Unit 3 Images and Graphics in Multimedia:

 3.1 Digital Image Representation:

Pixel-Based Representation:

• Definition: In multimedia, digital images are represented as a grid of pixels.
• Pixels: Smallest unit of an image, each holding color information.
• Resolution: The number of pixels determines the image's clarity and detail.

Color Models:

• RGB (Red, Green, Blue): Primary additive color model for multimedia images.
• CMYK (Cyan, Magenta, Yellow, Black): Used in printing for subtractive color mixing.
• HSB/HSV (Hue, Saturation, Brightness/Value): Represents color based on human perception.

Bit Depth:

• Definition: Bit depth determines the number of colors a pixel can represent.
• Higher Bit Depth: Allows for more colors and greater color accuracy in multimedia images.
• Grayscale vs. True Color: Grayscale uses 8 bits per pixel, while true color uses 24 or more.

3.2 Image and Graphics Formats:

Common Image Formats:

• JPEG (Joint Photographic Experts Group): Lossy compression for photographs, widely used in multimedia.
• PNG (Portable Network Graphics): Lossless compression, suitable for images with transparency.
• GIF (Graphics Interchange Format): Supports animation and simple graphics with lossless compression.

Vector Graphics:

• Definition: Represented by mathematical equations, scalable without loss of quality.
• Applications: Ideal for logos, icons, and illustrations in multimedia.
• SVG (Scalable Vector Graphics): An XML-based vector image format for multimedia web content.

3.3 Image Synthesis:

Computer-Generated Imagery (CGI):

• Definition: The creation of images with the aid of computers.
• 3D Rendering: CGI often involves rendering 3D models to create realistic images.
• Applications: Widely used in multimedia for special effects in movies, video games, and virtual environments.

Rendering Techniques:

• Ray Tracing: Simulates the path of light to create realistic lighting and reflections in multimedia.
• Rasterization: Converts 3D models into 2D images by determining which pixels to color.

3.4 Analysis and Transmission:

Image Analysis:

• Edge Detection: Identifying boundaries within an image for multimedia applications like object recognition.
• Color Histograms: Quantifying color distribution in multimedia images, aiding in analysis and processing.
• Feature Extraction: Identifying key features for multimedia applications like facial recognition.

Image Transmission:

• Compression Techniques: Reduce file size for efficient transmission in multimedia.
• JPEG Compression: Lossy compression suitable for photographs in multimedia.
• PNG Compression: Lossless compression for images with transparency.

Image Transmission Protocols:

• HTTP (Hypertext Transfer Protocol): Commonly used for transmitting images on the web.
• FTP (File Transfer Protocol): Used for the reliable transfer of multimedia image files between devices.

Multimedia Applications:

• Web Graphics: Images enhance the visual appeal of websites, utilizing various formats for efficient transmission.
• Digital Imaging: Medical imaging, satellite imagery, and scientific analysis involve complex image representation and transmission.
• Entertainment Industry: Image synthesis and transmission play a vital role in the creation of visually stunning multimedia content in movies, video games, and virtual reality.