PCC - Images (Lesson)
Images
Cropping Your Items
Directions, posters and other items make great billboard additions in Alice. Cropping your items closely to take off excess white space allows them to be used as objects within the scene.
My cell phones were cropped in the scene at the beginning of the module. Then they were added to Alice as Bulletin Board items and used as regular objects within the scene. They are currently standing on a table below.
The cell phones featured in the image were clipped from a site labeled free to use, share, or modify. This classification can be found on Google by clicking on the "Setting" icon, then "Advanced Search"and then turning on the appropriate usage.
Safe Searching
See the information below for video directions on safe searching. Safe searching means that you will be able to modify as you like and not have any legal repercussions.
Originally, the cell phones were hidden on the students and teacher. Then, they were put in motion to land on the table standing up. Adding objects to the Alice World is a unique way to add texture and interest, as well as to show that you are learning about Alice.
Other Bulletin Boards that you see in the scene are the posters on the wall. These were created by me and then uploaded as Bulletin Boards and positioned on the wall. Items like these are great for directions, information, titles, and many other items. Various tools on the web and on your computer will allow you to create and save items for upload elsewhere. When using Alice, think of other tools that help you add to the Alice Scene effective items for information transfer.
So use the safe search and find your own safe item to use as a billboard in your new Alice Exploratory Assignment.
Now let's add the item that you found.
Adding 2D Image to the Scene
This video adds a 2D image to the scene, demonstrates positioning, height or width changes, opacity, and a one shot procedure.
Rotating Billboard Object
The video below examines rotation of your new Billboard Object.
Image Quality
Images are made up of pixels. Pixels are the smallest unit that can be manipulated in a picture.
Lossless images allow the picture to be recreated back to its original form without the loss of accuracy in the picture.
Lossy Compression
Lossy compression of an image loses the crispness of the image when recreated as the algorithms used to recreate the picture are not as accurate.
Illustration of Lossy Compression
Illustration of lossy compression. The following picture has been turned 90 degrees the number of times indicated using lossy techniques. For example, the first picture is the accurate picture. The second picture has been turned completely 25 times using lossy technique, 90 degrees at each turn and then retaken (4 time 25 = 100). The rest have been turned using the same process more times.
As lossy compression continues, the loss continues to take its toll on the quality of the picture, until the end, the picture is unrecognizable.
Lossy compression occurs with sound and movie files as well. Movie files are mostly too large to use lossless as size limitations come into play and therefore most uses are lossy.
Compression Techniques with Text
Text compression is a technique that is extremely important with the internet to downsize documents to allow them to send quickly. There are many text compression algorithms. We will examine a few here.
Run Length: This technique replaces 2 or more characters that are together with the number of characters that are the same followed by the character.
AAAAABBBCDDDDDEEEEFFFFFFFFFFGGGH
Would become 5A3BC5D4E10F3GH a much shorter send.
Same Pattern: Replace a repeated pattern with a symbol. Here is an example.
Peter Piper Picked A Peck of Pickled Peppers.
Use a symbol to represent all of the repeated Pe pairs. The result is now
֍ter Pi֍r Picked A ֍ck of Pickled ֍p֍ers
Adding another symbol ☺for Pi we get the following
֍ter ☺֍r ☺cked A ֍ck of ☺ckled ֍p֍ers
One more symbol for ck, ♥, will compress the characters even further.
֍ter ☺֍r ☺♥ed A ֍♥ of ☺♥led ֍p֍ers
Lastly adding ♦ for er we get and ♪ for ed.
֍t♦ ☺֍r ☺♥♪ A ֍♥ of ☺♥♪ ֍p֍♦s
Think of long word documents and how this would work for complete phrases or words that were often repeated. This allows for the file size to be compressed for transmission and disk storage and reconstituted in its original form for reading electronically.
The need for compression was greatly enhanced with the internet and continues to this day. As data and documents become larger and more complex in nature the need for compression grows to be able to continue to transfer the data as quickly as possible in packets across the internet.
Are you curious about the storage of various data storage endings? Check out the list below to find out what type of compression is used.
|
File Ending |
Compression type |
|---|---|
|
.bmp |
Uncompressed image |
|
.gif |
Compressed image - lossless (256 color limitation) |
|
.jpeg |
Compressed image - Lossy |
|
.png |
Compressed image - Lossless |
|
.mp3 |
Compressed sound - Lossy |
|
.mp4 |
Compresses sound - Lossy |
|
.wav |
Uncompressed sound |
|
.zip |
Compressed files - Lossless |
Those that are uncompressed are used for specific purposes to create high quality. An uncompressed image would be for museum quality, the preservation of the actual work.
So remember, the main reason for compression is to represent the data in as few bits as possible to allow transmission as quickly as possible and to save storage space.
IMAGE CREATED BY GAVS. LOSSY COMPRESSION IMAGE SOURCED FROM WIKIMEDIA COMMONS AND USED ACCORDING TO TERMS OF USE.