I would like the solution to be limited to OpenCV and/or Numpy. The only thing that would need to be changed is that at the moment it is hard coded to display the PNG image on layer 1. As a side note, I did try the cv2.addWeighted method but that yielded even worse results. Perhaps my method of blending transparent PNG with semi-transparent shapes is far from ideal. It seems that alpha is not blended at all which results in original image pixels being only fully opaque or fully transparent. However, upon closer inspection, we can observe strange behaviour when mixing alpha channels (marked with arrows): We have our input image with a semi-transparent rectangle in the middle. Output = cv2.convertScaleAbs(overlay * mask + image * (1 - mask))Īt first glance it looks acceptable. Overlay = np.zeros((imgHeight, imgWidth, 4), dtype = "uint8") # create empty overlay layer with 4 channels
Overlay images with transparency python code#
Here's my code that I have so far: # get image dimensions To overlay two images in python, a solution is to use the pillow function paste (), example: from PIL import Image import numpy as np img Image.open ('datamask13542030.png') background Image.open ('background13542030.png') background.paste (img, (0, 0), img) background.save ('howtosuperimposetwoimages01. That input image is stored in the image variable. That image is loaded with a standard cv2.IMREAD_UNCHANGED flag so that alpha channel is perfectly preserved. Here's an example input image I am using:
Img = img.convert("RGB") # Remove alpha for saving in jpg format.I would like to add a semi-transparent rectangle filled with a solid colour to an already loaded semi-transparent PNG. Img = Image.alpha_composite(img, overlay) # Alpha composite these two images together to obtain the desired result. Overlay = Image.new('RGBA', img.size, TINT_COLOR+(0,))ĭraw = ImageDraw.Draw(overlay) # Create a context for drawing things on it.ĭraw.rectangle(((llx, lly), (urx, ury)), fill=TINT_COLOR+(OPACITY,)) # semi-transparent version of the square on it. # to a fully transparent (0% opaque) version of the tint color, then draw a
Anywhere that layer is 255, the overlay image is 100 transparent and the background (webcam) will show through, Anywhere that layer is 0, the overlay image is 100 opaque and will fully conceal the background (webcam) image. An image containing what you want to overlay on top of the first using some level of alpha transparency. Channels 0,1,2 are the RGB values in the overlay image, whereas channel 3 is the alpha (transparency) layer. Here's some code: import cv2 Open overlay image, and its dimensions overlayimg cv2.imread ('1W7HZ.png', cv2.IMREADUNCHANGED) h, w. some position, and in that ROI, you again use Boolean array indexing to set all pixels to some color, i.e. Due to the model, I don't want to add an extra alpha layer in the source image. What's left to do, is setting up some region of interest (ROI) in the 'background' image w.r.t. The overlay should be transparent enough so as to be able to view the object behind the overlay.
# Make a blank image the same size as the image for the rectangle, initialized In order to construct a transparent overlay, you need two images: Your original image. I want to overlay color over a particular object for semantic segmentation. # drawn rectangle when drawing rectangles. # Calculate upper point + 1 because second point needs to be just outside the # Determine extent of the largest possible square centered on the image. With BytesIO(urlopen(url).read()) as file: Note that it supports semi-transparent squares other than black. You can do it by creating a temporary image and using Image.alpha_composite() as shown in the code below.
Overlay images with transparency python download#
Download Python source code: layerimages.py. Layer Images Layer images above one another using alpha blending. Sorry, the comment I made about it being a bug was incorrect, so. Blend transparency with color in 2D images.
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