| What's
the difference between raster and vector files? |
| |
A raster image is roughly
equivalent to a newspaper photograph. If you look closely
you see that it is made up of lots of small dots. The
density of these dots is referred to by resolution,
measured in dots per inch (stated as 'dpi'). Raster files
are stored in many file formats. TIFF is a common example.
Vectors are used to describe specific
objects defining their size, position and geometry. The
image seen on screen in a CAD application is only a visual
representation of the vector file. The vector information
in a CAD file is mathematical. It is not stored as an
image.
So, for example, a vector line is an
absolute line connecting two or more points; a vector
curve is described by source coordinates, a polynomial
equation and end point coordinates.
Vector information is stored in many
different file formats, one of which is DXF. The primary
function of the DXF file is to permit CAD vector
information to be exchanged between different CAD
applications.
|
| Do
scans work in a CAD program? |
|
Scanners produce raster
images, not the vectors used in CAD programs. When CAD
software allows import of a raster, it will display it as
a raster (i.e. dot based) image within the CAD document.
The lines in a raster image in a CAD document
cannot be manipulated in the CAD program. The CAD program
will not convert it to vectors unless assisted by a
conversion program like TracTrix.
|
| How
can I use my desktop scanner to create CAD files? |
|
Paper to CAD (raster to
vector) software such as TracTrix take your scans, convert
them to vectors and output them as a DWG, DXF, IGES, HPGL
or other vector file format. In the case of TracTrix this
can be done within AutoCAD itself or outside of AutoCAD.
|
| What's
the difference between pixels and dots per inch? Is a dot
a pixel? |
|
A pixel is a minute
circular point of light about 10 or 12 thousandths of an
inch in diameter (sometimes stated as 10 or 12 'mils')
created on a monitor screen.
A dot is a sample taken by a scanner for
representation in a raster image. A 300 dots per inch
(dpi) scan takes snapshots of dots which are about 3 mils
across (3,33333....mils to be exact). To
represent a 300 dpi scan on screen at a 1:1 scale your
computer typically has to consolidate groups of 16 dots
(each 3.33... mils diameter) into a single pixel (10 - 12
mils diameter)
This means that the raster image you see
on screen is only an approximation of the underlying
digital 'dpi' information from your scan. And your scan
itself is an approximation. Sometimes the screen
appearance can be disconcerting.
|
| Why
can't I just edit my raster files and not have to bother
taking them to vector? |
|
Raster files are excellent
for visual purposes, for Web posting and distribution, for
archiving and for security in release control (see Trix
RasterServer) -
after all they are a picture of the original image just
like a print. TracTrix does provide raster editing tools
so you can edit and clean up your scans. But raster
editing can be tedious if there are considerable
modifications to be done - especially if you are used to
the power of a CAD package.
And all CAD software uses vector objects
instead of rasters. The primary benefits are ability to
precisely describe, create, scale and manipulate
individual objects.
|
| In
image resolution, what's the difference between 400 dpi
true and 400 dpi interpolated? |
|
True resolution is the
number of dots per inch of reflected light captured by the
scanner head. The scanner head is physically limited in
the number of dots which it can capture.
Interpolation software (usually built in
to the scanner, but also available in raster manipulation
programs) can make a good guess at what lies between the
dots recorded by the scanner.
By comparing adjacent dots captured in a true 200 dpi scan
interpolation software might replace each dot with four
new ones (creating a 400 dpi interpolation) or even nine
new ones (creating a 600 dpi interpolation).
For many applications (including the
majority of paper to CAD conversions) interpolation works
well. But interpolation will never be as accurate as a
true resolution.
|
| Is
there an international standard for vectorization? |
|
No. But conversion of
paper to CAD and indexed raster images may provide you and
your organization with an excellent opportunity to begin
implementing ISO 9000 quality standards.
A good engineering document management
system goes a long way towards meeting the ISO standard.
