Profilométrie 3D

(En anglais seulement) In order to facilitate eventual comparison between samples with similar surface, it is recommended to use a boundaries (surface positioning) template to standardize their positioning in the picture frame. This surface positioning template is a “.map” file containing a list of positions outlining the sub-surface’s boundaries and a reference image of the surface of interest.

The reference image should be considered as a representative (average) image of the different samples with a similar surface that will be used for the display of average mapping results taken from multiple comparable surfaces. In order to be representative (average) of all sample surface boundaries within the group of interest, template must be created using enough independent sample surface images. Of course, the number of independent images required will be a function of the extent of boundary variation within the group. Image processing software shall be used to create the representative (average) image.

The boundaries (surface positioning) template can be modified from time to time, in particular when data collection indicates that it is not representative of the population. For this reason, a version number is added to the template which is named using the following convention: “Template-X_SurfaceDescription_vV.map”, where X is the left (L) or right (R) side and V is the version number.

The following is the list of the left and right surface positioning templates currently available:
• Human: Distal Femur, Femoral Condyles, Tibial Plateau, Patella
• Sheep: Femoral Condyles, Tibial Plateau
• Rabbit: Femoral Condyles, Tibial Plateau
• Rat: Femoral Condyles, Tibial Plateau
• Mouse: Femoral Condyles, Tibial Plateau

NOTE. If the sample presents closed sub-surfaces (for example an entire tibial plateau with the medial and lateral plateaus), it is important to describe each of these regions of interest (sub-surfaces) in order to interpolate the mapping within the delimited boundaries.

1. Position the sample in the camera feed or place the camera towards a screen in order to visualize a representative (single or average) image of the sample in the camera feed. Ideally, sample’s surface should be at the center and occupies the maximum space in the image frame while remaining completely visible and allowing some clearance for eventual refraction compensation, if applicable.
2. Create the boundary of the sample surface in the camera feed. Note that it is important to edit/select a sub-surface in the Sub-SurfaceID field before adding a boundary in order to assign the boundary to a sub-surface.
2.1 Choose “Boundary” in “View” of the menu bar to see boundaries in the camera feed.
2.2 Edit the Sub-Surface ID field as defined in the associated protocol.
2.3 Choose “Add Boundary” in “Edit” of the menu bar and click in the camera feed to define the boundary along the sample sub-surface and a closed contour will be created.
2.4 If necessary, choose “Delete Boundary” in “Edit” of the menu bar and click in the camera feed at a boundary point along the sample sub-surface and the closed contour will be reshaped consequently.
2.5 Repeat steps 2.2 to 2.4 for each sub-surface of the sample.

3. Create a blank .map file and name it using the following convention: “Template-X_SurfaceDescription_vV.map”, where X is the left (L) or right (R) side and V is the version number.

(En anglais seulement) In order to dimension the sample and calibrate its image, two reference marks need to be created on the sample surface as far as possible from each other (ideally not over regions of interest). Marks should be made at approximately the same surface height (ideally at the average horizontal mapping plane, the focal plane of the camera), since it is the top-view image of the sample that is calibrated.NOTE. Different specified methods can be used to create those reference marks, but they should be made as small as possible (while being clearly visible on the sample and eventually on its image) and should remain mechanically stable and visible after immersion in saline solution (if applicable) and sample manipulation. For example, adding a small drop of India ink over a needle puncture of the cartilage layer at the boundary of the articular surface have proven to lead to good results. It might also be possible to use two distant, clear and unambiguous sample landmarks as reference marks.

1. If already created, open the blank “Filename.map” file to be converted into metric coordinates. Note that the corresponding image “Filename.jpg” should present two visible reference marks. If not already created and if the sample is still in the camera feed, add two reference indicators on the two visible reference marks.
1.1. Choose “Reference 1 (red)” in “Edit” of the menu bar and click in the camera feed at the first reference mark.
1.2. Choose “Reference 2 (blue)” in “Edit” of the menu bar and click in the camera feed at the second reference mark.

2. Set the metric values of the reference marks.
2.1. Choose “Calibration” in “Edit” of the menu bar.
2.2. Report the X and Y metric coordinates of the reference 1 and reference 2 in the “Calibration” pop-up window according to a specific method, currently available is the “Mach-1” method.

