In design and engineering, JPG images are often avoided due to their many limitations. Like all raster images, they lose resolution when scaled, and they cannot hold the information required for CAD design. In the past, users would need to manually trace an image if they wanted their design in CAD format. Thankfully, this process has become incredibly easy with Scan2CAD’s quick and precise automatic conversion. After converting your JPG to DXF, you will be able to open your design in any CAD application. Check out our handy slideshow for a quick and easy way to learn all about JPG to DXF conversion.
Want even more detailed info? Read on for our complete guide to everything you need to know about JPG images and DXF files—plus, discover the complete Scan2CAD conversion process in a few easy steps.
Table of Contents
- What is a JPG file?
- What is a DXF file?
- Why convert from JPG to DXF?
- Example of JPG to DXF conversion
- Steps to avoid JPG to DXF conversion problems
- How to convert JPG to DXF
- How does the conversion work?
What is a JPG file?
JPG is the most common file extension type for files that conform to the JPEG compression standard.
JPG is an acronym for Joint Photographic Experts Group, with other file extension types for JPEG compression including JPE, JPEG, JIF and JFIF.
The JPEG compression method is known as a ‘lossy‘ type and is best applied to photographic images with smooth transitions between areas of color and tone. Using lossy compression means that the image will lose definition when edited. Because of this loss of definition, JPEG compression is not well-suited for line drawings, text, or solid graphics which have a sharp transition from black to white (for example, an ink drawing on paper).
When a black and white image is saved as a JPEG, it will be actually be saved as a grayscale image, and blocky artifacts will be introduced, blurring the definition between the ink and paper.
If you have a particularly ‘low quality’ file, converting from JPG to DXF can be problematic and the results may not be ideal. Luckily, we will address these problems in the section below, helping you create the perfect DXF file.
What is a DXF file?
DXF is a vector graphics format used in computer-aided design (CAD). It was created by Autodesk as a way of exchanging CAD files across different CAD programs. The acronym stands for Drawing Exchange Format.
Unlike the DWG file format, DXF is not a proprietary file type. This means that almost any CAD program on the market will be able to open a DXF file. As such, DXF is one of the most ubiquitous formats out there, which is why it’s Scan2CAD’s number one choice for vectorization.
Furthermore, the DXF file format is smaller than raster file formats. This is because it stores only the necessary information about vector elements in the image, rather than having to store color information for every pixel.
Why convert from JPG to DXF?
- For digitizing a hard copy of a drawing: you can scan an image into Scan2CAD and then convert it to a DXF to begin editing in a CAD application.
- To edit a drawing: you can’t edit specific elements of a raster image (JPG). You can only edit the image as a whole (e.g. by adding a filter) or draw on top of it. In contrast, vector file types like DXF are easy to edit. You can also use individual elements from a vector image and copy them for use in other drawings.
- For scaling an image: because raster images are made up of pixels, they become blurry and undefined when scaled upwards. Vectors, in comparison, are infinitely scalable. Check out our article on the differences between raster and vector images for more information.
- For sharing: the DXF format has many advantages compared to many other vector formats. Other formats, such as DWG, are proprietary formats, which means that they only open in a limited range of programs. DXF, meanwhile, is an open standard, which means that it is supported by practically all CAD programs on the market.
Example of JPG to DXF conversion
Let’s take a look at what happens when you convert your JPG without optimizing it first:
The magnified section above highlights the greyscale surrounding the JPG image. If we were to convert this JPG to DXF without modification, then the results would look like this:
The vectors above are displayed in red and magenta, whilst the raster is displayed in black. As you can see, the vectors are ‘noisy’ and undefined due to the pixelated nature of the raster image. Some of the vectors barely resemble the original lines which were meant to be converted. These are the types of issues that can occur when you vectorize an image without addressing any of the problems in your original raster image.
Luckily for you, we have some top tips to help you optimize your raster image before vectorization.