See Trix
Organizer.
|
| I've
too many drawings to vectorize in-house. How should I
choose a conversion bureau such as the one run by Trix
Systems? |
|
There is a pretty clear
relationship between price and quality in bureau
conversion. We recommend starting with a pilot project
comprising two stages. In the first stage establish that
the bureau can deliver to your required quality for a
small sample of drawings, say five or ten.
From this limited experiment set the
parameters for a second stage test with a much larger
sample of your drawings (maybe 5% of your stock). The
second stage determines how your bureau will perform under
a real load.
You and your bureau can establish a
solid relationship during this test and sort out potential
problems. And most important, involve your eventual users
in the test. Have them check that the quality meets their
needs. Some users may need help in defining their needs.
You might want to think about an alternative to
vectorizing all of your drawings. That is to scan all of
your drawings and vectorize later as required. Trix
Systems does offer quality-guaranteed Trix
Systems Conversion Services.
. |
| If
I have a small or hand-held scanner, can I scan a big
drawing in pieces and 'stitch' them together afterwards? |
|
If you have access to a
large format scanner use it instead of stitching small
images together. TracTrix 2000 can convert very large
drawings (E/A0 and above). Many areas have copy shops or
similar reproduction shops where a large document can be
scanned to disk without editing at very reasonable prices.
For instance a busy 'E' size drawing
scanned at 300 dpi monochrome (black and white) can be
stored on a 3 1/2" diskette or emailed to you from
your scanning bureau. The raster file on disk can then be
vectorized in TracTrix at your convenience. Do be sure
that your bureaus understands the level of quality and
resolution you require before they scan the drawings.
Vector output is only as good as the raster input. Advice
on how to scan for best results is included in TracTrix
manuals.
|
| What
should I be aware of before I start converting images to
CAD? |
|
Vectorizing
packages do not add information to your original drawing.
We tend to think of drawings as being super accurate. This
is not true. An
image on paper is imperfect, inaccurate and imprecise.
This may seem like a heresy to all who (like us) have
slaved over drawing boards. Think about what we do when we
'read' a drawing:
Our intellect works wonders piecing
together the disparate pieces of information which our
eyes pick up from a drawing; Our brain automatically sorts
text from line work and combines different sorts of
visible information into a comprehensive whole. With this
we can mill our piece, set our forms, etc. to the
designer's requirement.
Contrast this with CAD. When we work in
a CAD package vector information is created. The
dimensions are the primary information and the CAD package
produces a visible representation on screen (or to a
plotter) based on these dimensions. This output is an
approximation from the absolute dimensions of CAD. We go
through the same processes to begin milling or setting up
our formwork. And whether the information began in CAD or
on a drawing board, we adjust it to the accuracy needs and
limitations of the real physical world.
|
| What
are my options when considering how to get from paper to
CAD? |
|
There are several methods
that will help you take a paper drawing or print into CAD.
You could simply redraw from scratch in a CAD program, you
could create a vector file from the drawing on a
digitizing tablet, you could scan the drawing, open it in
a 'Head-up' digitizing program on your monitor and
digitize to vectors with a mouse much like the digitizing
tablet or you can use an automatic raster-to-vector
program like TracTrix.
Tablet and head-up digitizing is
subject to the skill and eye-hand coordination of the
operator. Studies have shown that as digitizing operators
tend to wander off the original lines by as much as 1/32
of an inch as they progress through a days work. Automatic
raster-to-vector conversion will provide you with editable
vectors in a fraction of the time of other methods.
|
| So
what's the process involved in translating paper to CAD? |
|
It always requires two
stages. In the first you scan and convert a raster image
of the original drawing to CAD vectors . In the second,
you check that the CAD representation created by
vectorizing meets your need for accuracy and purpose.
You've probably heard the expression
"garbage in, garbage out". This is not more true
than scanning a paper drawing and vectorizing it.
