WinRHIZO, complete plant root measurement and analysis systems for agricultural and forestry research

For Root Morphology
And Architecture Measurement

IMAGE ACQUISITION COMPONENTS for Washed Root Measurement
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 an image acquisition device. WinRHIZO systems come standard with a desktop optical scanner as the image acquisition device. Optical scanners are well adapted to image acquisition of macroscopic objects like roots or leaves. We use standard commerical scanners (which you can use for many other applications) to which we add: a special lighting system (to avoid shadows, see insert below), accessories (to accelerate root positioning and scanning, 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 when used for artistic applications). It also gives tips specific to the scanner purchased. Our scanners are available in two different sizes of scanning area: 22 x 30 cm for Standard Area (STD) scanners 30 x 42 cm for Large Area (LA) scanners. Click here to see the specific scanner models and their accessories that we sell.
The picture is for illustration purpose only. It does not necessaraly illustrates the model sold.
Why use an optical scanner rather than a camera?
Scanners can produce images of many times the resolution of a camera (for a given price range).

A good 1600 dpi scanner (true optical resolution) produces images which have 1600 by 1600 pixels per inch (2.5cm).	Over a scan area of 8.5 by 11.7 inches, it produces an image of 13 600 by 18 720 pixels.

A good digital camera can produce images of 3000 by 2000 pixels.	Over an area of 8.5 by 11 inches, unlike the scanner it still produces an image of 3000 by 2000 pixels. It has an equivalent resolution of 256 by 235 dpi. The pixels are too big to measure very thin roots. Therefore, you must reduce the area and take more images. The above scanner image it is equivalent to 42 camera images!
It is easy to get good images using a scanner. Lighting is uniform over the entire scan area and it is not necessary to adjust the position, orientation or intensity of the light source. There are no focus or aperture rings to adjust. Calibration is permanent. Unlike a camera, the object-to-camera distance and zoom are always the same. They are reliable and last for a long time. RÉGENT INSTRUMENTS INC. imaging experts have experience in scientific image processing with scanners since 1988.
Regent's positioning system for scanners
Our positioning system significanlty increases your productivity for a very low cost. It is comprised of plastic blocks that can be installed and removed quickly to accommodate up to 18 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? 1. You don’t have to worry where to place the samples on the scanner glass. Once you have determined the sample positioning, you simply insert the samples in the open area on the glass for the acquisition of subsequent images. WinRHIZO has pre-defined positioning options for you to choose from. 2. Because WinRHIZO knows the size and position of the sample on the scanner glass, you can bypass the traditional Preview step. You save 10 to 20 seconds for each scan. That’s a lot of time after thousands of scans! 3. 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?
Even the best recognition algorithmn is worthless without a good image of the object to measure (Garbage-In, Garbage-Out). 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 is one example and is illustrated below.
Shadows are important because they have grey levels close to those of the roots. Deciding where to position the boundary between the root and its background is a difficult task when shadows are present.
When is a camera better adapted than a scanner?
A camera is better when extremely high magnification is required. By adding proper lenses or mounting it on a microscope, you can see more details than with a scanner BUT OVER A MUCH SMALLER AREA. Mychorizae and root hair are better analysed with such setups. A camera is also better when portability (like image acquisition in the field) is required. WinRHIZO can analyse images taken with a camera with a means of calibration.
Can Regent’s scanners be used in the field or at a remote location?
Desktop scanners cannot be used in the field but are easily transportable and usable in remote locations where electrical power is available.
An important point to consider when purchasing an image acquisition system is its TWAIN compatibility.
When an image acquisition device is TWAIN compatible, WinRHIZO (and many other programs) can obtain and analyse images directly from it. Otherwise, you must use another program to acquire and save images to the computer disk before loading and analysing them in WinRHIZO. Before selling a scanner, Regent’s tests its TWAIN compatibility with its products.
Why buy a scanner from Regent?
Although WinRHIZO can work with many scanner models that are TWAIN compatible, it is advantageous to purchase a scanner from Regent. The model you buy has passed our scientific quality control test. You get a scanner that is well adapted (fast, precise and reliable) for long term repetitive scientific measurements. Before deciding which scanners(s) to sell, we test many of the models available and we choose the best. You get a scanner that has a dual lighting system which produces shadow-free images when scanning roots. You get a scanner for which the TWAIN driver compatibility has been tested with our products. Unlike some other models on the market, our scanners support the Dual Scan system recommended for WinRHIZO. You are sure that our accessories will fit on the scanner. The root positioning system is specific to each scanner we sell. We calibrate our scanners against precise standards to obtain more accurate dimensional measurements. This calibration is supplied with the scanner and is automatically used by our programs. 6-You get competent and prompt technical support for image acquisition from people who not only sell the product but also use it. If problems arise, you don't have to contact two vendors, only one is responsible for finding the solution. You get our manual that illustrates how to scan biological samples for analysis with our programs (WinRHIZO, FOLIA...). This manual helps you to obtain the best images for accurate measurement and also gives some tips specific to the scanner that you have ordered. Some of our scanners come with a video on CD-ROM that shows how to install some of the scanner’s components and accessories. Note: Regent Instruments does not provide technical support for scanners or cameras it has not sold, nor do we guarantee their compatibility with our products. In case of incompatibility, you can scan the images with the scanner manufacturer's program, save them in tiff files, then open and analyse them in WinRHIZO.
Not all scanners are created equal.
The images below show the same roots scanned with two different scanners at the same resolution. As you can see, not only dpi (resolution) is important. The quality of optical, electronic and mechanical components has a great influence on what can be seen in an image (and hence, the precision of the measurements you make from it). Scanners are made for different applications, the graphics industry and home use being the major ones. Requirements for scientific usage are different. Eye-pleasing images are good, but it's better to accurately reproduce reality. Therefore, before selling scanners for scientific use, we test them carefully to make sure they have minimal qualities. You cannot rely on theoretical specifications alone.

From the images below, you can see that more detail is visible in a good quality scan at 800 dpi than in an average quality one at 1200 dpi. The 1200 dpi image will usually take more time to scan, consume more disk space and require more time to analyze but might not produce more precise measurements.
Target size is 5x5 mm

A scan at 1200 dpi on a 600x1200 dpi scanner.	A scan at 800 dpi on a 800x1600 dpi scanner.
WinRHIZO's optical scanner can be shared with other Regent's applications: WinDENDRO for annual tree ring analysis, WinFOLIA for leaf analysis, WinSEEDLE for seed and conifer needle analysis, WinSCANOPY for canopy analysis, It can also be used for other scientific or non-scientific applications like documents and photo scanning, desktop publishing, optical character recognition and teledetection.
To learn more about WinRHIZO click the following links or you can download our WinRHIZO brochure (1.3 MB). WinRHIZO WinRHIZO program for washed root analysis is available in three versions. Click to learn about the measurements that each version can perform. WinRHIZO program features. WinRHIZO design philosophy and the alternatives. WinRHIZO image acquisition components.
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