is equal to''''' img''''' inside square brackets '''''75 '''''colon '''''225 '''''comma''''' 75 '''''colon '''''225]'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Then to see the image type as shown.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image window&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close this image window&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;img[::2, ::2] &amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| We also know how to '''stride''' over an '''array.''' &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
For that we can drop '''alternate''' '''rows''' and '''columns''' out of the '''image'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''img '''''inside square brackets colon colon '''''2 '''''comma colon colon '''''2'''&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;plt.imshow(img[::2, ::2]) &amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To see this image, type as shown.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We can see that the '''scale''' has reduced. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We can observe some '''blurring''' near the '''edges '''if you scale it down further.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image window to return to the IPython console.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;plt.imshow(img[::4, ::4])&amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show() '''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To increase the '''step''' to 4, type as shown.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image window to return to the IPython console.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Python.png&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| We shall use the Python.png present in the current working directory.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Now we have an '''RGB''' image.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''img=plt.imread('Python.png')'''&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow(img)'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Let us slice the image and see what happens.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type as shown.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We can see the image. &lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image window to return to the IPython console&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''img.shape '''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Highlilght the third number&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Highlilght the first number&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| To check the '''dimensions''' of '''img''', we can use '''shape''' '''function'''. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''img.shape '''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The third number shows that there are 4 channels.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
These are corresponding to red, green, blue, and transparency value of the image.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The first number shows that the height of the image is 600. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The second number shows that the width of the image is also 600.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Type,&lt;br /&gt;
&lt;br /&gt;
'''&amp;lt;nowiki&amp;gt;plt.imshow(img[:,:,0])&amp;lt;/nowiki&amp;gt;'''&lt;br /&gt;
&lt;br /&gt;
'''plt.show()'''&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Now we will slice the red channel of the array.&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Type,&lt;br /&gt;
&lt;br /&gt;
'''plt.imshow '''''inside brackets''''' img '''''inside square brackets colon comma colon comma '''''0'''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
Then type,&lt;br /&gt;
&lt;br /&gt;
'''plt.show '''''open and close brackets.''&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
We got the required red channel of the array.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close the image&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Close this image.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide&lt;br /&gt;
&lt;br /&gt;
Summary slide &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| This brings us to the end of this tutorial. Let us summarize. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
In this tutorial, we have learned to,''' '''&lt;br /&gt;
&lt;br /&gt;
* Read '''images''' into '''arrays''' and manipulate them. &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Evaluation&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Here is a self assessment question for you to solve &lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
The shape of the variable '''img''' is (600, 600, 4). &lt;br /&gt;
&lt;br /&gt;
What will be the shape of '''img1''' if '''img1''' ''is equal to'' '''img''' ''inside brackets colon colon ''2 ''comma colon colon ''4&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Solutions &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| And the answer is, (300, 150, 4)&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Forum &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Please post your timed queries in this forum.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Fossee Forum &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Please post your general queries on Python in this forum.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Slide: TBC&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| FOSSEE team coordinates theh TBC project.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Acknowledgement &lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border-top:none;border-bottom:0.5pt solid #000001;border-left:0.5pt solid #000001;border-right:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India.&lt;br /&gt;
&lt;br /&gt;
For more details, visit this website.&lt;br /&gt;
&lt;br /&gt;
|-&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| Show Slide Thank You&lt;br /&gt;
| style=&amp;quot;background-color:#ffffff;border:0.5pt solid #000001;padding-top:0cm;padding-bottom:0cm;padding-left:0.088cm;padding-right:0.191cm;&amp;quot;| This is Priya from IIT Bombay signing off. Thanks for watching.&lt;br /&gt;
&lt;br /&gt;
|}&lt;/div&gt;</summary>
		<author><name>Priyacst</name></author>	</entry>

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