we are in the middle of project - we use USB microscope Dino Lite to take some pictures but we need to set it to specific setting. And only thing I cannot find out is how to turn off LED lights (I mean like flash light). Right now I'm like here:
import cv2
cap = cv2.VideoCapture(1)
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 2592)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1944)
cap.set(cv2.CAP_PROP_EXPOSURE, -8)
cap.set(cv2.CAP_PROP_BACKLIGHT, 0) # does not work!
result, image = cap.read()
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
I guess that
cap.set(cv2.CAP_PROP_BACKLIGHT, 0)
work with some LED but not with the 'front one' that I need to turn off...if you know what I mean.
OS WIN10/11
Try using guvcview to turn off the LED light. It should stay off when you open the camera in opencv.
Related
i got an usb cam that support "live mode" aka video and "snapshot mode".
The max resolution for snapshot mode is 4128 X 3096.
import cv2
from cv2 import CAP_DSHOW
cap = cv2.VideoCapture(0,CAP_DSHOW)
cap.set(cv2.CAP_PROP_FRAME_WIDTH, 4128)
cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 3096)
ret,frame = cap.read()
while(True):
cv2.imshow('img1',frame)
if cv2.waitKey(1) & 0xFF == ord('y'):
cv2.imwrite("c10.png",frame)
cv2.destroyAllWindows()
break
cap.release()
Doc
I tried every resolutions higher than full HD but i cannot get an image with a resolution higher than 1920*1080px.
Thanks for the help.
EDIT: Does anyone know a simple way to grab a frame from a USB camera at a desired resolution in python ? I tried a pygame example but only got a black image even if my camera is detected at [0].
I'm trying to capture photos and videos using cv2.VideoCapture and cameras with an aspect ratio of 16:9. All image is returned by OpenCV have black sidebars, cropping the image. In my example, instead of returning an image with 1280 x 720 pixels, it returns a 960 x 720 image. The same thing happens with a C920 webcam (1920 x 1080).
What am I doing wrong?
import cv2
video = cv2.VideoCapture(0)
video.set(cv2.CAP_PROP_FRAME_WIDTH, 1280)
video.set(cv2.CAP_PROP_FRAME_HEIGHT, 720)
while True:
conected, frame = video.read()
cv2.imshow("Video", frame)
if cv2.waitKey(1) == ord('s'):
video.release()
break
cv2.destroyAllWindows()
Using OpenCV:
Using Windows Camera:
I had this exact issue with a Logitech wide angle in windows camera and I was wondering about a driver problem.
So I solved it using the DirectShow driver instead of the native driver using this:
cv2.VideoCapture(cv2.CAP_DSHOW)
If you have more than one camera add the index to that value like this
cv2.VideoCapture(cv2.CAP_DSHOW + camera_index)
It will accept the desired resolution by applying the right aspect ratio without having the sidebars.
The Answer of #luismesas is completely right and worked for me.
But for people being as unskilled as I am you need to save the capture returned by cv2.VideoCapture. It is not a Parameter you can set like cv2.VideoCapture(cv2.CAP_DSHOW), it is a method.
camera_index = 0
cap = cv2.VideoCapture(camera_index, cv2.CAP_DSHOW)
ret, frame = cap.read()
Confirmed on Webcam device HD PRO WEBCAM C920.
I had the same issue too, but only on Windows 10, OpenCV 3.4 and Python 3.7.
I get the full resolution without the black side bars on a Mac OS.
I used PyGame to capture the webcam input and got the full resolution of 1920x1080 on Windows.
Just resize the received frame:
cv::Mat dst;
cv:resize(frame,dst,cv::Size(1280,720));
cv::imshow("Video",dst);
Check it!
When I take a webcam picture with python using opencv the picture gets very dark. How do I fix this?
I have tried to make it wait a few seconds after starting the camera to see if that was the problem but that didn´t work either.
import cv2
cam = cv2.VideoCapture(0)
check, frame = cam.read()
cv2.imwrite('image.png', frame)
cam.release()
*Answer en English -.-
I think it's because your webcam have too litle time to take the picture, it needs light. I do this and it works:
import cv2
webcam = cv2.VideoCapture(0)
contador = 0
while True:
check, frame = webcam.read()
cv2.imshow("Captura", frame)
key = cv2.waitKey(1)
if contador==50: #Low contador means low light
cv2.imwrite(filename='image.png', img=frame)
break
contador=contador+1
print(contador)
webcam.release()
cv2.destroyAllWindows()
We're doing a project in school where we need to do basic image processing. Our goal is to use every video frame for the Raspberry Pi and do real time image processing.
We've tried to include raspistill in our python-program but so far nothing has worked. The goal of our project is to design a RC-car which follows a blue/red/whatever coloured line with help from image processing.
