What Edge Detection Parameters (EDP) Should I Use?

By: Kevin Rivard

Question: What Edge Detection Parameters (EDP) should I use?

Answer: When using WipFrag to analyze muck piles, you can use the following guidelines:

Fines = Sliders to the right

Medium = Sliders in the middle

Large = Sliders to the left

Generally you want to have accurate nets on the small- to medium-sized particles. Once you find a suitable net for this size of material you can manually edit the larger material. Using this method will help provide more accurate results. 

It’s also recommended that you try to keep a similar EDP for images of the same muck pile, or when trying to compare different muck piles.

If finer adjustments are required, you can activate the ‘Show Advanced Controls’ checkbox to access numeric inputs featuring a wider range of finer adjustments than the basic sliders provide.

In Delta, an advanced version of WipFrag software that runs on WipWare automated photoanalysis systems, we use a process called Best Fit EDP. For online systems, this process is usually done on-site at the time of installation. It is implemented by taking an image of typical material once all hardware and software settings have been completed. We manually trace as many particles as possible and then run the Best Fit EDP feature. The software will then try and match the manual trace of the particles using the available EDP settings. Best Fit EDP outputs a set of numeric values which will be entered into the EDP advanced controls. This method is very accurate and provides our online systems with well suited Edge Detection Parameters. It is rare that an online system EDP will need to be changed, but if so can be done remotely from our headquarters.

Best Fit EDP was recently added to WipFrag software. Because of the time involved in editing an image to produce a good Best Fit EDP, this feature is most practical in order to reduce the amount of manual editing required if you are going to be analyzing a large number of images (20, 30 or more) of the same material under the same conditions. For the majority of users, where smaller batches tend to be analyzed at once, using the sliders to adjust the EDP is faster.

Within WipFrag, there is also a feature called Auto EDP which attempts to determine the edge detection parameters automatically. This feature works well as long as the particle size range is narrow.