WinRHIZO is a complete plant root measurement and analysis systems for agricultural and forestry research.
Image Analysis for Plant Science
Regent Instruments Inc. since 1991




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Image Acquisition

With one mouse click you can digitize and analyse roots !

Simply place the roots directly on the scanner glass or in Regent’s water-proof trays. Root positioning is easy and fast with Regent’s positioning system for optical scanners (see below). Roots can overlap and do not need to be randomly distributed.


Click the scanner icon to digitize the roots and wait a few seconds for the scan to complete and the image to appear on screen. There is no need to use another program to digitize the images, WinRHIZO controls the scanner (or a digital camera) directly. It is TWAIN compatible, meaning that it can get images from many scanners or cameras. It can also analyse images stored in tiff or jpeg files.


A few seconds later, the analysis is complete and roots found by WinRHIZO are identified by colored lines in the image. The colors used for drawing them are coded according to the root diameter. Some analyses (Nodules counting, Color and Topology for example) require interactions from the operator before proceeding.

Root length and diameter are measured with Regent’s unique method** and with Tennant’s statistical method. With the former, measurements are made continuously at each point along the root. Root overlap at forks and tips are taken into account to provide accurate measurements of length and area. Some measurements made by the system can be overridden by the operator.


The last step of the analysis is data saving. WinRHIZO knows when data are ready to be saved and does this automatically. Data files are in ASCII (text) format easily readable by many programs including spreadsheet style like Excel. Images and their analyses can also be saved to files for later validations, reanalyzes or for visualization in other software programs.


Roots can be measured automatically by WinRHIZO when they are extracted from the soil and washed of debris and soil particles. Before analysis, the roots must first be digitized with a scanner or camera.

WinRHIZO standard systems uses a desktop optical scanner as the image acquisition device. Optical scanners are well adapted to image acquisition of macroscopic objects like roots or leaves. Regent’s scanners come with:

  • Accessories to accelerate root positioning and scanning,
  • A special lighting system to avoid shadows (see below),
  • A permanent calibration to increase the measurement precision,
  • And a manual that explains how to scan biological samples (root, leaves, seeds...) for analysis with our programs (scanning for scientific analysis is different than for artistic applications). It also gives tips specific to the scanner purchased (such as scanning speed vs. quality issues) .

Regent’s scanners can be used for other applications (document or photo scanning). They are available in two different sizes of scan area:

  • 22 x 30 cm for Standard Area (STD) scanners,
  • 30 x 42 cm for Large Area (LA) scanners.

You can find the specifications of our most recent models by clicking here

Our positioning systems significantly increase your productivity for a very low cost. It is comprised of plastic blocks that can be installed and removed quickly to accommodate up to 12 or 24 different scan area sizes (depending on the scanner model). Together they form a semi-opaque area with a hole (the scanned area) for sample placement. Trays that match these rectangular scan areas are supplied with a complete system. They can also be purchased at any time. These trays allow you to scan immersed roots, which are easier to spread than dry roots.


How does it increases the productivity?

  • You don’t have to worry where to place the samples on the scanner glass. Once you have determined the sample positioning scheme, you simply insert the samples in the open area on the glass for the acquisition of subsequent images. The WinRHIZO program has pre-defined positioning options for you to choose from.
  • Because WinRHIZO knows the size and position of the sample on the scanner glass, you can bypass the traditional scanner Preview step. You save 10 to 20 seconds for each scan. That’s a lot of time after thousands of scans!
  • While a sample is being scanned or analysed, you (or a second operator) can prepare the next root sample in another tray away from the scanner.

Why an additional lighting system?

Without a good image of the object to measure, an unnecessary complex and lengthy root detection algorithm is required. Root image acquisition with an optical scanner without proper attention to the lighting system, might produce artifacts that make root identification tedious and imprecise. Shadow (below) is one example.

Shadows have grey levels close to those of the roots. Determining the position of the root boundary is much more difficult when they are present.

* “WinRHIZO™, a root-measuring system with a unique overlap correction method”, Arsenault, J.-L., S. Pouleur, C. Messier, and R. Guay. 1995. HortScience 30: 906. (Abstract).
** “Accuracy of Measurements with Mac/WinRHIZO™”. Stephan Pouleur, REGENT INSTRUMENTS Technical note #3, 1995, pp. 1-4.
*** “A test of a modified line intersect method for estimating root length”. Tennant D. 1975, J. Ecol. 63. pp. 995-1001.