We thought it would be a good idea to make a python-program which does all image processing necessary, but we currently struggle with the idea of bringing recorded images into the python program. Is there a way to do this with picamera or should we try a different way?
For anyone curious, this is how our program currently looks
while True:
#camera = picamera.PiCamera()
#camera.capture('image1.jpg')
img = cv2.imread('image1.jpg')
width = img.shape[1]
height = img.shape[0]
height=height-1
for x in range (0,width):
if x>=0 and x<(width//2):
blue = img.item(height,x,0)
green = img.item(height,x,1)
red = img.item(height,x,2)
if red>green and red>blue:
OpenCV already contains functions to process live camera data.
This OpenCV documentation provides a simple example:
import numpy as np
import cv2
cap = cv2.VideoCapture(0)
while(True):
# Capture frame-by-frame
ret, frame = cap.read()
# Our operations on the frame come here
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# Display the resulting frame
cv2.imshow('frame',gray)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()
Of course, you do not want to show the image but all your processing can be done there.
Remember to sleep a few hundred milliseconds so the pi does not overheat that much.
Edit:
"how exactly would I go about it though. I used "img = cv2.imread('image1.jpg')" all the time. What do I need to use instead to get the "img" variable right here? What do I use? And what is ret, for? :)"
ret indicates whether the read was successful. Exit program if not.
The read frame is nothing other than your img = cv2.imread('image1.jpg') so your detection code should work exactly the same.
The only difference is that your image does not need to be saved and reopened. Also for debugging purposes you can save the recorded image, like:
import cv2, time
cap = cv2.VideoCapture(0)
ret, frame = cap.read()
if ret:
cv2.imwrite(time.strftime("%Y%m%d-%H%M%S"), frame)
cap.release()
You can use picamera to acquire images.
To make it "real time", you can acquire data each X milliseconds. You need to set X depending on the power of your hardware (and the complexity of the openCV algorithm).
Here's an example (from http://picamera.readthedocs.io/en/release-1.10/api_camera.html#picamera.camera.PiCamera.capture_continuous) how to acquire 60 images per second using picamera:
import time
import picamera
with picamera.PiCamera() as camera:
camera.start_preview()
try:
for i, filename in enumerate(camera.capture_continuous('image{counter:02d}.jpg')):
print(filename)
time.sleep(1)
if i == 59:
break
finally:
camera.stop_preview()
This question is related with this one:
how to display a full screen images with python2.7 and opencv2.4
I want to display a black image full screen, i have created even a black image with the same resolution of the screen.
But i get a little white stripe on top and on the left of the screen.
I don't know if it is a problem of my screen that is not aligned or its my code. I have tried in 2 displays and the white stripe is displayed.
So if you run this code below, do you get a full black image?
import numpy as np
import cv2
if __name__ == "__main__":
img = cv2.imread('nero.jpg')
cv2.namedWindow("test", cv2.WND_PROP_FULLSCREEN)
cv2.setWindowProperty("test", cv2.WND_PROP_FULLSCREEN, cv2.cv.CV_WINDOW_FULLSCREEN)
cv2.imshow("test",img)
cv2.waitKey(0)
cv2.destroyAllWindows()
EDIT :
This method is not working for me. do you know anther way or libraries to display a full screen image?
EDIT 2: still unsolved, i am starting to think that it is an openCv bug
I have the same problem, there is a white stripe of 1 pixel on the left and on the top side of the window. Tested it with multiple monitors. OpenCV version 3.4.2
But there is a workaround which works perfectly fine in my case (see also https://gist.github.com/goraj/a2916da98806e30423d27671cfee21b6). Here's the code:
import cv2
import win32api
import win32gui
cv2.namedWindow("fullScreen", cv2.WINDOW_FREERATIO)
cv2.setWindowProperty("fullScreen",cv2.WND_PROP_FULLSCREEN,cv2.WINDOW_FULLSCREEN)
hwndMain = win32gui.FindWindow(None, "fullScreen")
rgb = win32gui.CreateSolidBrush(win32api.RGB(0, 0, 0))
GCLP_HBRBACKGROUND = -10
win32api.SetClassLong(hwndMain, GCLP_HBRBACKGROUND, rgb)
Yes I do.
img = np.zeros((900, 1600)) #my aspect ratio is 16x9
cv2.namedWindow("test", cv2.WND_PROP_FULLSCREEN)
cv2.setWindowProperty("test", cv2.WND_PROP_FULLSCREEN, cv2.cv.CV_WINDOW_FULLSCREEN)
cv2.imshow("test",img)
cv2.waitKey(0)
gives me a fully black screen. Are you sure you are using the right aspect ratio?