Image file formats

Commonly, image data must be loaded into your memory from a file. Each files provides the essential mechanism for storing, archiving, and exchanging image data. Therefore, what kind of the file format is an important for your decision, What shall you do?

Raster versus Vector Data

Raster images: Images that contain pixel values arranged in a regular matrix using discrete coordinates. When enlarged, the image will break.

Vector image: Image that provides the mathematics equation using continuous coordinates, When enlarged or compressed, the image will not break.

Tagged Image File Format (TIFF)

The TIFF specification provides a range of different compression methods  and color space tags. To store a number of variations of an image in different sizes, TIFF will divide the image into three color tags, R G B and representations together in a single file. A TIFF file can contain a number of images with different properties.

Graphics Interchange Format (GIF)

GIF specification provides the image storage with a maximum depth of 8 bits, supports color shades in the range of 2 . . . 256. GIF apply two 4-bit pixels into each 8-bit byte instead of storing each pixel using one byte. Thus the format supports lossless compression and has an ability to include multiple images in a single file to create simple animations.

Portable Network Graphics (PNG)

The PNG format exceeds the capabilities of the GIF format except to create simple animations. PNG includes an alpha channel for transparency with a maximum depth of 16 bits. The format supports lossless compression.

Joint Photographic Experts Group (JPEG)

The JPEG compression method combines three components, each components compression include its limitation to 8-bit images and has specific frequency. To decompressed, using DFT to convert the lossless compress of the image.

Windows Bitmap (BMP)

The BMP format provides grayscale, indexed, true color images, and binary images. Optionally, the format supports simple lossless, run-length based compression.

Portable Bitmap Format (PBM)

The PBM consists of a series of simple file formats. Optionally, it is saved in a human-readable text format that can be easily read in a program or edited using a text editor. In addition, PBM (portable bitmap) for binary bitmaps, PGM (portable graymap) for grayscale images, and PNM (portable any map) for color images are supported.

 

Reference

Principles of digital image processing, Fundamental techniques, Wilhelm Burger Mark J. Burg