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Attaching Photographs to Employee Records in Your Database
(August 14, 2000) If you are reading this bulletin you are probably interested in linking employee photographs to records in your Skills Manager and/or Training Manager Academy database. You may have previous imaging experience or this may be your first exposure to digital imaging. This bulletin provides information and guidelines that will help make your experience with photographs a successful one.
Photographs must be digitized to be usable by a computer. That simply
means that the photos must be converted to an electronic
(digital) format that the computer can work with. This
process requires a hardware device (scanner, digital camera,
etc.) and/or software capable of manipulating the digitized photos.
Nearly all imaging devices come bundled with
software for editing and organizing photographs.
Capturing, editing, and attaching photos to employee records can be
a time consuming process. You
should know some basics about image quality and size before you
begin. There are many factors that
can affect image quality and size.
Nearly all of these factors can be controlled either from your
hardware device or imaging software.
Take a look at the following examples and you will see how image size can
affect memory usage.
We
recently spoke with one customer who said their digital camera had a handy
email setting which produced images with a quality and image size that works efficiently in e-mail attachments and in software applications
like Skills Manager and Training Manager Academy. We
assisted another customer who was concerned about the size of their
Skills Manager photo
table, which was over 100MB in size and growing rapidly.
They had scanned and attached only 1,100 photos to employee records
in the Skills Manager database and already the file was huge, and they
still had several thousand photographs
to go.
They also noticed that some employee records displayed quickly
while others exhibited a considerable delay in display time.
We took a look at their photo files and discovered that the average size of just one photo was 91KB, or larger than
recommended.
After further investigation we discovered that
initially they had done a terrific job of scanning photos in the 5KB to
25KB range, however after purchasing a new scanner the image size
increased to over 1MB per photo.
(At that size you can fit just 100 photos per 100MB).
Much more time is required for a network server to retrieve a 1MB
image file from disk, send it down the network wire, and render it into
the workstation memory than is required for smaller images.
The customer was experiencing a delay in display time due to their
oversized images. The customer quickly adjusted some parameters in their imaging
software and things improved considerably. The
following is an excerpt from the Skills Manager help text.
It briefly describes the various issues one must consider when
capturing digital photographs. Employee
Photographs
Multimedia
files such as graphics, video and sound can fill a disk drive quickly.
There are some things that you can do to make efficient use of
computer storage when working with graphics files such as digital
photographs.
Several factors affect storage requirements, the most prominent of
these are image size, resolution, number of colors, and file
type.
Nearly all digital imaging devices such as scanners and cameras are
delivered with imaging software that can alter the characteristics of
captured images. Image
Size
The
size of an image has a direct impact on storage requirements.
Simply put, the larger the image, the more memory required to store
it.
The photograph feature in Skills Manager does not require a large
photograph due to the small display area used on the employee entry form.
In fact, using a large photograph actually has a negative effect on
display quality (because of scaling) and will take longer for the computer
to retrieve it from the disk and render it on the monitor. A
large photograph will however work with the application because of the
scaling capability of the software.
For example, a 4" x 5" photograph will be scaled down to
fit the display area on the employee form and in the process some of the
picture data is discarded.
(The stored image is unaffected).
While contemporary cameras can easily produce individual photos that
require 2 or 3 megabytes of memory, this is not practical when the photos will be used with Skills
Manager. Recommendation:
When scanning photos or capturing them from digital cameras, lower the
image size prior to saving them to disk to reduce file size.
Reduce the size of a 4" x 5" photo by a factor of two to
create a 2" x 2 1/2" image, which will still work great with
Skills Manager. Resolution
Resolution
determines the pixel density of an image.
(Pixels are the little dots that constitute an image on a computer
monitor or computer printed page).
Resolution is commonly described in terms of dots per inch (dpi) or
pixels per inch (ppi).
The default resolution on most digital imaging devices such as
scanners and cameras is currently 300 dpi or 600 dpi.
This resolution is probably excessive for the Skills Manager
application. Recommendation:
Scanning at 100 to 150 dpi should be sufficient.
Higher densities will work but they also increase file size. Number
of Colors
Every
digital image, whether monochrome, grayscale, or full color contains data
defining the colors used in the image.
The number of colors supported in an image is reflected in the
physical size of the file.
A color image with only a 16-color palette is considerably smaller
than the same image at 256 colors.
The same image with 32,000 colors (24 bit) would be still larger
and one with 16 million colors (32 bit) would be very large in comparison. Recommendation: Graphics
File Type
There
are many graphics file specifications used in the computer industry.
Most of these were engineered by corporations which developed
graphic software applications that needed an efficient medium for storing the graphic
data created by their software.
A number of such software applications achieved such market share
that the associated graphic file type was adopted industry wide as a
standard format for exchanging graphic data between other software
applications.
Each specification has strengths and weaknesses.
Some compress data extremely well but lose image quality while others have great image quality but
also create larger file sizes. Recommendation:
The Skills Manager photograph feature supports several graphics file types
including, .bmp, .gif, .jpg, .pcx, and .wmf.
The JPEG specification, developed by the Joint Photographers
Experts Group specifically for working with photographs, is especially
effective at compressing images with large color palettes to small file
sizes.
Graphics files using this specification are easily identified by
the .jpg extension in the file name. Summary
You
will need to experiment with the settings in your software until you find
the settings that will provide acceptable quality and efficient memory usage.
Applying these simple guidelines when capturing photographs for use with Skills Manager will result in reduced storage
requirements and speedier display times. We hope you have found this advice helpful. Happy Imaging! by
Steve
Wesner Crown
Pointe Technologies |
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Copyright ©2002 Crown Pointe Technologies, Inc.
All rights reserved.
