Well, My Science project is due in two days, I've got everything basically done. I had to compress JPEG images. But I need some sort of %26quot;Data%26quot; to show that there was a difference in the image, Though it is very obvious. I know the file size changed but how would I be able to say something about the quality, in something that has numbers? .-.
Does the pixel count change after compression?
JPG compression is of a science of it's own and is somewhat a guarded secret.
The name %26quot;JPEG%26quot; stands for Joint Photographic Experts Group, the name of the committee that created the standard. The group was organized in 1986, issuing a standard in 1992, which was approved in 1994 as ISO 10918-1. JPEG is distinct from MPEG (Moving Picture Experts Group), which produces compression schemes for video.
The JPEG standard specifies both the codec, which defines how an image is compressed into a stream of bytes and decompressed back into an image, and the file format used to contain that stream.
If the amount of compression is too much your image will look very blocky and jagged. The physical size, say 3000x2000 pixels does not change, but the contents INSIDE these dimensions, do, and sometimes with very bad results.
JPG's are like freeze dried foods. The water has been taken out and the food is smaller, lighter and looks like heck until you put water back in, however, once a image is a JPG, it is forever %26quot;ruined%26quot; even if a little, and you can not %26quot;re-add water%26quot; to make it whole again.
Instead of showing numbers, show a series of pictures with different levels of compression along with Googled text on how JPG's work, or don't, and show the bad image results with too much compression..
What Data you could show could be screen grabs of the file size as each level of compression is applied and the image now takes up less and less space, but now looks worse and worse..
Good luck..
Bob - Tucson
Does the pixel count change after compression?
the %26quot;resolution%26quot; means pixels per mm or something like that, the higher resolution the clearer the picture and greater number of pixels. if you're using a program like adobe photoshop it will tell you the resolution under image size. normal pictures from the internet are usually 72 pixels, if you increase it to 150, the picture shrinks but is clearer. the human eye cannot distiguish anything clearer than approx 150 pixels so its not worth going higher than that, though it is possible.
