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--- nxt_ar_toolkit [2016/08/02 19:39] – [Optional: Step 4: Debugging Marker Recognition] dwallace
+++ nxt_ar_toolkit [2017/07/17 03:13] (current) – [Step 8: Using Multiple Markers for Localization and Navigation] dwallace
@@ Line 3: / Line 3: @@
 **Author:** Dylan Wallace Email: <[email protected]>
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-**Date:** Last modified on 08/02/16
+**Date:** Last modified on 08/28/16
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 **Keywords:** ARToolkit, Computer Vision, Software, SDK, Path Planning
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-{{ :sampleimageforwritingtutorial.jpg?200 |}}
+{{ :dylanw:img_0980.jpg?500 }}
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-The photo above depicts <fill in the blank> which allows you to <fill in the blank>. The big picture problem is tracking movement for computer vision and navigation applications. Solving this partially or completely is important because it allows for objects to be quickly located, and used in programs for various applications. This tutorial shows you how to install, setup, and use the ARToolkit, and takes approximately 3 hours to complete.
+The photo above depicts coordinate tracking of a marker with the ARToolkit SDK, which allows you to track the relative position of something with a marker attached to it. The big picture problem is tracking movement for computer vision and navigation applications. Solving this partially or completely is important because it allows for objects to be quickly located, and used in programs for various applications. This tutorial shows you how to install, setup, and use the ARToolkit, and takes approximately 3 hours to complete.
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 ===== Motivation and Audience =====
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   * Know how to use basic Linux and Windows commands
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-  * Perhaps also know how to program in C/C++
+  * Perhaps also know how to program in C/Cpp, especially with Visual Studio.
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-  * Perhaps additional background needed may include experience with other applications such as OpenCV.
+  * Perhaps additional background needed may include experience with other frameworks such as OpenCV or OpenGL.
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   * This tutorial may also attract readers who are interested in path planning, computer vision, NXT applications, or augmented reality.
@@ Line 44: / Line 44: @@
 ==== Step 3: Obtain Missing DLLs ====
-If you are running on a newer Windows installation, it is possible that you do not have the Visual C++ Redistributables required to run the ARToolkit SDK. I recommend downloading them [[https://www.microsoft.com/en-us/download/confirmation.aspx?id=40784|here]] before trying to run any ARToolkit examples.
+If you are running on a newer Windows installation, it is possible that you do not have the Visual Cpp Redistributables required to run the ARToolkit SDK. I recommend downloading them [[https://www.microsoft.com/en-us/download/confirmation.aspx?id=40784|here]] before trying to run any ARToolkit examples.
 ===== Using the ARToolkit =====
@@ Line 94: / Line 94: @@
 **Orange/Yellow Outline:** This means that the maximum pose error was exceeded (yellow is for multi-marker). This means that the position error between the estimated image and the actual image is too great to get the transformation for the marker. This could most often be fixed by recalibrating your camera, improving lighting conditions, or getting a higher resolution camera.
+==== Step 5: Creating a New Project ====
+Once you have the example program simpleLite working well with marker recognition and tracking, you can move onto creating your own project. For developing your own projects using the ARToolkit, I recommend using Visual Studio 2013 or higher. Visual Studio has great support for the ARToolkit SDK, and all of their example projects have been provided as Visual Studio projects to modify or use as reference.
+**Note:** With recent updates to ARToolkit, it can be very difficult to create a new project in Visual Studio for ARToolkit. If you run into these issues, I recommend doing your development within and already-existing project within the provided ARToolkit5 Solution. This will make the process much easier to debug, and take away the worries of creating and maintaining your own project.
+To begin with creating a new project, simply open up Visual Studio and create an empty Visual Cpp project. Once you have created the empty project, you will need to add a .c file to the project. I named my file coordinate_tracking.c, because that was the use that I needed out of the ARToolkit. However, the ARToolkit is wide in its ability and uses.
+Once you have created the project, you will need to add the include and library directories to your project. Do this by right-clicking the project, and going to Properties. Under properties, look for the VCpp Directories tab. First click on the drop-down for include directories, and in the pop-up window, add a new directory. The directory that you will need to add here is the include folder contained in the ARToolkit5 directory. Next, do the same thing for the library directories, except this time, add the lib folder of the ARToolkit5 directory. Now, go to the Input tab under the Linker tab, and select the additional dependencies drop-down. Here you will need to ARd.lib, ARvideod.lib, glut32.lib, and ARgsub_litd.lib.
+Finally, you need to copy over some data from the ARToolkit5 bin folder. First, copy the Data folder over to your project folder. Next, copy DSVL.dll, DSVLd.dll, ARvideo.dll, and ARvideod.dll over into a new folder called Debug within your project folder.
+Once you have all of this configured, you are ready to create your first program with the ARToolkit SDK.