Vectorizing software can only make vectors where there is
raster information for it to track.
Breaks in the lines, poorly connected lines at corners,
blobs in the image at multiple line intersections and
similar imperfections in the raster image all contribute
to imperfect vectors.
TracTrix is used by a major prosthetics
manufacturer to create cutting and drilling templates for
microsurgery. Their originals are very finely detailed.
Generally, the accuracy you'll achieve will depend
primarily on the quality of the original drawing. Accuracy
can then be made absolute in whatever CAD software you are
using.
You should always expect to take raster
images automatically to vectors and then edit them to the
precision your application requires.
|
| What
else should I be aware of when considering paper to CAD
conversion? |
|
Manipulating large image
files is best done with plenty of RAM. For example, a 300
dpi scan of a B size (11 X 17) drawing will create an
uncompressed file that is nearly 17 Megabytes. RAM
therefore is an important consideration when converting
and manipulating image files. At least 32 or even better
64 meg of RAM is recommended for paper to CAD conversion.
|
| How
about drawings that have been reduced to a smaller size? |
|
When large drawings are
reduced to a smaller size (using the 'reduce' function on
a scanner or copier) lines and details tend to bleed
together into indiscernible blobs of pixels. Parallel
lines that are close together blend into one line. Small
holes in the original drawing close up to a solid black
object. TracTrix cannot 'read' through these solid black
objects to figure out what they are. Therefore we do not
recommend reduced size drawings as a starting point for
automatic raster-to-vector conversion.
|
| What
is the difference between accuracy and precision in
vectorizing |
|
Repeating the point above:
Scanning paper to create a raster image does not improve
the quality in any way. As a matter of fact the scan is a
less perfect than the original. Vectorizing software of
any type can only vectorize that which it can 'see', the
pixels in the raster image. The resultant vectors are no
more perfect than the raster.
Vectorizing is accurate to the extent
that the vectors are an accurate representation of the
raster image. Is this 'accuracy' good enough for your
application? Perhaps. But if it isn't, the vectors can be
edited to make the vector file as precise as you require.
Remember, vectors can be made to be mathematically
perfect, rasters cannot.
|
| Does
high resolution (dpi) assure vector accuracy? |
|
TracTrix follows either
the centerline on lines or the outline of images. It
achieves this by looking for pixels. In centerline
tracking, TracTrix looks for the chosen line width by
looking at pixel quantities across line and seeks the mean
center of the line. Having more pixels from a higher
resolution will not necessarily create a
"better" mean centerline.
When following an outline it looks for
pixels on the edge of the image. Higher resolution might
present a 'smoother' less jagged edge for TracTrix to
vectorize but the vectors are not more accurately created.
Higher resolution makes for bigger files
to manipulate. Bigger files require more pre-processing
storage and processing takes much longer (twice the
resolution means four times as many pixels to store and
process).
As a general rule, there are rapidly
diminishing returns from increasing resolution for raster
to vector conversion. We tend to use 300 dpi or 400 dpi.
Occasionally we need 600 dpi for small, finely detailed,
originals.
|
| Horizontal
and vertical vector lines on screen do not appear to be
straight, but they were in the original drawing. Why? |
|
What you see on screen is
only a visual display of the actual stored CAD file and
does not represent what the file will create on a plotter
or printer. The vector points, also seen on screen, more
accurately depict the vectors as they will be plotted.
What you are seeing is the result of a slightly askew
scan.
When a computer depicts straight lines
on screen they will appear straight, without a jagged
appearance, only when they are absolutely square to the
screen's matrix. That is if they are perfectly parallel to
or at right angles to the horizontal scan of the monitor
If they are slightly off square the
computer tells the screen to depict the straight line as a
Cathode Ray Tube scan series which might be: Fill 100
pixels horizontally, go down 1 pixel, fill 100 pixels
horizontally, etc.
