Python Wrapper

[sushant1727]

After successfully running darnknet.exe in windows now I am looking forward to use Python with your implementation.

Is there a way I can use Python wrapper in windows/ubuntu with/without GPU?

Thanks
Shan

[AlexeyAB]

Yes. You can use darknet.py on Windows and Linux by using Python 2.x or 3.x:

• on Linux: run darknet/darknet.py (use LIBSO=1 in the Makefile and compile)

• on Windows: run darknet/build/darknet/x64/darknet.py (first compile darknet/build/darknet/yolo_cpp_dll.sln)

---

For detection on the video try to use Python-code like this:

def capture(thresh=.5, hier_thresh=.5, nms=.45, configPath = "./cfg/yolov3.cfg", weightPath = "yolov3.weights", metaPath= "./data/coco.data", showImage= True, makeImageOnly = False, initOnly= False):
    global metaMain, netMain, altNames #pylint: disable=W0603
    netMain = load_net_custom(configPath.encode("ascii"), weightPath.encode("ascii"), 0, 1)  # batch size = 1
    metaMain = load_meta(metaPath.encode("ascii"))
    
    num = c_int(0)
    pnum = pointer(num)
    num = pnum[0]

    capture = cv2.VideoCapture(0)
    print(capture.get(cv2.CAP_PROP_FPS))
    
    capture.set(cv2.CAP_PROP_FRAME_WIDTH, 1024)
    capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 768)

    while True:
        ret, frame = capture.read()
        im, arr = array_to_image(frame)
        predict_image(netMain, im)
        dets = get_network_boxes(netMain, im.w, im.h, thresh, hier_thresh, None, 0, pnum, 1)
        if nms:
            do_nms_sort(dets, num, metaMain.classes, nms)
        res = []
        for j in range(num):
            for i in range(metaMain.classes):
                if dets[j].prob[i] > 0:
                    b = dets[j].bbox
                    nameTag = metaMain.names[i]
                    res.append((nameTag, dets[j].prob[i], (b.x, b.y, b.w, b.h)))
        print(res)
        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

    capture.release()
    cv2.destroyAllWindows()

if __name__ == "__main__":
    print(capture())

Perhaps you should optimize this function to avoid too much CPU-usage:

darknet/darknet.py

Lines 195 to 205 in c1bb8c1

	def array_to_image(arr):
	import numpy as np
	# need to return old values to avoid python freeing memory
	arr = arr.transpose(2,0,1)
	c = arr.shape[0]
	h = arr.shape[1]
	w = arr.shape[2]
	arr = np.ascontiguousarray(arr.flat, dtype=np.float32) / 255.0
	data = arr.ctypes.data_as(POINTER(c_float))
	im = IMAGE(w,h,c,data)
	return im, arr

[sushant1727]

You're awesome, I will try this.
Since I was looking for Python Wrapper I also found PyhtonWrapper Yolo3-4-Py.

[MyVanitar]

The python wrapper does not have speed decrease?

[sushant1727]

I haven't tried the AlexeyAB wrapper but I have the Yolo3-4-Py. With CPU it runs at max 1 FPS and with GPU it should near to 10 FPS(As suggested by developer).
I will get back here and share how much FPS I get with AlexeyAB wrapper.

[sushant1727]

Hey Alex, I am back to bug you again. I compiled the yolo_cpp_dll without any errors but getting these errors when running darknet.py.

python darknet.py

Traceback (most recent call last):
File "darknet.py", line 109, in
raise ValueError("NoDLL")
ValueError: NoDLL

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "darknet.py", line 119, in
lib = CDLL(winGPUdll, RTLD_GLOBAL)
File "C:\Program Files\Python 3.5\lib\ctypes_init_.py", line 347, in init
self._handle = _dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found

[AlexeyAB]

@sushant1727 What of these 2 files did you run?

• on Linux: run darknet/darknet.py

• on Windows: run darknet/build/darknet/x64/darknet.py

Is yolo_cpp_dll.dll file near with your darknet.py?

[sushant1727]

@AlexeyAB:
On windows I am in the darknet.py directory and ran python darknet.py

I copied the file "yolo_cpp_dll.dll" and got this new error.

