In the world of Computer Graphics there are two major two-dimensional types: bitmap and vector images. The more common of the two is the bitmap image (also referred to a raster image). Bitmap images consist of many tiny dots of color called pixels. All of these pixels together form an image. Common bitmap images are icons on your desktop which are typically 32 by 32 pixels. On the left is an example of a paintbrush icon. It consists of 32 dots of color going in each direction. When enlarged, one can see the individual pixels. Bitmap images are resolution dependent. This means when resizing a bitmap image to be smaller, the resize command on your imaging software must throw away pixels to make the image smaller. When enlarging the image the software must create new pixels and estimate the color of the new pixels using a process called interpolation. Bitmap images are also restricted to be a rectangular shape. Some common bitmap formats are:
- BMP
- GIF
- JPEG or JPG
- PNG
- PSD (Adobe Photoshop)
The other major type of Computer imaging is Vector images. Vector images are made up of many scalable objects which are defined by mathematical equations. This is quite different than the bitmap's pixels in that these objects are lines, curves and shapes which can be modified without destroying the object itself instead of a defined dot of color. Vector images are resolution independent because they are scalable. Increasing or decreasing the size of a vector image will not affect the sharpness of the image. Another advantage of vector images is that they are not restricted to be a rectangular shape.
Vector images are usually made up of solid shapes of color or gradient instead of pixels and tend to have a cartoon-like appearance. For this reason a vector image is not a good choice for producing a photo-realistic image. On the other hand, vector graphics are continually becoming more advanced. There are tools which apply a bitmapped textures to vector objects giving them a photo-realistic appearance. Here is an article with additional information about converting between these two types of image formats as well as scanning and keeping transparency.
Common vector formats are:
- AI (Adobe Illustrator)
- CDR (CorelDRAW)
- CMX (Corel Exchange)
- DXF AutoCAD
- WMF Windows Metafile
David,
ReplyDeleteGood job on the very interesting blog post. Your overall theme is very educational and catchy. Everybody takes pictures and saves them, but not many care about whether the pictures are bitmap or vector. I think your blog effectively differentiates between the pictures and gives a constructive insight on the two types.
Good Job!
Hey David,
ReplyDeleteYou gave a very good explanation about the different between those two type of imaging. Even thought I know that both of these types are different, I didn't know how they are different. There were many time when people said that if I want to work with a high images qualities I should go with something like AI(Adobe Illustrator), now I know why. What I still don't quite get is that, our screen show these images in pixel anyway, so wouldn't vector format image are just a higher resolution version of bitmap? I might have to do more research on this.
Thanks for the great feedback, glad you liked it!
ReplyDelete