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Digital Imaging

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  1. Digital Imaging

  2. Three Major Steps • Input the photograph • Process the photograph • Output the photograph

  3. Input the Photograph • Digital still cameras - capture photographs in a digital format. • Scanners - convert printed photographs into digital photographs. Input devices for digital photographs include:

  4. Input the Photograph • Video cameras - capture images in a video format; use a frame grabber to isolate out individual frames and save them as still images. • Digital video cameras - sometimes can capture still images just like a digital still.

  5. Process the Photograph Once a photograph is in digital form, you can store it on your system and use a photo-editing program (such as Photoshop) to:

  6. Process the Photograph • Crop the photograph. • Change brightness and contrast to improve the image. • Use filters to adjust the image. • Reduce the number of pixels to make it smaller for posting on the Web or e-mailing. • Convert the photograph to another format.

  7. Output the Photograph • Some of the most popular ways to display digital photographs include: • Print the image on a color printer. • Insert the photograph into a word-processing or desktop publishing document.

  8. Output the Photograph • Post the photograph on a Web site. • Send the photo to a service on the Web for specialty printing onto T-shirts, posters, key rings, mouse pads, even cakes and cookies. • Store the photograph on your system for later use.

  9. Resolution • Low-resolution images (640 x 480) are good for small pictures (4 x 6) that don’t require a lot of detail. • Higher-resolution images (1024 x 768) are better for larger or more detailed pictures.

  10. Storage The number of images that you can store in a camera depends on a variety of factors including: • The capacity of the storage device (expressed in Megabytes). • The resolution at which the pictures are taken. • The amount of compression used.

  11. Storage The number of pictures you can store is important because once you reach the limit you have no choice but to quit taking pictures or erase some existing ones to make room for new ones.

  12. Storage Devices • Older and less expensive cameras have built-in fixed storage that can't be removed or increased. • Almost all newer digital cameras use some form of removable storage media. • Flash memory cards • Small hard disks • Floppy disk.

  13. Storage Devices • Flash memory cards consume little power, take up little space, are very rugged and easy to change. • They come in a variety of formats ( i.e., CompactFlash, SmartMedia, MemorySticks) that are not interchangeable.

  14. Transfer Method • Docking stations have a small base (to hold the camera) which is connected by cable to the computer. • Flash memory cards can be removed from the camera and plugged into the computer or printer to transfer the images. • Cameras with USB ports connect the camera to the computer with a thin cable.

  15. Transfer Method • Images stored directly onto a floppy do not require special cables. • Wireless infrared allows the camera to use a beam of infrared light to "point-and-shoot" images to a device located nearby. You can’t download images through walls or around corners.

  16. Compression • Lower compression results in high image quality and a large file size. • Greater compression produces poorer quality images with smaller file sizes. • When posting images on the Web, the image degradation isn't obvious, owever, enlarged prints reveal it quite clearly.

  17. Compression • Every time you open a JPEG file and then save it again, the image is compressed and becomes degraded. • Save your originals in a loss-free format such as TIFF at maximum color depth. • When you are finished editing, save the final version in the GIF or JPEG format.

  18. Digital Formats • JPEG (.JPG) • The JPEG (Joint Photographic Experts Group) format, pronounced "jay-peg," is by far the most popular format for the storage of photographic images and displaying them on the Web.

  19. Digital Formats • JPEG (.JPG) • Are best for photographic images (not text or line drawings). • JPEG supports 24-bit color (millions of colors). • Don't save JPEG images as JPEG images if you expect to modify them again later.

  20. Digital Formats • GIF (.GIF) • Supports only 256 colors. • Reduces the number of colors of color-rich image. • Best for text or line drawings.

  21. Digital Formats • TIFF (.TIF) • TIFF (Tag Image File Format) was originally developed to save images created by scanners, frame grabbers, and photo editing programs.

  22. Digital Formats • TIFF (.TIF) • Usually the best quality output from a digital camera. • TIFF format is widely accepted as an image transfer format and is widely used in desktop publishing applications. • TIFF files are not compressed and therefore may be large.

  23. Digital Formats • PSD, PSP, etc. • Are proprietary formats used by graphics programs. Photoshop's files have the PSD extension, while Paint Shop Pro files use PSP.

  24. Digital Formats • PSD, PSP, etc. • These are the preferred working formats as you edit images because they retain all the editing power of the programs. • Save your end result as a standard TIFF, JPG or GIF.

  25. Digital Formats for the Web • Currently, GIF and JPG are the formats used for nearly all web images. • TIFF is not supported by web browsers and should be avoided for web use. • Expect to see PNG replace GIF in the future.

  26. Selecting a Digital Camera When purchasing a digital camera it is important to consider the... • Ease of use • Quality of Resolution • Storage method and capacity • Transfer method

  27. Ease of Use • Who will use the camera? • How complex are the features? • Does it have a view finder? LCD display? • Is an adapter available? • Are the batteries rechargeable? • Is the instruction booklet easy to follow and understand?