Embedded Files
Quick Activity
Have a go at creating a smiley face in the grid provided (right side) Click on the colour and then click on the grid each cell in the grid represents a pixel.
What are Bitmap Images?
A bitmap image is an image that is represented by a grid of square pixels. In a black and white image, each pixel can be either black or white. The total number of pixels in an image is known as the resolution. For example, an image that is 500 pixels wide by 500 pixels high has a resolution of 250,000 pixels ( or 0.25 megapixels). Moderns cameras take pictures over 20 megapixels in size. That’s a lot of pixels!
The gird from the quick activity is an 8 by 8 grid which means this is a 64 bitmap image 8x8 = 64
Advantages of bitmaps
Bitmaps have a small storage size, compared with the amount of data being stored ( especially when combined with lossless and lossy compression). This means that you can take a lot of images using just one SD card.
Bitmap images can be displayed very easily on computer screens, so your computer doesn’t need to use a lot of processing power just to display the image.
Most operating systems and internet browsers can display bitmap images with the need for specialist software.
Disadvantages of bitmaps
Bitmaps can only be enlarged a certain amount before the image becomes blurry or ‘pixelated’.
Lossy compression can damage images, resulting in defects on the image.
Bitmap Images to Binary
Representing a bitmap black and white image in binary is easy – starting at the top left of the image, and working you way across and then down , you write a 1 for each black pixel and a zero for each white pixel.
The binary for the image above would be:
00000000 01100110 01100110 00000000 00000000 01000010 00111100 00000000
Activity
Activity
Have a go at this pair's activity. You will need to print out the worksheet,, unless your teacher has already printed it out for you!
Click here for a worksheet to save and print out
Activity - Time to Update your learning log
Activity - Time to Update your learning log
If your teacher hasn’t already set you up this document in Google Classroom, then click on the link below to make a copy of the Binary unit learning log.
End of Lesson Game
End of Lesson Game
Can you guess the shape of each binary code questions / answers
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