+==== Step 6: Modifying the Simple Program to Track Coordinates ====
+Now that you have successfully setup, tested, and even created a new project with the ARToolkit SDK, you are finally ready to create custom code with the ARToolkit SDK. However, instead of creating all of the code from scratch, it is good to build off of the simpleTest.c program, provided with the ARToolkit SDK.
+For reference on how the simpleTest.c program works wth the ARToolkit SDK, refer to [[https://www.hitl.washington.edu/artoolkit/documentation/devstartup.htm|this]] documentation provided by the University of Washington's Human Interface Technology Lab. Below I will describe the additions that I made to the simpleTest.c file in order to track real-world coordinates.
+**Adding Variables**\\
+Add these two variable declarations after line 31 of the simpleTest.c program. These lines will allow us to print the X and Y coordinates to the screen during processing.
+<code c++>
+  char xValue[256];
+  char yValue[256];
+</code>
+It is also necessary to add some variables to the mainLoop function. Add these variable declarations after line 140. Keep in mind, xReal and yReal are dependent on what the camera displays in your view, and its real-world size.
+<code c++>
+  double xCoord;
+  double yCoord;
+  double xReal = 38.5;
+  double yReal = 26.5;
+</code>
+**Flipping Video**\\
+Since the camera setup is one that is looking down onto the table from a reversed angle, we need to flip the video both horizontally and vertically. We can achieve this by adding 15 lines of code in the main function, after line 54.
+<code c++>
+  if (flipMode & AR_GL_FLIP_V)
+      flipMode = flipMode & AR_GL_FLIP_H;
+  else
+      flipMode = flipMode | AR_GL_FLIP_V;
+  argViewportSetFlipMode(vp, flipMode);
+  if (flipMode & AR_GL_FLIP_H)
+      flipMode = flipMode & AR_GL_FLIP_V;
+  else
+      flipMode = flipMode | AR_GL_FLIP_H;
+  argViewportSetFlipMode(vp, flipMode);
+</code>
+**Removing Current Output**\\
+Befoire adding new output of the X and Y coordinates, we will want to remove the old output of the error valus and fps. To do this we just need to comment out lines 190, 194, and 195 for the fps.
+<code c++>
+  if (count % 60 == 0) {
+      //sprintf(fps, "%f[fps]", 60.0 / arUtilTimer());
+     arUtilTimerReset();
+  }
+  count++;
+  //glColor3f(0.0f, 1.0f, 0.0f);
+  //argDrawStringsByIdealPos(fps, 10, ysize - 30);
+</code>
+For the error values, comment out lines 227, 229, and 230.
+<code c++>
+  //sprintf(errValue, "err = %f", err);
+  glColor3f(0.0f, 1.0f, 0.0f);
+  //argDrawStringsByIdealPos(fps, 10, ysize - 30);
+  //argDrawStringsByIdealPos(errValue, 10, ysize - 60);
+  //ARLOG("err = %f\n", err);
+</code>
+**Adding the X & Y Coordinates**\\
+Now we need to add the data for the X and Y coordinates to the screen. We can achieve this by adding 6 lines of code to the same area we just removed code from. Add these four lines after line 226.
+<code c++>
+  xCoord = markerInfo[k].pos[0];
+  yCoord = markerInfo[k].pos[1];
+  sprintf(yValue, "Y: %f", (yReal / ysize)*yCoord);
+  sprintf(xValue, "X: %f", (xReal / xsize)*(xsize - xCoord));
+</code>
+Now add these two lines after line 232.
+<code c++>
+  argDrawStringsByIdealPos(xValue, xsize - 10, 60);
+  argDrawStringsByIdealPos(yValue, xsize - 10, 30);
+</code>
+**Changing the Graphics Models**\\
+Now that we are tracking the coordinates well, we just need to change to original 3D cube graphics into a small 3D marker. This can be achieved by simply editing two lines of code, 388 and 389.
+<code c++>
+  glTranslatef(0.0f, 0.0f, 0.0f);
+  glutSolidCube(10.0);
+</code>
+Now the program should run smoothly and with accurate prediction of the real-world coordinates of the marker. Below is a video showing the coordinate tracking program in action.
+{{ youtube>AAjSOaPMHBU?large }}\\ \\
+==== Step 7: Tracking Multiple Markers ====
+In order to use the ARToolkit SDK for tracking of objects or for any kind of computer vision application, you will often need to track more than one marker's position on the screen. One feature of the ARToolkit SDK that makes tracking multiple markers easier is their support for barcode-matrix markers. You can read more about these style of markers [[https://artoolkit.org/documentation/doku.php?id=3_Marker_Training:marker_barcode|here]]. Essentially these barcode markers use a preset definition of matrix-style barcodes that correspond to individual IDs for a marker. This allows for individual markers to be pulled out specifically, but also for easier general tracking of all markers in loops. In order to use and track these barcode-style markers, we will need to add/change the code that we used for the original tracking.
