I have an image that is 6400 × 3200, while my screen is 1280 x 800. Therefore, the image needs to be resized for display only. I am using Python and OpenCV 2.4.9. According to OpenCV Documentation,
If you need to show an image that is bigger than the screen resolution, you will need to call namedWindow("", WINDOW_NORMAL) before the imshow.
That is what I am doing, but the image is not fitted to the screen, only a portion is shown because it's too big. I've also tried with cv2.resizeWindow, but it doesn't make any difference.
import cv2
cv2.namedWindow("output", cv2.WINDOW_NORMAL) # Create window with freedom of dimensions
# cv2.resizeWindow("output", 400, 300) # Resize window to specified dimensions
im = cv2.imread("earth.jpg") # Read image
cv2.imshow("output", im) # Show image
cv2.waitKey(0) # Display the image infinitely until any keypress
This question is related to
python
image
opencv
image-processing
imshow
Try this:
image = cv2.imread("img/Demo.jpg")
image = cv2.resize(image,(240,240))
The image
is now resized. Displaying it will render in 240x240.
Looks like opencv lib is pretty sensitive to parameters passed to the methods. The following code worked for me using opencv 4.3.0:
win_name = "visualization" # 1. use var to specify window name everywhere
cv2.namedWindow(win_name, cv2.WINDOW_NORMAL) # 2. use 'normal' flag
img = cv2.imread(filename)
h,w = img.shape[:2] # suits for image containing any amount of channels
h = int(h / resize_factor) # one must compute beforehand
w = int(w / resize_factor) # and convert to INT
cv2.resizeWindow(win_name, w, h) # use variables defined/computed BEFOREHAND
cv2.imshow(win_name, img)
Use this for example:
cv2.namedWindow('finalImg', cv2.WINDOW_NORMAL)
cv2.imshow("finalImg",finalImg)
In opencv, cv.namedWindow() just creates a window object as you determine, but not resizing the original image. You can use cv2.resize(img, resolution) to solve the problem.
Here's what it displays, a 740 * 411 resolution image.
image = cv2.imread("740*411.jpg")
cv2.imshow("image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()
Here, it displays a 100 * 200 resolution image after resizing. Remember the resolution parameter use column first then is row.
image = cv2.imread("740*411.jpg")
image = cv2.resize(image, (200, 100))
cv2.imshow("image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()
The other answers perform a fixed (width, height)
resize. If you wanted to resize to a specific size while maintaining aspect ratio, use this
def ResizeWithAspectRatio(image, width=None, height=None, inter=cv2.INTER_AREA):
dim = None
(h, w) = image.shape[:2]
if width is None and height is None:
return image
if width is None:
r = height / float(h)
dim = (int(w * r), height)
else:
r = width / float(w)
dim = (width, int(h * r))
return cv2.resize(image, dim, interpolation=inter)
Example
image = cv2.imread('img.png')
resize = ResizeWithAspectRatio(image, width=1280) # Resize by width OR
# resize = ResizeWithAspectRatio(image, height=1280) # Resize by height
cv2.imshow('resize', resize)
cv2.waitKey()
Try with this code:
from PIL import Image
Image.fromarray(image).show()
Source: Stackoverflow.com