This may seem like a strange question, but I have a set of pictures I want to use as a fading screen saver, and I want each picture to have an accompanying quote, but each quote will be in a different place, relative to the picture.
Rather than coding a Rectangle for the area of each image, it would be easier just to draw a rectangle in the image, and have it drawn in there.
Now, the drawn shape would be a stark, uniform coloured border (lime green, for instance) because the colour doesn't appear in the pictures, and it would be on a solid coloured background, like black for instance.
My question is: If I draw a lime green rectangle on each image, how could I then, using C#, find that rectangle in the image, get the dimensions of it, and replace the lime green with the background colour, so in the end product, it'd look like the shape was never there to begin with?
I have not tried anything, I have no code to show, because it's an idea I had and though I'm sure it must be possible, I don't even know what to start searching for.
I hope this is possible, if it isn't, then I'll just draw a rectangle for each one, but that's a last resort. :)
Have you thought about using either the emgucv or aforge libraries? They are able to detect shapes in images quite easily. Though they don't detect edges perfectly, if all you want to detect is a rectangle, either one should work well.
Here are two tutorials on shape detection for emgu cv and aforge. Once you have the shape detected, then you can easily cut it out for the background. Say, for example, that you used the aforge Detection of quadrilaterals (in the link), then you could easily get the rectangles position and size by the calling of blobs[i].Rectangle; and create a rectangle with same size and position with picture background color.
If you need more clarification please feel free to comment. Nice idea!
Related
I have no experience with images. I have to detect simple object in static image. For example I have image like:
I want to detect edges and remove background. Just to compare them.
Something like this.
Do u have any solutions of this problem? Images have often white backgrounds.
I've just thought about detect edges, and take everything what they contains.
To segment out the shoe-
Anadptive Threshold to remove the smooth changing background.
Sobelx, which removes the apparent background line, which i assume is
common for images of this setup.
dilate, closing operation to separate out the shoe.
Find contours, bounding box etc as per your choice.
Do an additional threshold if you want to remove the shadow at the bottom.
I'm able to fill a rectangle with an image and i apply a mask on top of the image using this code
args.DrawingSession.FillRectangle(rect, imgRnd, mask);
i need to apply some transform to this image, i'am able to do that with no issue, but i have encounter a strange issue, the last pixel is repeated.
i have used
imgRnd.ExtendX = CanvasEdgeBehavior.Wrap;
imgRnd.ExtendY = CanvasEdgeBehavior.Wrap;
and the image is repeated continuously.
My question is : there is a way to draw one time the image disabling and ExtendX and ExtendY?
FillRectangle will always fill all the pixels within the specified rectangle. The edge behavior enum controls what value they are filled with if the image is positioned such that it does not completely cover the rectangle being drawn.
How exactly are you transforming the image? Can you change that to also transform the rectangle itself, so you won't be trying to fill pixels that aren't covered by the image?
Another option is to use image effects (Microsoft.Graphics.Canvas.Effects namespace) which give much more detailed control than FillRectangle over how multiple images are transformed, combined, etc.
Similar to my previous question which I as yet have not solved (Comparing Frames of a live Feed) I have another issue.
Scenario
I have an image taken by a camera that contains a rectangle in it. I need to crop the image to only show the rectangle plus a small margin.
My Efforts
I have accomplished this by iterating through the pixels using LockBits and attempting to find potential edges but these seems terribly slow and inefficient
My Thoughts
I was thinking I could take an empty image as a baseline and then remove the differences between the two, however I cannot be sure that the lighting will be exactly the same and that potential contaminants such as an accidental fly getting into the image will not be present which could muck up this process.
Is there any easier way? The rectangle should (usually) be in the bottom left corner, but not always (long story) but this cant be relied upon.
My Environment
Visual Studio 2012 (2010 if neccessary is available)
Ueye camera
C#
The images are of type System.Drawing.Bitmap
The rectangle will often be something like a credit card or an ID card or anything of a similar size and shape
The empty image (background) looks like this:
Using EmguCV you can detect shapes such as a rectangle. Click here for the emgu code. Once you have detected the rectangle it is fairly easy to crop it out using a new Bitmap with the size of the rectangle.
The sample demonstrates how to crop the image from specific Picturebox control into destination Picturebox control using mouse selection or specified coordinates.
1.How to use mouse to select an area (rectangle) in a Picturebox control.
2.How to crop the image by the rectangle.
http://code.msdn.microsoft.com/windowsdesktop/CSWinFormCropImage-d4beb1fa
There's a neat little library called YLScsDrawing that allows you to skew a bitmap between four corners, and then draw it. Unfortunately, whenever I attempt this, my rectangular bitmap always has incredibly aliased edges, even with IsBilinearInterpolation = True. How could I go about changing this library so that it antialiases the edges?
An example of what I mean can be found below. Look at the top of the green line.
I want to set an image to have a transparent background, but I do not want to replace all pixels of a specific colour with transparency.
To be more specific, the image is a thumbnail image for a folder, obtained via IShellItemImageFactory.GetImage. This gives me a Bitmap, as displayed in Windows Explorer thumbnail view, but the background is solid white.
I can use Bitmap.MakeTransparent on it, and that will work in most cases, but in any cases where the thumbnail image contains white itself (for example, a folder that contains images, which include white colours).
Incidently, this is the first time in over 10 years as a developer that, after googling my question, I have not found an answer anywhere, and I've actually had to ask it myself. (I think that means I just levelled up! Yippee, I am now a level 2 developer...)
Use flood-fill algorithm to fill pixels of the same color from the OUTSIDE as you need it. It is something similar to magic wand in photoshop.
http://en.wikipedia.org/wiki/Flood_fill
What I would do is flood-fill with some obscure color (Magenta always does it for me), then replace that color with transparent (I don't know if flood filling with transparent pixels is feasible).
So what you're getting from IShellItemImageFactory.GetImage is a composite image that contains the original image on a white background? I suspect the white background is there if the image doesn't have the same aspect ratio as the thumbnail size. For example, if you ask for a 96x96 thumbnail of a 640x480 image, there's going to be some white space at top and bottom.
If that's the case, you have a problem. You can't differentiate between white pixels that are contained in the image, and white pixels that are added by GetImage.
There are a few things you could do. You could load the image and resize it yourself. That's probably the easiest. You'd want to maintain your own thumbnail cache then.
Or you could examine the image returned by GetImage to look for white space on the sides. Basically, if every pixel on a row (or column) is white, then make that row (or column) transparent. It's a little more complicated than that (the NBA logo, for example). But that's essentially what you'd want to do.