It is this small one or two pixel step
down which makes straight lines appear to have a jog or
appear jagged on screen. The underlying vector which it is
representing is a single point-to-point line.
Consider the jogs to be an optical
aberration on the monitor screen and not representative of
the actual vector. In TracTrix, one can see the actual
vector points at each end of the line by clicking on the
line.
|
| How
come some vector files are bigger than raster files of the
same image? |
|
The raster image size is
based upon the resolution (dpi) and the physical size of
the image. The vector file size is based upon the number
of vector entities required to represent the raster file.
The relationship between the two varies with the content
of the drawings, the entity types in the vector file, the
raster format used and whether there is compression in the
raster format.
|
| My
drawings are already in CAD. How do I publish them
electronically around my company? |
|
After more than a decade
of building engineering document management systems it is
clear to us that raster file formats are the most secure,
tamper-proof, durable and easiest method for publishing
and archiving CAD designs. For some of the reasons take a
look at our Trix
RasterServer
page.
In brief: Raster formats such as TIFF,
CALS and C4 are non-proprietary, stable - you won't have
to buy 'upgrades' every couple of years, and viewable and
printable from a wide variety of viewing software.
|
| How
can I publish engineering drawings on the Internet? |
|
The simplest method is to
rasterize completed CAD designs from DWG or DXF to a
raster format that can be viewed by a Web Browser. These
formats are PNG, JPEG or GIF. These can be published using
the regular IMG tag in HTML. TracTrix
and Trix
RasterServer
produce the PNG format for this purpose. The user needs
nothing more than a recent Web Browsing software.
If you have large, complex, files and/or
you want to do more than just view a drawing through a
Browser you should look at adding a viewer plug-in to the
users' Browsers. Plug-ins add functionality to a Browser.
For example, Trix Systems offers a Plug-in version of Trix
DrawingCenter.
When this is installed a user can view DXF. DWG, HPGL and
many raster file formats. The publisher does not have to
convert these to PNG, JPEG or GIF. In addition to viewing
the plug-in provides annotation, measuring tools, printing
and saving controls. The user can add additional
information to a copy of drawing and save it at the local
workstation.
Other companies also offer plug-in
viewers. There is an AutoCAD specific DWF format which
also requires a plug-in. The PDF format is also for Web
publishing using Acrobat Reader as the plug-in for
Browsers. TracTrix 2000 and Trix RasterServer also convert
CAD formats to PDF files.
|
Questions
specific to TracTrix Software
|
| What
is the typical TracTrix Paper to CAD conversion process? |
|
Scan your original into
TracTrix. Select the description which fits your type of
drawing from pre-defined types (e.g. architectural,
contour, illustration, logo, mechanical). Select the
portion of the drawing to convert. TracTrix then
automatically processes the raster lines into vectors.
Compare the vectors with the underlying original raster
image and make any post-processing changes using TracTrix'
built-in vector editing tools. Export the result in the
vector format of your choice.
|
| Speed/Expectations |
|
TracTrix can convert a
busy E-sized drawing in about 1 minutes on a reasonably
modern CPU.
In our years of providing image
conversion for customers we have learned that individual
needs are unique. So we are reluctant to suggest exactly
what savings TracTrix can bring you. But based on the tens
of thousands of drawings that we've converted in our own
conversion bureau, we'd hazard a guess that after building
in post-processing clean-up you could aim for 50% savings
in hours spent on conversion.
That's not to say that all drawings lend
themselves to raster-to-vector conversion. Depending on
quality and intended application, you'll find some
drawings can be almost entirely vectorized using TracTrix,
others may inevitably require manual redrawing.
TracTrix is very forgiving in that the vectors created can
be deleted and re-vectorized, edited and all vector errors
corrected before saving in the CAD file format of your
choice.
|
| Will
TracTrix give me a DWG file? |
|
Yes.
