Dr Md Kabirul IslamProfessor and HeadDepartment of MICA

Daffodil International University

Wednesday, April 12, 2023 1

Contents of Today Lecture Details of Image

- Digital Image- Digital Image format- Bitmaps- Making still images-Capture and editing- Vector drawing- Natural lights and color- Image file format- Some software for creating images

Wednesday, April 12, 2023 2

Digital ImageTwo dimensional matrixRepresenting intensity value called pixel For two intensity values for black and

white, they are represented by the numbers 0 and 1; such images are called binary-valued images.

If 8-bit integers are used to store each pixel value, the Gray-levels range from 0 (black) to 255 (white).

Wednesday, April 12, 2023 3

Digital Image FormatCaptured Image Format

This format is specified by two main parameters: spatial resolution, which is specified as pixels x pixels (eg. 640x480)and color encoding, which is specified by bits per pixel. Both parameter values depend on hardware and software .

Stored Image FormatWhen we store an image, we are storing a two-dimensional array of values, in which each value represents the data associated with a pixel in the image. For a bitmap, this value is a binary digit.Wednesday, April 12, 2023 4

Pixel and ResolutionFirst lets take care of some terminology.Pixel, short for a picture element is the

smallest unit of an digital imageThe resolution of images are expressed in

terms of number of pixels, however, images being two dimensional, it is customary to express the resolution as X by Y, for example 640X480 which is 640 columns by 480 rows, or height x width, or columns x lines.

Another way of expression resolution is to use the aspect ratio which is the ratio of the lines to the columns.

Wednesday, April 12, 2023 5

Making Still ImagesBitmaps ( or paint graphics) – used for photo-realistic images and detailed drawings

Vector graphics – used for lines, polygons and other mathematical objects

Saved as GIF,JPEG,PNG files with compression

Making Still Images- Still images may be small or large, or even full screen.

- Whatever their form, still images are generated by the computer in two ways:

- as bitmap (or paint graphics) and as vector-drawn (or just plain drawn) graphics.

Wednesday, April 12, 2023 7

Making Still ImagesCapturing and Editing Images

It is possible to use the Prt Scr key available in the keyboard to capture a image.

Vector DrawingMost multimedia authoring systems provide for use of vector-drawn objects such as lines, rectangles, ovals, polygons, and text. Programs for 3-D animation also use vector-drawn graphics. For example, the various changes of position, rotation, and shading of light required to spin the extruded.

Wednesday, April 12, 2023 8

Making Still ImagesStills are drawn in one of two ways and are usually compressed Bitmaps

Vector-drawn graphics

Bitmaps

Bitmap is derived from the words ‘bit’, which means the simplest element in which only two digits are used, and ‘map’, which is a two-dimensional matrix of these bits.

A bitmap is a data matrix describing the individual dots of an image.

BITMAPS

A simple information matrix describing the dots or pixels which make up the image

Make it with paint or drawing program

Grab it and (save it) then paste it into you application

Scan or digitize an image

BitmapsBitmaps are an image format suited

for creation of:Photo-realistic images.Complex drawings.Images that require fine detail.

BitmapsBitmapped images are known as

paint graphics.A bitmap is made up of individual

dots or picture elements known as pixels or pels.

Bitmapped images can have varying bit and color depths.

Bitmaps- Simple information matrix- Describing the individual dots- Smallest elements of resolution Example: one-dimensional matrix is required for monochrome

(black and white)

Wednesday, April 12, 2023 14

Available binary Combinations for Describing a Color

BitmapsBitmaps can be inserted by:

Using clip art galleries.Using bitmap software.Capturing and editing images.Scanning images.

ColorColor is a vital component of multimedia. Picking the right colors and combinations of colors for any multimedia project can involve many tries until you feel the result is right

Natural Light and Color:ROY G. BIV -> red, orange, yellow, green,

blue, indigo, and violet.

In additive color model, a color is created by combining colored light sources in three primary colors: red, green and blue (RGB). This is the process used for a TV or computer monitor.

Wednesday, April 12, 2023 17

Capturing and Editing ImagesCapturing and storing images directly

from the screen is another way to assemble images for multimedia.

The PRINT SCREEN button in Windows and COMMAND-CONTROL-SHIFT-4 keystroke on the Macintosh copies the screen image to the clipboard.

From there you can insert it into a paint program or other application.

Advanced Image EditingImage editing programs allow you to insert

and remove images from photosEnable you to alter and distort images, add

and delete elementsMorphing blends two images so that one

seems to “melt” into the other

Vector DrawingUsed for lines, rectangles, geometric

objects- stored mathematicallyCAD ( computed aided design) programs

created complex and geometric renderings needed by architects and engineers

Graphic artists use vector graphics to eliminate the “jaggies”

Programs for 3-D animation use vector graphics for rotation,spinning and shading

Image File Formats

Wednesday, April 12, 2023 21

Some software for creating images

Corel drawMS PaintAuto cad

Wednesday, April 12, 2023 22