Traceback (most recent call last):
File "darknet.py", line 110, in
lib = CDLL(winGPUdll, RTLD_GLOBAL)
File "C:\Program Files\Python 3.5\lib\ctypes_init_.py", line 347, in init
self._handle = _dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found

[AlexeyAB]

@sushant1727

On windows I am in the darknet.py directory

1. What is the darknet.py directory?
2. Is there a file yolo_cpp_dll.dll?

[sushant1727]

Directory is C:\Users..\Desktop\darknet-master>python darknet.py

06/08/2018 03:52 PM 964,608 yolo_cpp_dll.dll
27 File(s) 169,749,927 bytes
11 Dir(s) 69,967,814,656 bytes free

[AlexeyAB]

@sushant1727 Run:

C:\Users..\Desktop\darknet-master\build\darknet\x64>python darknet.py

[hj3yoo]

Yes. You can use darknet.py on Windows and Linux by using Python 2.x or 3.x:

• on Linux: run darknet/darknet.py (use LIBSO=1 in the Makefile and compile)
• on Windows: run darknet/build/darknet/x64/darknet.py (first compile darknet/build/darknet/yolo_cpp_dll.sln)

For detection on the video try to use Python-code like this:

def capture(thresh=.5, hier_thresh=.5, nms=.45, configPath = "./cfg/yolov3.cfg", weightPath = "yolov3.weights", metaPath= "./data/coco.data", showImage= True, makeImageOnly = False, initOnly= False):
    global metaMain, netMain, altNames #pylint: disable=W0603
    netMain = load_net_custom(configPath.encode("ascii"), weightPath.encode("ascii"), 0, 1)  # batch size = 1
    metaMain = load_meta(metaPath.encode("ascii"))
    
    num = c_int(0)
    pnum = pointer(num)
    num = pnum[0]

    capture = cv2.VideoCapture(0)
    print(capture.get(cv2.CAP_PROP_FPS))
    
    capture.set(cv2.CAP_PROP_FRAME_WIDTH, 1024)
    capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 768)

    while True:
        ret, frame = capture.read()
        im, arr = array_to_image(frame)
        predict_image(netMain, im)
        dets = get_network_boxes(netMain, im.w, im.h, thresh, hier_thresh, None, 0, pnum, 1)
        if nms:
            do_nms_sort(dets, num, metaMain.classes, nms)
        res = []
        for j in range(num):
            for i in range(metaMain.classes):
                if dets[j].prob[i] > 0:
                    b = dets[j].bbox
                    nameTag = metaMain.names[i]
                    res.append((nameTag, dets[j].prob[i], (b.x, b.y, b.w, b.h)))
        print(res)
        cv2.imshow('frame', frame)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break

    capture.release()
    cv2.destroyAllWindows()

if __name__ == "__main__":
    print(capture())

Perhaps you should optimize this function to avoid too much CPU-usage:

darknet/darknet.py

Lines 195 to 205 in c1bb8c1

def array_to_image(arr):
import numpy as np
# need to return old values to avoid python freeing memory
arr = arr.transpose(2,0,1)
c = arr.shape[0]
h = arr.shape[1]
w = arr.shape[2]
arr = np.ascontiguousarray(arr.flat, dtype=np.float32) / 255.0
data = arr.ctypes.data_as(POINTER(c_float))
im = IMAGE(w,h,c,data)
return im, arr

I've copypasted capture() into darknet.py, and simply changed the bottom two lines:

if __name__ == "__main__":
    print(capture())

When I ran this code, nothing was detected:

python darknet.py

Here's the result from the same video using the executable:

./darknet detector demo data/coco.data cfg/yolov3.cfg yolov3.weights ../data/test3.mp4

The same thing happens when I use my custom model cfg and weights to test.

ADD: Just to clarify, I understand that the image is supposed to be displayed without bounding box. I can just add couple of cv2.rectangle() for that.

However, the program just doesn't detect anything at all - res is empty, and num is 0.

[willSapgreen]

( If the following resolution is not related, please let me know and I will remove this comment )
To resolve OSError: [WinError 126] The specified module could not be found issue,
I notice that I need to put all opencv related dlls, pthreadGC2.dll, and pthreadVC2.dll within the folder where yolo_cpp_dll.dll is located.

Windows 7 + Visual Studio 2015 + OpenCV 2.4.13

[bit-scientist]

@willSapgreen Hi, I have the same error on my PC, Win 10, x64, opencv 3.4.0, CUDA 10, python 3.5.4.
The only difference is I am running darknet_video.py copied from here into build/darknet/x64

Traceback (most recent call last):
  File "darknet_video.py", line 57, in <module>
    lib = CDLL("./libdarknet.so", RTLD_GLOBAL)
  File "C:\python354\lib\ctypes\__init__.py", line 351, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: [WinError 126] The specified module could not be found

My yolo_cpp_dll.dll is located in build/darknet/x64 and there are pthreadGC2.dll, pthreadVC2.dll and opencv related dlls (opencv_ffmpeg340.dll, opencv_ffmpeg340_64.dll, opencv_world340.dll, opencv_world340d.dll ) from C:\opencv340\opencv\build\x64\vc14\bin

Could you help me as well? thanks.

[WefPok]

@hj3yoo Hi! Have you solved this problem? I also got empty results...