+**Changing from pattern-detection to barcode-detection**
+First you will need to remove the references to the pattern style, because we are no longer using pattern-detection. To do this, comment out the lines in the beginning of the program around line 25 (depending on your code) where it defines the pattern name, and where it initializes the pattern handle.
+  //#define       PATT_NAME     "Data/hiro.patt"
+  //ARPattHandle     *arPattHandle;
+Now you will need to add the barcode-detection to the main function. Places these two lines of code right before the function call for argMainLoop():
+  arSetPatternDetectionMode(arHandle, AR_MATRIX_CODE_DETECTION);
+  arSetMatrixCodeType(arHandle, AR_MATRIX_CODE_3x3_HAMMING63);
+This will setup the marker-detection into barcode-matrix mode, allowing the ARToolkit to detect these markers instead of the traditional style of marker.
+**Tracking Coordinates of Multiple Markers**
+In order to consistently track the coordinates of multiple markers, you will need to alter the detection algorithm to associate one barcode ID with one instance of an array for storing your coordinates. To do this, add these lines of code to the main detection loop, after the IDs and CF values are logged to the ARConsole (Please change xCoord and yCoord to arrays that have the size as the amount of markers to track (currently 8 in this example)):
+  for (h = 0; h < 7; h++) {
+    if (markerInfo[j].idMatrix == h) {
+      yCoord[h] = (yReal / ysize)*(ysize - markerInfo[j].pos[1]);
+      xCoord[h] = (xReal / xsize)*(markerInfo[j].pos[0]);
+    }
+  }
+Now we will be adding to this for loop in order to use our tracked coordinates for localization and navigation within an area.
+==== Step 8: Using Multiple Markers for Localization and Navigation ====
+In order to track the position of a robot or other vehicle using the ARToolkit, we will need to create an algorithm that creates relative coordinates for the robot based off of a known location of a stationary marker. This will allows us to create a kind of coordinate system that is independent of camera position or resolution. In order to do this, we will need to use one barcode marker (in most cases this will be number 0) fixed to a stationary location, and then reference this location in our code to get relative distances.  This can be achieved by adding this block of code to the end of the for loop from the previous step (Please declare xCoordRel and yCoordRel as arrays, with the same size as xCoord and yCoord, at the beginning to the mainLoop() function):
+  if ((xCoord[0] != 0) && (yCoord[0] != 0) && (xCoord[h] < 1000) && (yCoord[h] < 1000) && (xCoord[h] > -1000) && (yCoord[h] > -1000)) {
+    xCoordRel[h] = xCoord[h] - xCoord[0];
+    yCoordRel[h] = yCoord[h] - yCoord[0];
+    ARLOG("X(%d): %.1f; Y(%d): %.1f\n", h, xCoordRel[h], h, yCoordRel[h]);
+    sprintf(xValue[h], "X(%d): %.1f", h, xCoordRel[h]);
+    sprintf(yValue[h], "Y(%d): %.1f", h, yCoordRel[h]);
+    argDrawStringsByIdealPos(xValue[h], 10, ysize - (25 * (h+1)));
+    argDrawStringsByIdealPos(yValue[h], 130, ysize - (25 * (h+1)));
+  }
+This if statement will store the positions of these markers into a separate array for relative positions, ensuring that normal tracking is unaffected by this. This will also output those relative distances to the screen using the last 5 lines of code. Since this is located within that same for loop from above, this will keep everything sorted into the proper positions of their array. The conditional statement for this step is checking to make sure that the reference marker is stored, and that the marker it is trying to calculate for is being recognized correctly (hence the over 1000 value). Once you have added this to your code, you should  be able to efficiently and easily track multiple markers and their relative positions using the ARToolkit SDK. This has many potential applications for navigation and localization projects with robotics.
+\\
+{{ youtube>HREQoOhgJVI?large }}
+\\
 ===== Final Words =====
-This tutorial's objective was to <fill in the blank>. Complete <choose: construction details, source code and program descriptions> for <fill in the blank>. Once the concepts were conveyed the reader could <fill in the blank>.
+This tutorial's objective was to teach how to setup, and use the ARToolkit SDK for tracking and navigation. Complete source code for the coordinate tracking program can be found [[https://github.com/D-Wazzle/Potential-Fields-Navigation/blob/master/ARToolkitCoordinateTracking.cpp|here]]. Once the concepts were conveyed the reader could use the ARToolkit to write their own AR/object tracking programs in Visual C/Cpp.
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-Speculating future work derived from this tutorial, includes <fill in the blank>. In the big picture, the problem of <fill in the blank> can be solved with this tutorial.
+Speculating future work derived from this tutorial, includes Potential Fields using the ARToolkit, and Potential Fields with Humanoid Robots such as Darwin. In the big picture, the problem of object tracking can be solved with this tutorial.
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 For questions, clarifications, etc, Email: <[email protected]>