“Mach-1” method: This method allows converting the pixels coordinates of the positions into metric coordinates that will be used for a mechanically-controlled surface mapping with the 2 horizontal stages of a multi-axial Mach-1 mechanical tester. The coordinate system used in this method corresponds to the Mach-1 horizontal stages where it is preferable to set X and Y origin at the first reference mark. With the sample/testing chamber mounted onto the Mach-1, move the stages in such a way that the center of the Mach-1’s indenter (its vertical axis) is positioned just over the first reference mark (red indicator), set the position of the X and Y stage to zero position. Repeat the same procedure for the second reference mark (blue indicator), report the X and Y stage position in the “Calibration” pop-up window. Note that since it is possible to increase the effective scanning area (limited by the stages) of the Mach-1 by manually rotating/repositioning the sample or sample/chamber assembly, a configuration index “i” is added to this characterization (by default i=1). Note that it is recommended to keep this configuration index (i) in all Mach-1 raw data generated under configuration (i).

3. Create a “Filename-Dimensioning.map” file, where “Filename” can be defined in an associated protocol.
3.1. Verify that reference 1 and reference 2 indicators are displayed in the camera feed and that their metric coordinates (according to the chosen method) has been reported in the “Calibration” pop-up window.
3.2. Choose “Create .map” in “File” of the menu bar and all positions, boundaries and references displayed in the camera feed will be saved in the .map file and a snapshot image “.jpg” of the camera feed will be saved in the same folder. Also, two characterizations “ScanX(mm)” and “ScanY(mm)” containing the metric coordinates of the two reference marks and those of each position of the grid will be saved.

(En anglais seulement) NOTE. If no testing chamber is used proceed to step 5.

1. Completely screw the sample holder into the testing chamber and place the sample over it. If applicable, center the sample relative to the holder and rotate it in such a way that its orientation will approximately correspond to that of the corresponding surface positioning template image when seen by the technician in front of the testing chamber. Using a black marker, draw a mark on the top of the sample holder that will be used for the repositioning of the sample over the holder.

2. Remove the sample and unscrew the sample holder.

3. Depending on the sample type, a sample has to be attached to the sample holder following an appropriate method, either with screws and/or cyanoacrylate glue (recommended: Loctite 4013).

“Screws” method: In the case of sample holder (a – see Figure 1a), place the flat sample side in firm contact with the sample holder. Secure it with at least 2 screws from the bottom side. Make sure that the screws remain at least 1 cm away from the surface. In the case of sample holder (b – see Figure 1b), place the flat sample side in firm contact with the sample holder. Secure it from the periphery using its 6cone-ended screws. In the case of sample holder (c – see Figure 1c), place the sample in the middle. Secure it with its 2 screws.

“Glue” method: In the case of any sample holder with a flat portion (see Figure 1), make sure that the bottom surface of the sample and the flat portion of the sample holder are dry to ensure a good adherence. In the case of articular surfaces, apply the glue on the sample bottom (the bony part) and be careful not to touch the cartilage surface. If by mistake the glue touches the sample, try to clean the surface by using a flux of PBS, and report approximately the touched area in the laboratory book. The glued sample should be maintained for at least 1 minute to ensure a good adherence.

4. Screw the assembly into the testing chamber.

5. If required, create two reference points on the surface as per the “Calibration of the sample” section. If required, measure the horizontal distance between the references with a calibrated caliper and report the value (ideally, at a location specified in an associated protocol).

6. Adjust the position of the camera and its focus in such a way that the sample’s surface occupies the maximum space in the live camera feed while remaining completely visible by keeping a margin of about 5% at the 4 sides (right, left, up and down) to accommodate an eventual water refraction compensation, if applicable. It is recommended to use an appropriate surface positioning template to facilitate eventual mapping comparison between samples.
6.1. Choose “Import .map” in “File” of the menu bar.
6.2. Select the corresponding surface positioning template (*.map) and boundaries will be displayed by a closed contour (solid line) in the camera feed.
6.3. Adjust the position of the camera and its focus in such a way that the sample’s surface boundaries fit those of the surface positioning template.

