portable image file viewer enee 408g: multimedia signal processing seun fabayo john glancy gordon...
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Portable Image File Viewer
ENEE 408G: Multimedia Signal ProcessingSeun FabayoJohn Glancy
Gordon Krauthamer
Overview
• Portable devices have become more and more popular in recent years.– Growth of wireless Internet applications– Remote access to files is becoming a greater
need
• Remote access to image files– Entertainment– Information– Job Related
Portable Image File Viewer
• A Client/Server Application that allows remote access to image files (bitmaps) on a server computer.– Allows connections to multiple servers providing
access to multiple databases of image files.– Implements JPEG image compression in order to
speed-up download time of files.– Allows remote scaling of files prior to sending in order
to reduce file size and download time if desired.
Networking
• Works as basic Client/Server application– Client: PocketPC– Server: Image Database
• Server database programs can run on a number of servers on the network
• Allows Client to connect to different server depending on desired application
Connection OverviewSERVERSCLIENT
Server
• Implemented in Java– Allows server program to run on any platform that has
a Java Virtual Machine
• Supported Functions– File List Refresh
• Get a list of files found on the Server
– Thumbnail Get• Get a thumbnail of a file on the file list
– File Get• Get a file on the file list
– Scaled File Get• Scale a file to the size of the screen before sending
Protocol
SERVERCLIENTWait for connection requestSend Connection Request
Send Command
Wait for Connection acknowledgment
Wait for command
Send data packet 1Receive data packet 1
Send acknowledgementProcess data
Wait for acknowledgement
Send data packet 2
Write data
Receive data packet 2
Networking Performance
• Maximum Achieved Transfer Rate = 0.5KB/sec
• Possible reasons– Slow internet connection– Slow transfer protocol
• Despite slow transfer rate, file is always received intact
JPEG Compression
The preferred format of the internet
Why JPEG?
• Reduced file size– 20:1 compression from bitmap files
• More color depth– 24 bits per pixel vs. 8 per pixel with GIF
• Result: 16 million colors vs. 256 colors
Disadvantages of JPEG
• Doesn’t handle black-and-white (but handles grayscale)
• Doesn’t handle motion pictures• “Lossy” compression – decompressed
image is different from original (However, it appears almost the same to human eyes, so this is only a problem when the image must be analyzed by machine)
• Takes longer to compress/decompress
JPEG Encoder
JPEG Decoder
S309Picturebox Control
• Handles JPEG files for eVB
• We used this control to:– Display JPEGs– Shrink JPEGs– Enlarge JPEGs
• Shortcomings:– Can’t write JPEGs– Can’t write pixels offscreen
Image processing functions of our program
• Displays full-size images from a server onto a Pocket PC
• Displays a thumbnail version of an image, if the user desires
• Scales the image to fit the screen, if the user desires
•USER INTERFACE
•USER PROFILE
Graphic Presentation:Shows name of project and members of the Team.
Continue button:Goes to the next form.
OPENING WINDOW
PREVIEW WINDOWPREVIEW WINDOW
Image list: shows the list of images from the server.
Preview frame: shows sample of an image in the list.
IP Address: takes the address of the server.
Disconnect button: disconnects from the server.
Help button
Display button: pulls up the display window.
Refresh button: reconnects to the server.
Connect button: connects to the server.
HELP WINDOW
Close button: returns back to preview window.
Help frame: shows how to operate the program.
PREVIEW WINDOWPREVIEW WINDOW
Image list: shows the list of images from the server.
Preview button: shows sample of an image in the list.
IP Address: takes the address of the server.
Disconnect button: disconnects from the server.
Help button
Display button: pulls up the display window.
Refresh button: reconnects to the server.
Connect button: connects to the server.
DISPLAY WINDOW
Image Frame: shows the final image.
Close button: closes the display window.
Shrink button: compresses the image to a smaller size.
Resize button: resizes the image to its original size.
•USER PROFILE
Final User Profile
• Users will mostly be between the ages of 18- 22 yrs.
• They will have the program operating on their PDAs or Cell phones.
• They will use the program on a weekly basis.
• Most will be college graduates, or enrolled in a higher institution.
Portable Image File Viewer Demonstration
Conclusion
• The Portable Image File Viewer provides an easy way for a Pocket PC user to gain access to image files on networked computers.
• JPEG encoding of files prior to transfer allows for faster download times without losing much quality.