A Complete 2D Photo Digitizing System
The 2D Template Digitizing page shows how to set up and digitize templates and patterns with a camera. There are other details to consider to put a whole system together. The components of a complete photo-digitizing system:
- An area to place templates and patterns
- A camera
- PhotoModeler software
- External CAD/CAM software
- Optionally, mounting and control equipment for permanent camera setups
We will discuss the details of what is needed for each of the above.
An area to place templates and patterns
You will need a flat area where your templates and patterns can be laid out, where the targets can be placed (sometimes permanently placed), and where there is sufficient room for the photography. The Field of View Calculator might help with determining the space you need if you have a camera in mind. In addition, there will need to be sufficient light to get good quality photos, and appropriate light direction for some templates and patterns (see the mounted section below).
Choosing a camera can be one of the harder decisions. Sometimes you will already have a camera and will be using that, but it is good to know what are the criteria for a good camera for photo-digitizing. Criteria for a photo-digitizing camera:
- good resolution, and high-quality images
- non-zoom, prime lens preferably
- access to a lens that will capture the template size needed
- can it be tethered, if it is to be used in a mounted setup
- within budget
There are many cameras that meet these criteria. To get a non-zoom lens you will often have to spend a bit more and use a DSLR or a mirror-less camera. Then you can purchase the lens of your choice. You will typically get a lens on the wider side (small focal length number). Lenses between 18mm to 30mm (in 35mm equivalent size) are suited to these tasks. Interestingly, cameras in mobile phones meet a lot of these criteria. Their resolution can be lower and they can’t be easily mounted so they aren’t always suitable, but some mobile phones are an inexpensive way to start experimenting.
Note that while a prime, non-zoom lens is preferred, if you have access to a camera with a built-in zoom, where the zoom can be made consistent (such as when camera powers up it always goes to the most wide-angle setting), and otherwise meets the other criteria, you can certainly start with the camera and you may find it does a sufficient job.
A camera example
Although many cameras can be used, we will provide an example of a camera and lens combination that will work in many photo-digitizing setups. You don’t need to use this camera – it is solely an example of how we match the criteria. One example camera:
- Camera: Nikon DSLR D750
- Lens: Nikon 24mm
How and why were these chosen? The D750 was chosen because it; a) is a DSLR (different lenses can be used), b) has good resolution (24MP), c) has a full-frame sensor (so a larger area can be captured for a given lens length), e) is good quality at reasonable cost, and f) can be mounted and tethered if needed. The 24mm lens was chosen because it is a non-zoom, it is a reasonable cost, and it is wide enough to give good coverage, but not so wide that its distortions are hard to compensate for.
A very useful thing to know about your camera and lens combination is how big a pattern can it capture. This is defined by the camera specs and the distance you can place the camera from the pattern. So the size of your room will be key here. The Field of View Calculator will help you determine the largest pattern you can capture in one photo (note there are techniques for capturing larger patterns with multiple photos).
There are many good camera retailers but a well-known one is B&H Photo. You can search the site to find ‘Nikon D750 body only’, and you can search all wide-angle Nikon prime lenses on their lens search page.
Coded Targets are needed to perform the initial setup (which, in part, calibrates your camera), and then to help with plane definition and the camera position needed during the pattern digitization. These Coded Targets can be printed on plain paper with your own laser printer right from within PhotoModeler, and then affixed to the work surface with tape or something similar.
In some scenarios, you may want to make a few of the targets permanent in your digitizing area. This would involve firmly taping down of the targets or covering them with a matte cover. Anything placed on top of the targets must not be reflective or shiny (for example typical packing tape will not work if it is on top of the coded target rings).
PhotoModeler Standard with Template Pattern Capture Addon package (or as a subscription) is needed to perform the accurate setup and digitization steps. Digitization can be done within PhotoModeler or orthographic-mapped images can be exported for external tracing.
External CAD/CAM software
In most cases, you will need other software to finalize your designs and drive your CNC machine. PhotoModeler has a nice interface with Rhino 3D for the CAD aspect, but other software will work as well. If the software can handle 2D DXF files of outlines (or background images for tracing) that should be sufficient.
Mounting and control equipment for permanent camera setups
If you will be permanently mounting the camera on a wall or a ceiling (used in high-throughput and production environments) you will need:
- mounting hardware
- remote power
- remote control
- remote image download
- suitable lighting
Most modern mirrorless and DSLR will allow remote control and remote image access of some form. The remote control and image access can sometimes be done wirelessly, but a wired connection might be more stable.
The mounting hardware can tie into the camera’s standard screw socket and be a clamp or various arms. You will want the setup to be stable and secure. The B&H Photo online shop has various hardware for mounting, as does Tether Tools (see below).
For wired remote power and control, Tether Tools has some excellent options. Using our Nikon D750 example above, we can see the wire and software needed to remotely control and download images here: Tether Tools D750 page. And to remotely power the camera there is the Nikon power coupler. Tether Tools has solutions for many different cameras. You can check to see if your camera is on the list.
Lastly, you will want to ensure your digitizing area has sufficient lighting. If you regularly digitize shiny material (such as Mylar sheets) lighting to the side, instead of from above, may work better as it will produce less glare.
What is the best way to get started and to learn the system if you are new to photo-digitizing and PhotoModeler? We recommend you try the evaluation software and use any camera you have access to (like a mobile phone) to get a feeling for the system. This way you won’t need to spend any money to start your first test. Start with a simple small template, and follow this video. Once you’ve seen the system work you can contemplate different/better cameras, and think about how it will fit into your workflow.
There are a number of components needed to create a full photo-digitizing system for 2D templates and patterns. This article outlined those components with some examples and possible sources. If you have any additional questions please don’t hesitate to ask firstname.lastname@example.org.