TracTrix 2000 software also generates
DXF, IGES and other vector description files which import
into virtually all CAD packages. After you have imported
the DXF, or IGES file into your CAD package you have a CAD
document on your screen. When you open and save this from
within whatever CAD program you have it creates the native
CAD file for your CAD package.
|
|
. |
| Do
I have to use TracTrix to drive my scanner, or will any
image file work? |
|
TracTrix can start with a
raster image file from many different sources. Your, or
your vendor's or your bureau's scanner(s) will produce a
raster image file which TracTrix can work with. Digital
cameras, scans from aperture cards and film are all raster
files that TracTrix can convert. TracTrix also includes a
TWAIN driver and large format scanner drivers to directly
scan images into TracTrix.
|
| What
raster and vector formats does TracTrix work with? |
|
Depending on version of
TracTrix used, TracTrix can import
ATT, BMP, BRK, CALS-Group 4 Type 1, CALS-Group
4 Type 2, CLP, CUT, DCX, DIB, GEM IMG, GX2, GTX G3, GTX
G4, ICA, ICO, IFF, JEDMICS C4, JPEG, KFX, LV, PCX, MAC,
MSP, PCD-Photo CD, PICT, PCX, PSD-Photoshop, RAS, TGA,
TIFF- Pack Bits, TIFF-Modified Huffman, TIFF-Group III,
TIFF-Group IV, TIFF-JPEG, WMF, WPG, XPM, XBM, XWD.
Depending on version of TracTrix used,
TracTrix exports DWG/DXF (R12, R13, R14, 2000), DRW, EPS
(AI-88), HPGL, IGES (4.0 and 5.1 - 112 or 126 entity), WMF
and TIX formats.
|
| How
do I convert CAD files to non-CAD files for archiving or
distribution? |
|
TracTrix 2000 can
individually convert DWG, DXF and HPGL CAD files to
high-resolution raster files. For batch conversion
consider Trix
RasterServer.
|
| Is
TracTrix a scanner? |
|
TracTrix is software. It
does not include hardware. TracTrix can either drive or
use the raster output from practically every scanner
available. If you do not have a scanner you will need to
acquire one to run TracTrix (unless you plan to use a
bureau for your scanning). Plan to purchase a scanner
which generates at least 300 dots per inch resolution and
if a small format scanner preferably one that supports the
TWAIN interface. TracTrix also drives several large format
scanners including, Contex, Ideal, Vemco, CalComp, Océ
and WideCom. You should also look for a scanner which also
scans and outputs in color so that you can take advantage
of TracTrix vectorization from colored originals.
|
| I
have an old scanner. Will it work with TracTrix? |
|
If your scanner can create
a monochrome (also called bi-tonal or black and white -
i.e. no shades of gray) TIFF, CALS or one of many other
monochrome image file formats you can use TracTrix.
To use TracTrix color vectorization
you'll need a color scanner.
|
| Is
there any way I can use TracTrix without a scanner? |
|
The short answer is that
TracTrix requires the type of image that scanners create.
A more complete answer is that you do not need to own or
acquire a scanner in order to use TracTrix.
You could go to a scanning bureau to have your scans done.
Or you could try using your fax modem, although we don't
recommend this approach.
Conversion Bureaus: You could
have your drawings scanned at a bureau, put the images on
disk, tape or CD ROM and use these stored raster images as
input to TracTrix.
A disadvantage of this approach is that
you will not be able to experiment easily with scanning
difficult images - dirty, dilapidated or cluttered ones -
so that they vectorize optimally.
You and your bureau should establish
clear quality control procedures for the scans, preferably
after running a pilot study using a good sample of your
drawings. Alternatively, for large conversion projects,
you may want to consider contracting out all the work to a
conversion bureau. Trix Systems does offer a conversion
service. See Trix
Systems Conversion Services.
Legacy Scans: If you already have
stored binary images from previous scans, they can
probably be taken into TracTrix with no problem. Some
experimenting may have to be done to achieve this. For
additional help with poor quality images ask us for
advice.