Steps to avoid JPG to DXF conversion problems
1. Use a better image format than JPG
The simplest way to avoid the above problems is to NOT use the JPG file type for line drawings, text or solid graphics. This file type makes use of lossy compression. As a result, it loses quality each time you edit it. Instead, for black and white images, we recommend using the TIFF file format (also known as TIF), set at Group3Fax, or preferably Group4Fax. TIFF uses lossless compression, which means that it will not cause the same issues as JPG, whilst still offering a relatively small file size.
Unfortunately, sometimes you will be sent a file in JPG format in the first place. If this happens, the damage will already have been done, and simply converting to TIFF won’t fix any issues. In this situation, there are some steps we can take to optimize the JPG file for better results.
2. Modify using thresholding
Thresholding is a way of setting all gray image parts (pixels) below a certain value to white, while setting all pixels above this value to black.
Scan2CAD contains 2 methods of thresholding—simple and adaptive. Simple thresholding applies the same threshold to the entire image, whilst adaptive thresholding allows you to set different thresholds for different parts of the image. In most cases, the simple method will suffice.
Thresholding couldn’t be simpler:
- With the JPG image loaded into Scan2CAD, select the menu option:
Raster Effects > Threshold > Simple
- You will be presented with a Scan2CAD dialog containing a preview window together with a threshold slider control.
- When you move the slider up and down, you will be able to see the resulting effects in the preview window.
- Zoom into the image to view it in greater detail, or zoom out to see the image as a whole.
- When the drawing elements of your image appear black and the background appears white, press the OK button to exit the dialog.
3. Clean up the image
Using JPG often degrades the quality of your image and introduces compression artifacts. However, even if you save your raster image in a lossless format (such as TIFF), you will still come across some common issues. Most raster images contain imperfections such as speckles, hairy lines and holes. These problems are particularly prevalent with scanned images, as shown in the image below.
These issues can be avoided with the use of Scan2CAD’s wide variety of cleaning tools:
- Thicken lines to help fix dithered or broken lines.
- Use Clean > Holes to fill in the gaps in lines containing ‘holes’, or Clean > Speckles to remove speckles from the image.
- OCR allows you to convert raster text to vector and arrange it into logical text strings.
- The Smooth tool helps remove the rough or ‘hairy’ edges that can appear around lines.
These are just a few of the many raster cleaning features that Scan2CAD provides as standard. You can make use of our Raster Quality Checklist to avoid or fix any of the above problems. You can also check out our top 10 raster effects to optimize your vector conversion.
How to convert JPG to DXF
- To convert from JPG to DXF, start by selecting the appropriate vectorization settings from the Type menu. In this case, we’re vectorizing a drawing from an architectural floor plan, and so we’ve chosen to use Architectural settings. For advice on which settings to use, check out our vectorization settings tips.
- Now, go to Run > Vectorization, click , or press F7.
The image above shows the new vector lines (in red) overlaid on the original vector lines (in black). As you can see, there are no errors with the vector lines.
- Once the image has been vectorized, it can finally be saved as a DXF file. It’s as simple as clicking File > Vector > Save As > DXF.
As you can see, the JPG to DXF conversion process is quick and simple. Interested in how the process works? Check out the section below.download your fully featured 14 day trial now
How does conversion work?
Raster-to-vector conversion works through image tracing. It is possible to trace the image manually, but it can be very time-consuming since it involves drawing over the image lines by hand. Instead, programs like Scan2CAD trace the image automatically.
Scan2CAD works by detecting lines, curves and text. Next, it draws over them with vector lines. The software can also make use of OCR (Optical Character Recognition) technology to detect and trace over text. Finally, the software saves the image as a vector file (e.g. DXF).
This process is much quicker than the manual tracing process. Of course, like most things, there are limitations to automatic tracing. However, by following our guidelines, it has the capability to save you hours of work and reduce your costs by hundreds of dollars in the long run.
Scan2CAD is the market leading vectorization software. It supports no less than 33 file types, and comes with a full editing suite. Interested? Check out Scan2CAD’s wide range of features, with our 14-day free trial.