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Digital Image Processing #HW1. Extraction of Bitmap Header File Manipulation of Image Pixel Information. Contact Information Tzu- Jui Wang ( 王子睿 ) V isual C ommunications Lab Dep. of Communications Engineering, N ational C entral U niversity - PowerPoint PPT Presentation
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Digital Image Processing #HW1-Extraction of Bitmap Header File
-Manipulation of Image Pixel Information
Contact Information
Tzu-Jui Wang (王子睿 ) Visual Communications Lab Dep. of Communications Engineering, National Central University No.300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan (R.O.C.) Phone: +886958801691 E-mail: juliuswang0728@gmail.com
Outline• Reference• Work Flow• Introduction to Bitmap File• Homework Details– Extract Header File– Construct Histogram– Extract Region of Interest with Specified Coordinate
Set• Grading Policy• Demo Schedule
Reference• A Beginners Guide To Bitmaps, – http://local.wasp.uwa.edu.au/~pbourke/dataformats/
bitmaps/
– http://atlc.sourceforge.net/bmp.html
• Data type in Computer, wiki resources, – http://en.wikipedia.org/wiki/Integer_(computer_scien
ce)Those might be useful !
Work Flow
Extract region of interest
Input coordinate set(xi, yi), i=1,..,4 of
bounding box
(x1,y1) (x2,y2)
(x3,y4) (x4,y4)
Extract header information
Construct histogram on R, G, B channels, respectively
Extract pixel information
24-bit 8-bit
Introduction to Bitmap File (1/2)Bitmap File Header
Identifier (ID) 2File Size 4
Reserved 4Bitmap Data Offset 4
Bitmap Info HeaderBitmap Header Size 4
Width 4Height 4Planes 2
Bits Per Pixel 2Compression 4
Bitmap Data Size 4H-Resolution 4V-Resolution 4Used Colors 4
Important Colors 4Color Table (Palette)
Palette N*4Bitmap Array
Bitmap Data N/A
File header(14 bytes)
Info header(50 bytes)
Header file(Image profile)
Image content Pixel information
i.e. a 8-bit image, N = 28
Empty for 24-bit image
Introduction to Bitmap File (2/2)
Header + Color paletteHeader54 bytes
54 bytes +1024 bytes
Image content
Image content
24-bit lena.bmp 8-bit lena.bmp
Construct Histogram• Histogram on R, G, B channels
Figure1: beatles.bmp Figure2: RGB histogram
FrequencyPixel value
Extract Region of Interest with Specified Coordinate Set
• Suppose given (x1, y1), (x2, y2), (x3, y3), (x4, y4)– The bounding box will be as followed
(x1,y1)
(x2,y2)
(x3,y3)(x4,y4)
Bounding box
Final output
Grading Policy – Code & Demo (80%)• Everyone will be asked few questions.• Extract Header File (20%)– We’ll test your system with images except lovely Lena.
• Construct Histogram (30%)– Same as the above.
• Extract Region of Interest with Specified Coordinate Set (30%)– Arbitrarily give four coordinates, and create a new
bitmap file with extracted region.
Grading Policy – Report (20%)• Report (20%)– Plot all your experimental results. (10%)– Depict the .bmp format as clear as possible. (5%)– Describe your findings as rich as possible. (5%)
• We don’t force you to write down how you feel about this homework. But, you can still show it up.– Too trivial, too hard, …too ?– You can describe any difficulty you’ve encountered.
Demo Time• Demo time will be at 2010.10.07, begin around
7:00 pm (2 weeks later) at R3-307 (VCLab).
• Demo orders will be announced later, 5 minutes for each, please refer TA’s website.– http://
140.115.156.251/vclab/html/course/DIP2010.html– Bring your codes and report.– No delay is allowed except a special cause.
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