How do I draw a box using jetson-utils:cudaOverlay() in Python?

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
#1

Jetson Xavior NX, Python, jetson-utils

How do I draw a square box using cudaOverlay(). I am using python and can’t figure out how this is done. I searched the forum and didn’t find any example to do this. I read that it can be done but no clear example Python code was given.

I have a the topleft,toprignt,bottomright,bottomleft points and need to draw a rectangle with the x dimensions plus I don’t want the area to be filled in. just the outside with lines that are about 1 to 2 pixels thick.

I have a cudaimage that I want to draw these lines on. I am currently doing it in opencv, but I don’t want to convert to numpy and back , as this seems to be less efficient.

Another issue is I need to convert my color space. RGB>BGR and BGR>RGB. Can i do that using jetson-utils? I also am doing that in opencv but that is slow and I want to use the gpu to do that as well.

–Mike

#3

The cudaOverlay() function is for composting two images and not drawing rectangles. If you are using detectNet, that can overlay boxes (but they are filled, not outline). Long ago I had tried an outline-based method but it was buggy.

Yes, you can do that using the cudaConvertColor() function. For example, this will convert from RGB->BGR:

imgInput = jetson.utils.loadImage('my_image.jpg', format='rgb8')
imgOutput = jetson.utils.cudaAllocMapped(width=imgInput.width, height=imgInput.height, format='bgr8')
jetson.utils.cudaConvertColor(imgInput, imgOutput)
#4

I am using detectNet for box creation, however the boxes I want to draw are not related to detectNet’s boxes. They are for some other purpose. ie Detection zones where I want to only focus on. This is for display purposes for user to see where the detection zones are only being used. I guess What I really am looking for is a Cuda enabled library for drawing and text overlay like what OpenCV has. I would use OpenCV drawcalls if I could get the GPU performance from it. Is there a Cuda enabled library I can install that would give me drawing functions like OpenCV has? I need to use Python.

How would I convert BRG-> RGB? I need to go both ways. I can use OpenCV but I want better performance.

Thanks, Mike

#5

You would just pass in a BGR image as input and RGB image as output to cudaConverColor(), like so:

imgInput = jetson.utils.cudaAllocMapped(width=imgInput.width, height=imgInput.height, format='bgr8')
imgOutput = jetson.utils.cudaAllocMapped(width=imgInput.width, height=imgInput.height, format='rgb8')
jetson.utils.cudaConvertColor(imgInput, imgOutput)