emguCV- how to position an Image over another image - opencv

I want to add an image over another image in emguCV at specific position. Addweighted() don't allow positioning. Is there any way i can position the image.
for example i have an image1 of 640x480 and i want to add a drop of water 10x30 on image1 at position 60x200. Is there any possible way to achieve this?

You can do the same thing as in this post with EmguCV function. In fact, just select a ROI and copy your second image to this ROI. Then, cancel the ROI.
Hope it helps!

Related

How to remove the area outside of the selected contour OpenCV

I have some pictures like this:
enter image description here
After choosing the contour that I want by index by the function cv2.findContours: enter image description here
I want to remove the nearly white background outside this contour. I tried this method: Removing background color from image opencv python but I don't know how to modify the mask such that the inner area of the contour is white and the outer is back.
Could anyone tell me how? Thanks in advance

Mask/crop an image

What is the best approach to display a cropped/masked image in Flutter?
Lets say I have one image with a mask (eg. an irregular star shape with transparent background) and the other image which I want to mask with this star, so that only the part inside the star of original image would be rendered.
I'm aiming for something like PorterDuffXfermode on Android (similar question here - Android how to apply mask on ImageView?).
In case of simple mask shapes is going the RenderClipOval way a good approach?
I would just paint it using a CustomPainter, setting the Paint.BlendMode on the Paint you pass to the method when you paint the image.
See https://docs.flutter.io/flutter/dart-ui/Canvas/drawImageRect.html and https://docs.flutter.io/flutter/dart-ui/Paint/blendMode.html and https://docs.flutter.io/flutter/widgets/CustomPaint-class.html.

Detect blurred part of an image

I have an image in the image view. When user taps on the image, it makes a part of the image blur. This part is working fine (as expected). But, if the part if already blurred then I do not want it to be blurred further. Can you give me a clue on how it can be achieved ? Consider any general image.
Either keep the original image and the blurred image separately as Alexander suggests, or keep a mask that lets you track what parts of the image have already been blurred, and mask away the already-blurred areas before applying your blur filter again.
Does the image have to blur by being touched or can it just look like it is? What if you loaded the original image on top of a blurred version of the image and erased the top layer on touch? Kind of renders your blurring function useless though.
It's a pretty hacky way to do it, but unless you want to keep track of a list of every pixel that was altered like Alexander said, I can't think of another way. That way you can just apply the blur to the already unaffected ones.

Create new image using just some pixels data from the source image based on them color

I have original image and I can cycle all pixels using #patrick-rutkowski answer here. Also I have this answer seems to create image with pixel data. But I can't understand how to combine these two answers. So the first task is get pixel and second is add it to another CGImage. For example if I want to extract all red pixels from the original image and add these red pixels to another image. I suppose it's way to go.

How to add rain effect to a picture?

Given a picture, I would like to modify it to create the effect of rain on glass. What steps should I take to achieve this goal?
Suppose we want to add the effect of a single drop of water on a given point in an image, some pixels around that point should be modified in some way: how these pixels should be modified?
Simple way is to just make transparent image that is actually image overlay. That looks like common approach of water drop effects in gimp.
example:
http://natural-drops.deviantart.com/art/drop-of-rain-373710307
I think that in order to make optically correct image one need to have full 3D info of environment, because most optics equations that one needs to simulate correct image includes each object distance.

Resources