Friday, December 4, 2009

An Extension For the day:.bmp/.dib

.BMP/.DIB
One of the most used extensions in the world of computers since the beginning of usage of images.
BMP stands for bitmap and as the name suggests,it is a map of bits i.e.. 1s & 0s.Here the image is stored in the form of binary data along with depth(intensity) as a multiplier.The coding of this type of file format starts with hexadecimal code in header defining the depth type of file etc..
The BMP file can be divided into parts as below
  1. Bmp file header
  2. Bitmap information header
  3. Color palette
  4. Data

The BMP file format or DIB-Device Independent Bitmap is device independent.i.e.. it determines the pixels colour without reference to display device.hence we can record images of varying quality.mostly these type of files or uncompressed or compression is based upon run length variation.i.e.dependent upon the current position of pixel.

Since the file format is simple,and no patent problems it is one of the most widely used format in applications.however the format is large in size due to no compressions.The size of a bitmap image is directly dependent on the size and quality of the image.Mostly RLE(run length encoding) compression or no compression is used.

In computer images are mainly stored in two formats viz..raster format and vector format.In raster format every point is defined whereas in vector format,from the starting point the intensit,distance etc.. are defined.It is like defining the position of bit in different co-ordinate systems(cartesian and spherical for example).Here the bitmap format follows raster format.Ever pixel is defined in terms of intensity of colours (RGB).
The name dib for the extension is used since the format is device independent!.The image quality is independent of the system on which it is being used thereby we can kno that there is no loss in t image by transfom of the same from one system to other.

The bitmap images can be edited using any of the image editors like paint,microsoft picture editor and many other bmp editors.Thus bitmap is an widely accepted uncompressed image format.