| Step 1. Position your sample on the scanner |
| Disks are placed face down on the scanner for image acquisition. Most recent scanners sold by Regent have their glass at the same height as the plastic surrounding it, making large disk scanning more precise (the disk is in contact with the glass). Samples larger than the scan area can be analyzed by tiling two or more images (with the image editing software that comes with the scanner). |
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Disks are scanned face down.
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| You can scan the whole disk (this can take huge amount of memory) or you can scan narrow paths, a few millimeters or centimeters in width, from the pith to the bark. |
| For wood cores scanning, Regent's optional core holder and positioning system is offered. It eases and accelerates the scanning process by allowing the operator to rapidly position the samples at the same place on the scanner glass (thus eliminating the need to preview before a scan) and allows manipulation of cores during their preparation. This system can be rapidly added or removed at any time. |
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Wood cores in Regent's core holder (black handle) or glued on a piece of wood can be scanned and analyzed by WinDENDRO.
The positioning system fits on the scanner and has a slit to accept the holder for scanning the core. |
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| Step 2. Digitize samples |
To get an image of a sample, simply click the scanner icon in WinDENDRO main window. WinDENDRO controls the scanner directly. There is no need to use other software. WinDENDRO is TWAIN compatible, meaning it can get images from many different scanners models. A scan typically takes between 10 and 40 seconds to complete (depending on the image size), then the image appears on the screen. Regent only sell scanners with a rapid connection to minimize scanning time (click to learn more about scanners). WinDENDRO can also analyze TIFF image files produced by other scanning software programs (they must be in 256 gray levels or 24 bits color).
WinDENDRO can also analyze images from digital or video cameras (a calibration method is required).
To learn more about sample preparation required for scanning and WinDENDRO see our FAQs page. |
| Step 3. Ring detection |
| After image acuisition, the analysis is ready to be done. No anlysis is done until you indicate WinDENDRO where to measure rings in the image. This is done via the creation of paths. When the analysis is complete, paths are visible in the image and lines are drawn over the detected ring boundary. |
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Rings can be measured on disk radii (straight line) or on complex paths (made of two or more straight lines).
WinDENDRO has two automatic ring detection methods which can be overridden for manual operation. The first method is based on light intensity differences. It is simple, efficient and works fine for contrasted rings like those of conifers. The other tree ring detection method is called Teach & Show, and is a method where you show WinDENDRO tree rings in the image so that it will be able to automatically detect them . This method is more computer intensive and is well adapted for low contrasted rings like those of deciduous trees. There are limits however and minimal contrast is required in order to get a good level of automatic detection. When contrast is too low, you can work in manual mode. In this mode, you indicate interactively the position of each ring in the image. See our FAQ's page for comments about minimal ring width and contrast.
Ring width measurement is made perpendicular to the ring boundary. Tree-rings found by WinDENDRO are identified by lines drawn over the image along with the ring year and number. No modifications are made to the original image which is always available for future reference or analyses. The images can also be exported to other software programs (to create a report for example). They can also be saved with their analyses and later be retrieved and edited or validated by WinDENDRO. |
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Rings are identified by number and year and can be analyzed in any direction.
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| Step 4. Ring validation |
| For greater precision, the operator validates the analysis. In this regard we say WinDENDRO is a semiautomatic rather than an automatic system. This is done by browsing the image and looking for missing or false rings. Contrary to systems based on positioning tables, you can switch back and forth along the ring path without precision loss (due to backlash in the gears). Previously identified rings can be reviewed at any moment even years later. Adding or deleting rings is easily done interactively. When the mouse is held over a ring, the latter is highlighted (in yellow below). Clicking it deletes the ring, clicking at a place there is no ring adds one. Rings can be deleted in groups, moved or reoriented. |
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Pixel interpolation allows the operator to position rings between two pixels, increasing the effective resolution of the system.
WinDENDRO also has built-in some basic cross-dating features to facilitate ring validation. A ring width graphic is displayed and is updated as rings are added or deleted. A correlation coefficient between a sample and reference data is also calculated. |
| Step 5. Data saving and analysis |
WinDENDRO has its own (documented) format (tab delimited) that is well adapted for analysis in spreadsheet or other modern programs.
A utility program is included to convert WinDENDRO's data format to the decadal format used by dendrochronologists.
XLSTEM, a stem analysis program is offered as an option. It allows you to graphically visualize data produced by WinDENDRO and do standard stem analysis (like reconstituting tree growth as function of age, measuring tree volume...). XLSTEM is written as a macro that runs within Microsoft Excel.
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