Raster to Vector – What Types of Images Convert?
We often have customers who come to us with raster images that they want converting to vector, but the raster images are poor quality. This necessitates an extra step before the raster to vector process can begin – the images themselves need to be cleaned up. If this vital step is skipped, then the raster to vector conversion results will be less than perfect.
Many times even if images look okay when viewed in full-screen mode, when we zoom in and start really looking at the images, we can see that there are problems. Here is a list of the types of problems that often need to be fixed:
A skewed image occurs when a paper drawing has been fed through a scanner at an angle so that the lines are no longer perpendicular to the raster image.
A skewed image can cause significant deterioration during the vectorization process. Therefore, the image should either be re-scanned or re-drawn prior to the raster to vector conversion image quality in order to assure good results.
Dirty images are images with dots or smudges that have been transferred to the raster image. These dots and smudges may have occurred as a result of dirt on the scanner glass during the scanning process, or they may be inherent in the original drawing…coffee stains, erasure marks, slight tears, and wrinkles etc., which can be common in older paper drawings. If the imperfections do not interfere with the drawing itself it can be easily cleaned. However, solid black areas that obscure the drawing are more problematic and will require an expert in order to recreate the drawing in its original form.
If the lines on your image are dithered, you can see when they are magnified that they are made up of black speckles like the second and third lines to the left. If at all possible, you should rescan your drawing with more appropriate scanner settings. However, if this is not possible, then consult with raster to vector experts for a solution. Often professionals who regularly convert raster to vector have specialized tools that can mend the dithered lines.
Lines with holes
Sometimes when a drawing has been scanned at too high a resolution, the lines in the drawing may appear with holes. Scanning at a lower resolution should correct this problem, but often re-scanning is not an option. A good raster to vector converter, in the hands of an experienced r to v engineer, should be able to correct this problem with a minimum of fuss. Provided that the holes are not too large, this is just a matter of filling in the lines.
Automatic raster to vector converting software usually includes the technology called “gap jumping”. This means that when they vectorize a raster image they are able to “jump” over small breaks automatically.
This will not work if the lines on the image are very broken. Also, in using automatic raster to vector for GIS drawings, often the contour lines are too close together to form the gap jump technology, and it gets confused. In either of these cases, the only way to mend a very broken image or contour lines that are too close together is to draw new raster lines and arcs over the broken ones. Even rescanning does not always correct the problem. This requires an expert in order to handle this process efficiently otherwise it may take too long to improve the image quality to the point where it can be successfully vectorized.
The Goal is Good quality lines
Prior to converting your raster image to CAD, the goal is to have a raster image that has good quality lines, with little or no noise on the drawing. With a clean drawing and lines that are strong and distinct. It is possible to get good raster to vector conversion results, what we at CAD CAM Services, Inc. call CAD Perfect ™.
CAD Perfect ™ Images – Paying Attention to the Details
The technical data contained in your raster images are critical assets, and efficient management of this data is important for your business. Ensuring that you get only CAD Perfect ™ conversions guarantees that all of the little details have been tended to and that your converted CAD drawings are as good as, if not better than the originals!
CAD Perfect ™ raster to vector conversion makes archiving, retrieving, copying, editing, and sharing of your drawings easier.
CAD Perfect™ cad conversion work is a registered trademark of CAD / CAM Services, Inc.