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Finding the Area Inside a Tennis Racquet Frame
I was working with the software mentioned below and decided to post this. A TT member may want to find the area of some racquet head, old or maybe even new. So here it is if it's ever of any use.
First, I'm not using a photo of the racquet because of more error because of the the camera position. Also, when imported, the size of the image will likely not be correct and would have to be exactly scaled beforehand in a photo editor. I'm not going into the details how to measure in the software and scale to correct.
Note: I posted something like this is the past in some thread, but I didn't give specfic details. Also, then I used a more tedious method where I converted a file into a .dxf file for CAD and did the work there after a number of necessary modifications.
This requires the following:
2 sheets of paper--colored is better unless you color (define) the edges before scanning (string bed is too large and the scanner bed most likely isn't large enough to do with one piece)
Pencil or pen, etc.
Scissors
Computer
Free: Inkscape open-source vector graphics software
Scanner
Note: These are the basics. I'm not getting into extra details about paths and nodes or other aspects of the software. It's minimal steps for most situations. It's quicker and easier than the text seems to present it.
1. Trace the shape inside the frame on the sheets of paper. Cut them out (a top section and bottom section). Lay them on top of the strings if strung to be sure the whole area is covered with no overlap.
2. Draw a square on each paper section, such as 2" x 2" or 3" x 3". This will let you check a known area in the software later as confirmation.
3. Scan each section with your standard scanning software. A common JPEG works. 300dpi is a good enough resolution to work with when defining the borders in the software.
4. In Inkscape (installed like common software): File>Import. Locate and choose a section that was scanned. Pop-up image import: Select the following: Embed, From file, and any rendering mode. OK.
5. The image appears on the workspace. File>Document Properties. Then make display units in inches. Close the Document Properties window.
6. Use scroll bars and zoom to display the square so it is large enough to work with. On the left in the toolbox, click the "Draw Bezier Curves and Staightlines." It resembles a blue tipped pen. It is above the yellow "pencil."
7. With the "Draw" tool just selected you'll see "Mode" at the top-left. Click on the first "Create regular Bezier path" or "Create a sequence of straight lines." Both will work for this.
8. Click a corner of the square to set a node. Go around clicking each corner. When you return to the first node set, it will turn red with the pointer on it. Click again. There is now a path around the square you drew (dotted line shown). The square is still selected.
Optional: You can select and see the nodes of the path around of the square by selecting the "Edit paths by nodes" tool (triangle with with three dots) at the left in the toolbox.
9. Now to find the area.
The square should still be selected. On the menu bar, click "Extensions." Then click Visualize Path>Measure Path. In the window that appears, change the measurement type to "Area." The font size and other options below determine how and where the area text appears relative to the square. Make the text larger to make it more visible. Set the length unit to inches. Click Apply. The software will perform the calculation. If it gives an error, make sure the path of the square is selected as noted above. Click on the work area or close the Measure window. You should see the area of the square displayed, such as 9 sq. in. for the 3" square (image size will provide acccurate results with imported image). There is likely to be a discrepancy, such as 9.03 or something, even if you drew the square well in the first place. That's just a matter of the manual precision.
Now, just repeat the process. This time, after selecting the "Draw Bezier Curves and Staightlines" tool, carefully click around on the outside of the racquet section, completing it as accurately as possible. Zoom in and use the scrolls bars to work your way around. You're performing the same process but instead of four lines, it's more clicks to create more nodes for the path around the racquet section. Use the area function noted above when the path is completed. Then do the same thing for the other racquet section. Add the sections together for the total.

Finding the Area Inside a Tennis Racquet Frame
I was working with the software mentioned below and decided to post this. A TT member may want to find the area of some racquet head, old or maybe even new. So here it is if it's ever of any use.
First, I'm not using a photo of the racquet because of more error because of the the camera position. Also, when imported, the size of the image will likely not be correct and would have to be exactly scaled beforehand in a photo editor. I'm not going into the details how to measure in the software and scale to correct.
Note: I posted something like this is the past in some thread, but I didn't give specfic details. Also, then I used a more tedious method where I converted a file into a .dxf file for CAD and did the work there after a number of necessary modifications.
This requires the following:
2 sheets of paper--colored is better unless you color (define) the edges before scanning (string bed is too large and the scanner bed most likely isn't large enough to do with one piece)
Pencil or pen, etc.
Scissors
Computer
Free: Inkscape open-source vector graphics software
Scanner
Note: These are the basics. I'm not getting into extra details about paths and nodes or other aspects of the software. It's minimal steps for most situations. It's quicker and easier than the text seems to present it.
1. Trace the shape inside the frame on the sheets of paper. Cut them out (a top section and bottom section). Lay them on top of the strings if strung to be sure the whole area is covered with no overlap.
2. Draw a square on each paper section, such as 2" x 2" or 3" x 3". This will let you check a known area in the software later as confirmation.
3. Scan each section with your standard scanning software. A common JPEG works. 300dpi is a good enough resolution to work with when defining the borders in the software.
4. In Inkscape (installed like common software): File>Import. Locate and choose a section that was scanned. Pop-up image import: Select the following: Embed, From file, and any rendering mode. OK.
5. The image appears on the workspace. File>Document Properties. Then make display units in inches. Close the Document Properties window.
6. Use scroll bars and zoom to display the square so it is large enough to work with. On the left in the toolbox, click the "Draw Bezier Curves and Staightlines." It resembles a blue tipped pen. It is above the yellow "pencil."
7. With the "Draw" tool just selected you'll see "Mode" at the top-left. Click on the first "Create regular Bezier path" or "Create a sequence of straight lines." Both will work for this.
8. Click a corner of the square to set a node. Go around clicking each corner. When you return to the first node set, it will turn red with the pointer on it. Click again. There is now a path around the square you drew (dotted line shown). The square is still selected.
Optional: You can select and see the nodes of the path around of the square by selecting the "Edit paths by nodes" tool (triangle with with three dots) at the left in the toolbox.
9. Now to find the area.
The square should still be selected. On the menu bar, click "Extensions." Then click Visualize Path>Measure Path. In the window that appears, change the measurement type to "Area." The font size and other options below determine how and where the area text appears relative to the square. Make the text larger to make it more visible. Set the length unit to inches. Click Apply. The software will perform the calculation. If it gives an error, make sure the path of the square is selected as noted above. Click on the work area or close the Measure window. You should see the area of the square displayed, such as 9 sq. in. for the 3" square (image size will provide acccurate results with imported image). There is likely to be a discrepancy, such as 9.03 or something, even if you drew the square well in the first place. That's just a matter of the manual precision.
Now, just repeat the process. This time, after selecting the "Draw Bezier Curves and Staightlines" tool, carefully click around on the outside of the racquet section, completing it as accurately as possible. Zoom in and use the scrolls bars to work your way around. You're performing the same process but instead of four lines, it's more clicks to create more nodes for the path around the racquet section. Use the area function noted above when the path is completed. Then do the same thing for the other racquet section. Add the sections together for the total.
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