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An image processing session
Skills: change view (zoom in or out), rotate, select a portion, crop, resize, change contrast, filter, compress
IT concepts: image processing operation
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.
Where does this topic fit?
• Internet concepts– Applications– Technology– Implications
• Internet skills– Application development– Content creation (images)
Selected image processing operations
• Rotate an image • Crop an image• Change image contrast• Apply a filter to an
image• Resize an image• Select a portion of an
image
Let’s apply these to an image, ending up with a 200 by 200 pixel head shot.
Operation: apply the “ink sketch” filter
This sort of thing took an overnight run in the era of batch processing.
Image processing programs have many such filters.
Tip for Web developers
• Capture images (or audio or video) at the highest resolution possible.
• Do all resizing, cropping, contrast modification, etc. on the high resolution image.
• The last step is compression (if any) and uploading the image to the Web.
Try this for yourself
The original picture of lucas is at:
http://bpastudio.csudh.edu/fac/lpress/netApps/image/lucasoriginal.jpg
We illustrated several image processing operations in this presentation. Without looking back, do you recall what they were?
Can you describe what each does to an image?
Can you think of any other image processing operations that we did not use in this presentation?
If one zooms in on an image is information lost or gained?
If one resizes an image, making it smaller, is information lost?
If one resizes an image, making it larger, is information gained?
If one crops an image, is information lost?
If one filters an image, is information lost?
If one compresses an image, is information lost?
If one zooms in on an image, which of its characteristics are changed?
If one resizes an image, which of its characteristics are changed?
If one crops and image, which of its characteristics are changed?
If one filters an image, which of its characteristics are changed?
If one rotates an image, which of its characteristics are changed?
If one compresses an image, which of its characteristics are changed?
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