7. Superimpose a position grid to the sample image. Positions could be added one by one according to a snapping grid (aligned) or anywhere on the sample. Also, positions could be imported through a previously created .map file. Note that it is important to edit/select a sub-surface in the Sub-SurfaceID field before adding a position in order to assign the position to a sub-surface.
7.1 If applicable, choose “Import .map” in “File” of the menu bar and select the corresponding position grid and the positions will be displayed by a circled marker in the camera feed.
7.2 If applicable, choose “Grid” in “View” of the menu bar to display a grid of snapping dots in the camera feed.
7.3 Edit the Sub-Surface ID field as defined in the associated protocol.
7.4 Choose “Add Positions” in “Edit” of the menu bar and click in the camera feed to add positions at each location of interest on the sample sub-surface.
7.5 If necessary, choose “Delete Positions” in “Edit” of the menu bar and click in the camera feed at each position that is not overlaid on a location of interest on the sample sub-surface and the position will be deleted from the camera feed.
7.6 Repeat steps 7.3 to 7.5 for each sub-surface of the sample.

8. If required, create the specific boundary of the sample sub-surfaces in order to refine the outline of the mapping surface for this specific sample (using at least 30 boundary points). If needed, surface boundary layer from the positioning template can be deleted first. Note that this step is important for the interpolation of characterization values to the boundary to obtain a complete mapping of the sample surface. Note that it is important to edit/select a sub-surface in the Sub-SurfaceID field before adding a boundary in order to assign the boundary to a sub-surface.
8.1. Choose “Boundary” in “View” of the menu bar to see boundaries in the camera feed.
8.2. Edit the Sub-Surface ID field as defined in the associated protocol.
8.3. Choose “Add Boundary” in “Edit” of the menu bar and click in the camera feed to define the boundary along the sample sub-surface and a closed contour will be created.
8.4. If necessary, choose “Delete Boundary” in “Edit” of the menu bar and click in the camera feed at a boundary point along the sample sub-surface and the closed contour will be reshaped consequently.
8.5. Repeat steps 8.2 to 8.4 for each sub-surface of the sample.

9. If required, add reference indicators on the two reference marks previously created at step 5.
9.1. Choose “Reference 1 (red)” in “Edit” of the menu bar and click in the camera feed at the first reference mark.
9.2. Choose “Reference 2 (blue) in “Edit” of the menu bar and click in the camera feed at the second reference mark.

10. Create this blank “Filename.map” file, where “Filename” is standardized filename format that it is recommended to define in an associated protocol (refer to Appendix I for a recommended file naming convention). When filename standardization is not necessary, any name can be used as “Filename”. Choose “Create .map” in “File” of the menu bar and all positions, boundaries and references displayed in the camera feed will be saved in the .map file and a snapshot image “.jpg” of the camera feed will be saved in the same folder.

Note. It is important to edit/select a sub-surface in the Sub-SurfaceID field in order to assign a boundary to a sub-surface.

Click the camera feed panel on the first reference mark and a red marker will appear. At each click, the red marker will relocate.

(En anglais seulement) Note. It is important to edit/select a sub-surface in the Sub-SurfaceID field in order to assign a position to a sub-surface.

This function allows the user to define a position of interest on the sample. Click the camera feed panel at each location of interest and a position marker will be added. When a snapping grid is displayed in the camera feed (grey dots), click and hold down the left mouse button in the camera feed panel and position markers will be added and be aligned to the snapping grid until the user releases the left mouse button.

Future measurements will be taken in the same order that position markers are added to the camera feed panel.

(En anglais seulement) The “.map” file is a tab-delimited text file containing the results of various characterizations performed on a single sample surface. Each column of the file describes information and results for one particular type of characterization (referred to as “CharacterizationX(Units)”) with the format presented in the table.

Note that in order to be properly managed by the Mapping Toolbox software, all raw data and “.map” file describing characterizations of a single sample surface should be placed in a single folder named “Filename” (see naming convention below). Any name can be given to a “.map” file, but it is recommended to use the following convention:
- a “.map” file containing only “PixelX”, “PixelY”, “PointID”, “PointType” and “Sub-SurfaceID” is named “Filename.map”.
- a “.map” file also containing results from CharacterizationX(Units) is named “Filename-CharacterizationX.map”
- a “.map” file containing results from Characterization1(Units), Characterization2(Units) and … is named “Filename-Characterization1-Characterization2-….map”. Whenever possible, in order to reduce the filename length, the category of the characterization can be used to describe characterizations of the same category. For example, a “.map” file containing the characterizations ScanX(mm) and ScanY(mm) could be named “Filename-Indentation-Dimensions.map”.

(En anglais seulement)

The camera feed window of the software displays:
a. Actions accessible in “File” of the menu bar: