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Portable Image File Viewer ENEE 408G: Multimedia Signal Processing Seun Fabayo John Glancy Gordon Krauthamer
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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
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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.
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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
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Connection Overview SERVERSCLIENT
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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
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Protocol SERVERCLIENT Wait for connection request Send Connection Request Send Command Wait for Connection acknowledgment Wait for command Send data packet 1 Receive data packet 1 Send acknowledgement Process data Wait for acknowledgement Send data packet 2 Write data Receive data packet 2
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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
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JPEG Compression The preferred format of the internet
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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
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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
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JPEG Encoder
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JPEG Decoder
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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
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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
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USER INTERFACE USER PROFILE
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Graphic Presentation: Shows name of project and members of the Team. Continue button: Goes to the next form. OPENING WINDOW
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PREVIEW 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.
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HELP WINDOW Close button: returns back to preview window. Help frame: shows how to operate the program.
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PREVIEW 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.
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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.
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USER PROFILE
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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.
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Portable Image File Viewer Demonstration
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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.
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