Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 =...
Transcript of Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 =...
![Page 1: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/1.jpg)
Multimedia SystemsPart 5
Mahdi Vasighiwww.iasbs.ac.ir/~vasighi
Department of Computer Science and Information Technology,Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
![Page 2: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/2.jpg)
Image Formats
PNGo Portable Network Graphicso Developed in early 1995 as an alternative to GIFo Three advantages over GIF
• Alpha channel (up to 16 bits) • Gamma correction• 2D Interlacing
![Page 3: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/3.jpg)
Image Formats - PNG
Interlacingo Adam7 algorithm
• operates in both dimensions • uses seven passes and through each 8 × 8 block of
an image
![Page 4: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/4.jpg)
Image Formats - PNG
Interlacing
Pass 1 1/64 = 1.5625%
Pass 2 1/32 = 3.125%
Pass 3 1/16 = 6.25%
Pass 4 1/8 = 12.5%
Pass 5 1/4 = 25%
Pass 61/2 = 50%
Pass 7, 1/1 = 100%
![Page 5: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/5.jpg)
Image Formats - PNG
ADAM7 Pass 4 1/8 = 12.5%
PNG
Interlacing
GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are 2-to-1
Row-wised Pass 1 1/8 = 12.5%
GIF
![Page 6: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/6.jpg)
Image Formats - PNG
ADAM7 Pass 5 1/4 = 25%
PNG
Interlacing
GIF pixels have an 4-to-1 aspect ratio, whereas PNG pixels are 1-to-1
Row-wised Pass 2 1/4 = 25%
GIF
![Page 7: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/7.jpg)
Image Formats - PNG
PNG GIFinterlacing interlacing
![Page 8: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/8.jpg)
PNG• Supports up to 16 bits per pixel in each color channel• Supports lossless compression• Does not support multiple image format/ animation
like GIF
• embedded textual information • title• author's name • description
Image Formats - PNG
![Page 9: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/9.jpg)
Image Formats
JPEG• Standard method of compressing photographic • Widely used image format• Joint Photographic Experts Group• Compression is lossy
• allows the user to set a desired level of quality
• For a Quality factor 75%, JPEG achieves image size around 6% of original size
![Page 10: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/10.jpg)
Image Formats - JPEG
Preprocessing
JPEG
1. partition the image into blocks of size 8 x 8 pixels
2. subtract 127 from each pixel intensity in each block
![Page 11: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/11.jpg)
JPEG
Image Formats - JPEG
Preprocessing
Transformation
Discrete Cosine Transformation
DCT
![Page 12: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/12.jpg)
JPEG
Image Formats - JPEG
Preprocessing
Transformation
Quantization
make decisions about values in thetransformed image
• elements near zero will converted tozero
• All quantized values will then berounded to nearest integers.
![Page 13: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/13.jpg)
JPEG
Preprocessing
Transformation
Quantization
Image Formats - JPEG
quantization matrix for a quality of 50%
![Page 14: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/14.jpg)
JPEG
Image Formats - JPEG
Preprocessing
Transformation
Quantization
• Huffman coding algorithm
The original image:1602408 = 307,200 bits
Coded image:85,143 bits
~70% less storage space than that of theoriginal image!
Encoding
Original Compressed
![Page 15: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/15.jpg)
Image Formats - JPEG
JPEG
Issues and Problems• Decoupling• Loss of information Original
Compressed
![Page 16: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/16.jpg)
Image Formats - JPEG
JPEG
What about colors?
• convert the RGB space channels to YCbCr space
• each color component as would be compressed as a separate image.
![Page 17: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/17.jpg)
Image Formats
TIFF
• Tagged Image File Format • Developed by Aldus Corporation in the 1980s• Support for attachment of additional info. (Tag)• was originally a lossless format• platform independent• universal to software programs• can store many different types of images• are divided into sections with a different data type
![Page 18: Multimedia Systemsvasighi/courses/multimed1.96/multi.sys1...Image Formats -PNG ADAM7 Pass 4 1/8 = 12.5% PNG Interlacing GIF pixels have an 8-to-1 aspect ratio, whereas PNG pixels are](https://reader033.fdocuments.in/reader033/viewer/2022042216/5ebe3938f09b1e400d536759/html5/thumbnails/18.jpg)
Image Formats
Other formats
• EXIF (Exchange Image File)• WMF (Windows Meta File)• BMP (BitMaP)• PTM (Polynomial Texture Mapping)