opencv java - detect all the rectangles and fill them with an image - java

I am currently working on a solution for an automatic image edit.
And I have used Canny Edge Detection and Closing.
But What I ultimately want to accomplish is to find all the rectangles from blueprint and fill them with an image what I have.
I want to know the process that I need to take, not the exact code or solution!
Please suggest me what steps should I take to accomplish it, thx.
Image that has the rectangles
Image that needs to go into all the rectangles
what i have done so far
2018-02-12 EDITTED(clean rectangle detected)
// I have done finding the rectangles and drawing lines over them, but the result is not really reliable than I expected(it draws line on rectangles those are not a parking space), and I do not know how to put an image on those rectangle instead of drawing line on them. please help me out!
P.S : Only in JAVA please !

In your case, you don't need Canny. Your image is really clean and edges are really visible already. A simple Threshold, will work better.
For rectangle detection take a look at this example (included with opencv) that uses findcontours and checks the angles: https://github.com/opencv/opencv/blob/master/samples/cpp/squares.cpp
In your case, you can skip the Canny step because you don't have gradients. You may need to modify the filtering, like side dimensions for your case.
Once the rectangles look good, you just need to copy your image in the location. If rectangles are rotated, you will have to rotate your image as well.
EDIT:
To copy the small image onto the big image you can do the following
Mat submatImg = bigImage.submat(new Rect(x, y, smallImage.width(), smallImage.height());
smallImage.copyTo(submatImg);
If you need to do resizing and rotations, take a look at geometric transformations

Related

How do I make 2d- Flashlight effect in Processing 3

For reference the effect I'm going for is this:
I'm working in Processing 3, NOT p5.js.
I've looked around processing forums, but i can't find anything that works in the current version or doesn't use PGraphics and a mask which from what I've read can be expensive to use.
My current ideas and implementations have resulted to drawing shapes around the player and filling the gaps in with a circles with no fill that has a large stroke weight.
Does anyone know of any methods to easily and inexpensively draw a black background over everything except a small circular area?
If this is the wrong place to ask this question just send me on my way I guess, but please be nice. Thank you:)
You could create an image (or PGraphics) that consists of mostly black, with a transparent circle in it. This is called image masking or alpha compositing. Doing a Google image search for "alpha composite" returns a bunch of the images I'm talking about.
Anyway, after you have the image, it's just a matter of drawing it on top of your scene wherever the player is. You might also use the PImage#mask() function. More info can be found in the reference.

How to Draw a continuous line on touch path in libgdx?

I tried using pixmap , but every time i draw a path and increaase drag speed , it shows space betweeen two pixmap circles.
I also tried by saving touch points in an array and drawind all the points by shaperenderer but same thing happened.
I need to draw a smooth line like in some image editor apps.
Right now using this method.
while (cIter.hasNext()) {
penpoint = cIter.next();
shapeRenderer.circle(penpoint.getPosition().x,
penpoint.getPosition().y, 3);
}
but it shows like this.
https://s3.amazonaws.com/pushbullet-uploads/ujCRdpmszeu-lp4uLBpI5MftwHBvmk58QP4w4mrzfkJx/Screenshot_2014-12-14-15-23-41.png
do not know if this is what you want, but maybe you can use it for whatever you want to do, hope it helps.
https://github.com/libgdx/libgdx/wiki/Path-interface-%26-Splines
https://github.com/libgdx/libgdx/blob/master/tests/gdx-tests/src/com/badlogic/gdx/tests/PathTest.java
P.S:maybe you can look on Beizer curves
https://www.google.es/?gws_rd=ssl#q=http://devmag.org.za+/2011/04/05+/bzier-curves-a-tutorial/