Aperture cards: Few companies
have an aperture card scanner. But many have aperture
cards and an aperture card viewer. Aperture cards can be
scanned by a bureau and the raster file delivered to you
on disk or tape. These files can then be opened and
converted by TracTrix.
Using a Fax image: We know of
users who fax drawings to their computer's fax modem
(using the fine setting) and open the stored fax image in
TracTrix to create vectors. However we don't recommend
this approach. TracTrix works best with images of at least
300 dots per inch or 400 dots per inch. Normal fax
standards do not support this level of resolution.
|
| What
will I save by using TracTrix? |
|
Exact savings depend upon
the quality of the original drawing and the type of image
being brought into CAD. Some users report costs savings as
high as 80% against conventional methods such as complete
redraws, tablet digitizing and heads-up digitizing. And
for some images, such as contours, automatic vectorization
by TracTrix saves even more.
Taken over a library of original
drawings we think you might realistically expect that the
total time required to scan, vectorize with TracTrix and
perform post-conversion tidy-up would be around 50% of
what it would take for manual redrawing in CAD. However,
every user's originals are different.
|
| What
will I gain by using TracTrix? |
|
This question is a bit
different from 'What will I save..? TracTrix has opened
new methods to the 'time to market' issues so important to
today's manufacturers. Many companies employ TracTrix to
shorten time to manufacture by allowing sketches and other
irregular drawings to be rapidly taken into CAD format for
use in numerically controlled milling machines, machining
centers, laser, water jet and plasma arc cutters.
Manufacturers are able to start with
less than perfect originals and use TracTrix technology to
produce samples and finished parts in a fraction of the
time previously taken.
|
| What
does TracTrix do with text, symbols - Optical Character
Recognition (OCR) ? |
|
From our experience, text
on engineering drawings, especially numerals and angled
text, is very difficult to capture adequately with
conventional OCR technology.
Hand drawn letters and numerals often
look alike and are very difficult for the eye to discern.
For example, we find that the hand drawn 'B' and '8' are
quite frequently mistranslated, a poorly formed capital
letter 'G' is often mistranslated as a '6' and vice versa.
Text at any significant angle to the normal axes is missed
entirely. Post OCR editing time to find and correct the
things that were missed or worse, erroneously translated,
often takes longer than keying in all the text. The
comments for text apply equally to symbols.
TracTrix 2000 has a unique text
recognition technology. When initiated it searches for
text regions and isolates them from the drawing line work
itself.
The text recognition in TracTrix 2000 will either convert
the identified text regions to CAD characters by its built
in OCR or allow you to 'train' it to recognize the
uniqueness of the characters in your particular drawing or
set of drawings.
If font-based text is not a requirement, text areas can be
selected for vectorization using TracTrix outline mode.
This produces very readable text in vector lines rather
than a vector font.
Alternatively, if the text is too
unreadable to convert automatically TracTrix 2000 provides
tools to create font-based vector text. In TracTrix 2000
the user manually enters the text in vector overlay mode,
then deletes the raster text underneath.
Trix Systems is continuously reviewing
OCR and pattern recognition technology in order to improve
and enhance TracTrix 2000. Recognition of shapes is not
yet available - this 'pattern recognition problem is
similar to that encountered with OCR - but the techniques
available for our present processors are just not
satisfactory.
|
| Can
I just vectorize what I want and not the whole drawing? |
|
Yes. TracTrix allows
"windowing" around that portion you wish to
vectorize.
|
| Does
TracTrix despeckle or eliminate "noise"? |
|
Despeckling or noise
elimination means eliminating small groups of pixels which
create visual 'dirt' or visual clutter in a raster image.
