FastPointCloud example in the Azure Kinect SDK

wajih youssef 40

So I am debugging the fastpointcloud example in the azure kinect SDK on visual studio and I want to ask whether when the kinect detectes an object and gives back its coordinates like shown before if I change the direction of the camera why doesnt the values change ( for the height y for example ) ? does it give all the coordiantes of points of the first object it detectes until the debug is finished ? thanks

point_cloud_data[i].xyz.x = xy_table_data[i].xy.x * (float)depth_data[i];
point_cloud_data[i].xyz.y = xy_table_data[i].xy.y * (float)depth_data[i];
point_cloud_data[i].xyz.z = (float)depth_data[i];

LeelaRajeshSayana-MSFT 14,831 Reputation points Microsoft Employee

2023-01-20T22:48:13.2266667+00:00

Hi Wajih, Welcome to Microsoft Q&A forum! Thank you for posting the question. Could you please provide references to any resources you might have used in building and debugging the application. I would also like to know if you have put any logger statements in the code before this step indicating that the code is in fact running whilst in debug mode.
wajih youssef 40 Reputation points

2023-01-23T16:56:33.38+00:00

Hello @LeelaRajeshSayana-MSFT and thanks for asnwering,

In fact, I started by importing the fastpointcloud example in the azure kinect SDK ( C:\Users\Lenovo x270\Desktop\kinect\Azure-Kinect-Sensor-SDK-develop\examples\fastpointcloud) into a new visual studio IDE project ( latest version). Then I followedthe steps provided here [https://video2.skills-academy.com/en-us/azure/kinect-dk/add-library-to-project to add the <k4a/k4a.h> library using the nuget Package Manager in the visual studio IDE ( I installed the Microsoft.Azure.Kinect.Sensor. package) which allowed me to build the example with no errors and finally I proceeded with debugging my code and I even got the generated file which contained the coordinates of detected points ( I checked with the coordinates sysytems provided here : [https://video2.skills-academy.com/en-us/azure/kinect-dk/coordinate-systems). of course I connected my Azure kinect to my pc and tested with different objects and positions and each time checked with the generated file. the issue is, as I told you I modified the code a bit to acquire the heighest detected point and printed it, but when I change the position of the kinect the value doesn't change ( I have to start a new debug to get the new value I print using a simple printf).

thank you
wajih youssef 40 Reputation points

2023-01-24T09:14:33.38+00:00

This is an extra comment which was posted by mistake ( as I couldn't delete it )
LeelaRajeshSayana-MSFT 14,831 Reputation points Microsoft Employee

2023-01-27T16:10:57.21+00:00
Hi @wajih youssef Greetings! I am following up to see if you got a chance to review the below provided information on debugging the application. Please let me know if you need any further assistance with this issue.

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Accepted answer

LeelaRajeshSayana-MSFT 14,831 Reputation points Microsoft Employee

2023-01-26T00:55:06.8833333+00:00
Hi Wajih, thank you for sharing the additional requested details. Could you please confirm if this is the GitHub repository your application is based on -- Fast point Cloud I don't see any loop in the code which lets it track the changes dynamically from the Azure Kinect device. Line 201 in the code is responsible for invoking the function to generate point cloud and it has a few parameters which are generated using the k4a commands. Please refer the line below

depth_image = k4a_capture_get_depth_image(capture); if (depth_image == 0) { printf("Failed to get depth image from capture\n"); goto Exit; } generate_point_cloud(depth_image, xy_table, point_cloud, &point_count);

I would recommend putting a break point on the lines of code where the parameters for the function generate_point_cloud are measured and change the direction of the camera before the parameters are calculated to see if the code detects the change. Please note that the above code is not designed to respond to changes on Azure Kinect and the code exits after calculating the point cloud. For testing and debug purposes you can put a goto statement at Line 151 and call it after calibrating cloud point from Line 204 to validate if the code is responding to the changed Azure Kinect coordinates.

Please let me know if the above information is helpful.
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wajih youssef 40 Reputation points

2023-01-30T14:23:12.5533333+00:00

Hello @LeelaRajeshSayana-MSFT , thanks for your answer,

yes, indeed that's the GitHub repository my application is based on. In fact I added few lines of code for the previous mentionned functionality ( getting heighest detected height ) :

with defined Xmin, Xmax, Zmin and Zmax.

*point_count = 0; for (int i = 0; i < width * height; i++) { if (depth_data[i] != 0 && !isnan(xy_table_data[i].xy.x) && !isnan(xy_table_data[i].xy.y)) { point_cloud_data[i].xyz.x = xy_table_data[i].xy.x * (float)depth_data[i]; point_cloud_data[i].xyz.y = xy_table_data[i].xy.y * (float)depth_data[i]; point_cloud_data[i].xyz.z = (float)depth_data[i]; if ((Xmin< (point_cloud_data[i].xyz.x) < Xmax) && (Zmin<(point_cloud_data[i].xyz.z)<Zmax)) { if ((-point_cloud_data[i].xyz.y) > H) { H = (-point_cloud_data[i].xyz.y); } printf("H = %f\n", H); (*point_count)++;

I tried as you suggested and indeed the code doesn't detect changes dynamically from the Azure Kinect device. so we can assume that this example gives the coordinates of only one object at a time. Do you suggest any other example that would allow me to get object coordiantes dynamically ? thank you

LeelaRajeshSayana-MSFT 14,831 Reputation points Microsoft Employee

2023-01-30T22:57:44.3433333+00:00

Hi Wajih, thank you for your response and I appreciate the feedback. I am not sure if there is any approach to get data during run time. However, you can probably try the following and see if that works. Put a Label as soon as your main function starts and refer that label with the goto command after the line of code write_point_cloud. Once the code execution reaches the label change the Azure Kinect DK device orientation to where you would need it and continue the program execution. Kindly note that the program would not detect any changes after a calibration has started.
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