Get portion of an image using rotated Shape

From the above image if I want a portion behind the RED Rectangle I can easily get it,
but the issue I cannot get the portion behind the Yellow Rectangle because it is rotated.
So how can I get a portion of an image from a rotated shape on it?
For example my goal is to get a portion of an Image where the rectangle is located on the image. if someone rotates this rectangle by an x degree [in whatever direction] then it is getting difficult to extract the exact portion of an image after applying rotation.
Any suggestions?
Here a more lengthy description of a possible approach. I do not know the Java2D drawing API very well but if I remember correctly it has the capabilities to do what is required.
First you have to figure out the translation and rotation of the subregion you want compared to an equally size rectangle located straight in the upper left corner in the image. Then invert this transformation.
Make a graphics context which is backed by a bitmap in memory. This one should have the size of the subimage you want. Setup the inverse transformation you calculated earlier on the context and draw your image at position 0,0. As Java2D will take the transformation into account you should now get the sub image you want in the memory bitmap.
Mihir, I think you might be getting distracted by the rotation/AffineTransform aspects of this challenge and it is leading you down the wrong road. Also keep in mind that I don't totally know what you mean by "get" here -- do you want to save out the highlighted region to an image? Do you want to render it as a watermark on another image? etc... I'll just try and answer in the general case to get you down the right track.
What you want is the content from the image defined by the polygon in yellow in your image above; ignoring the fact that it looks like a rotated rectangle.
It is late and I am missing a step in here, but I think this will get you 90% of the way there and clarify the last piece (Graphics2D.setClip) that you need.
Create a java.awt.Polygon that defines the region around the area you want.
Use getBounds() or getBounds2D() to get the width/height of the bounding box required to hold this Polygon when rendered out into a rectangle. (e.g. boundingBox)
Create a new BufferedImage with these width/height values.
Get the Graphics2D from the new BufferedImage (e.g. newG2)
newG2.drawImage(originalImage, boundingBox.x, boundingBox.y, boundingBox.width, boundingBox.height)
NOTE This is where my memory is failing me; at some point you need to set the clip on newG2 (newG2.setClip(someShape)) so when the bounding box is rendered into it, you don't get the full bounding box of graphics rendered in, but instead some subset as defined by the yellow outline.
One easy way to do this is to create two Polygon's:
poly1 = a java.awt.Polygon that defines the yellow selection in the ORIGINAL image.
poly2 = a java.awt.Polygon that defines the exact same shape of Polygon, but shifted to a 0,0 origin point.
poly1 is used to get the bounding box to copy out the full bounding box that encompasses the content selected in yellow (and extra content around it)
poly2 is used to set the clip on the target Graphics2D (newG2) so when the bounding box is rendered into it, we clip back out everything outside of that Yellow shape so we just get the content in Yellow. You'll likely want to use an ARGB image type and set the background of the target image as transparent otherwise you'll get a black fill color.
I think this is the right direction for the clips; I was up to my eyeballs in Java2D for years and years but have been out of it for a while and forget if this will give you exactly what you want or not; you might need to tweak it around, but these are all the tools you need.

Java - Find a sequence of pixels

Was just wondering how you would be able to check each pixel, from top of your screen to bottom (or just a 500x500 rectangle) for a pattern of pixels in it. Example look through all the pixels, and see if there is 20 red pixels in a row (Search the screen for a red box).
Sorry for the terrible description, let me know and ill try to make it more specific.
What you are trying to do is called Template Matching in the Image Processing community, you should first check this.
For the implementation part, you can access the pixels of BufferedImage (using getRGB/getRGBs methods), or even better you can use JAI or JavaCV if you want to do anything serious.

Dividing the image and getting coordinates

I have an image with yellow background containing a random figure as shown in figure:
The random figure is divided by black lines into image pieces. Now each piece can be represented separately as a square containing that piece image with transparent background.
My question if it possible to find the coordinates of each piece algorithmically in the original image?
I am writing this application in Java.
I don't have much idea about the graphics. If its possible then please elaborate little bit.
Presuming the images look mostly like what you have here
Loop
Find a Red pixel
If found
flood fill red to non-red at this point, remembering region
create output image from this region
else
You are done
Use connected component labeling on the binary image (threshold your current image).
I used MATLAB to threshold the image, and run a labeling algorithm. Then I used region properties to find the centroid of each connected component (which are the image pieces you need). The following is the labeled image with the black stars representing the centroid of each piece:

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