TracTrix settings allow the user to define the minimum
size of object to be vectorized. In this way 'dirt' is
ignored and not vectorized.
|
| Does
TracTrix do orthogonal adjustment? |
|
Squaring up corners is
referred to as orthogonal adjustment. TracTrix provides
this facility. It also allows you to adjust the whole of
or parts of a vector image to be absolutely vertical or
horizontal.
|
| Does
TracTrix 2000 recognize circles? |
|
TracTrix recognizes
circles as well as arcs, lines, polylines and Bezier
curves.
|
| How
far can TracTrix zoom in? |
|
It can zoom enough so that
the user can see down to the single pixel level.
|
| Can
TracTrix show a vector over a raster? |
|
Yes, this is a facility in
TracTrix and is a useful way to check that the vectors
represent the raster image.
|
| Can
TracTrix show dimensions in metrics and/or inches? |
|
Yes, either one, it's
users choice each time it's used.
|
| Can
TracTrix be set to jump a gap in a line? |
|
Incomplete or broken lines
can be edited, in the raster with our raster editing tools
or as vectors, into complete or single lines within
TracTrix or as vectors in your CAD software.
|
| How
many layers can TracTrix put vectors on? |
|
TracTrix can create and
place vectors on a near unlimited number of layers. This
is achieved by identifying in advance the different raster
line widths to be vectorized then each set of line widths
is placed on different layers after vectorization.
TracTrix also recognizes offset spot
colors. It will vectorize each different color and place
the resultant vectors from each color on different layers.
This too will provide an unlimited number of vector
layers.
|
| Can
I use TracTrix without a CAD package? |
|
TracTrix 2000 installs on
your CPU as a standalone conversion tool that does not
require a CAD package and as an object ARX application
that runs within AutoCAD. No separate license is required.
TracTrix Desktop 2 is a standalone package. Most users do
have a CAD package into which the resultant TracTrix
vectors are taken either before or after editing in
TracTrix. Some NC users take their cutting input files
directly from TracTrix.
|
| How
does TracTrix raster-to-vector conversion work? |
|
An algorithm in TracTrix
is designed to seek the pixels in the raster image and
'follow' them according to the parameters set by the
operator. These include following the edge line of pixels
in the 'Outline' following mode or following the
centerline of the selected line width of pixels in the 'Centerline'
following mode.
Additionally, TracTrix can be set
optionally to create vectors as lines, arcs, circles,
polylines, Beziers, NURBS or splines. The original image
and desired file type often dictate the mode selected.
|
| Definitions |
|
DXF
DXF is one of many vector file formats used for the
storage and exchange of CAD drawing data between different
CAD software applications.
Hybrid
file
A file containing both raster and vector information.
ISO
9000
ISO 9000 is an international certification of company
quality standards established by The International
Standards Organization (ISO), headquartered in Geneva
Switzerland. Certification may be required in order to do
business in certain industries, in certain countries, with
certain companies and many government agencies. There are
also other ISO standards with different numbers governing
different types of businesses and technologies.
Line
following
Line following software vectorizes interactively. The
operator watches as the software tracks along the lines in
an image and intervenes if an error is made. This is
slower than automatic vectorization but can produce better
results in certain types of complex images. Line Following
will be supported in a future release of TracTrix in
conjunction with other major technical advances.
Splines,
B-splines, NURBS and Bezier curves
A spline or B-spline curve is a blended piece
polynomial curve passing near a given set of control
points. The blending functions are the type that provide
more local control compared to other curves like a Bezier
curve. A Bezier is a polynomial curve passing near, but
not necessarily through, a set of given points.
A Bezier curve represents
an equation of an order one less than the number of points
being considered. A NURBS (Non uniform rational B-spline)
is a B-spline curve or surface defined by a series of
weighted control points and one or more knot vectors.
TWAIN
TWAIN is driver software which enables applications
software such as TracTrix and other graphics applications
to communicate with and drive your scanner. Once you've
set up an application to use TWAIN, its presence should be
almost invisible to you. Created by Hewlett-Packard, the
TWAIN standard is now widely used by other small format
scanner manufacturers
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