Portable Image File Viewer ENEE 408G: Multimedia Signal Processing Seun Fabayo John 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 Overview SERVERSCLIENT

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 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

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 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 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 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.