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
Related
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.
I am trying to crop the object from its background on an image using AForge.net. I have detect the edges of the object using cannyEegeDetector, but I don's know how to crop it using the detected edges.
Do you have any ideas to crop the object from the background?
I don't know anything about the data structure that CannyEdgeDetector returns, but you probably want to treat it with an algorithm similar to contour filling in the selected area (kinda like the fill bucket in MS Paint). On each row of the images pixels, start from the left side of the image scanning right, and each time you cross a boundary, you toggle whether it's in the "fill area". Pixels in the fill area are preserved, ones outside of it are cropped. Hope that helps!
I am making a logical gates application and I can currently drag out bitmaps into the picturebox. These bitmaps are the logical gates. Now I need a way to draw the lines to connect inputs with gates. I would like to have the line sort of stick to connection or anchor points on the bitmap that I place but I have no idea how to do this.
Each bitmap dragged out is an object with a size and an x y position.
Thanks for any help! I have been searching for a solution for a while now.
I basically ended up making 10x10 rectangles positioned according to the height/width of the object that would update when the bitmap was moved. The bitmap was also its own rectangle.
Background
I want to be able to get the drawn dimensions of a zoomed image inside the picturebox (I'll explain below).
The PictureBox.ImageRectangle property seems to be exactly what I'm looking for because it shows the height and width of the resized image, as well as it's relative top, left position inside the control.
The trouble is PictureBox.ImageRectangle is private and so I can't read the values without using reflection (which is obviously not ideal).
Actual Question
My question is, is there another way that I can easily get to these values without writing a method to calculate what the values "ought" to be? I can do that easily enough, but I feel I'd be reinventing the wheel.
Context:
I'm writing a simple image processing app in C# and one of the things it has to do is allow the user to draw a selection around a portion of the image (a lot like the Marquee tool in Photoshop).
I need to know the dimensions of the rendered image so I know where to set the bounds of my marquee tool and also to translate the values of the drawn rectangle to points on the scaled bitmap inside the control.
My answer look simple so maybe I'm missing something, but I think Control.DisplayRectangle suits your need.
EDIT
OK, missed the point; however see How to get the value of non- public members of picturebox?
if you want to access dimension of the image in picture box you can use
GraphicsUnit units = GraphicsUnit.Point;
RectangleF imgRectangleF = pictureBox1.Image.GetBounds(ref units);
Rectangle imgRectangle = Rectangle.Round(imgRectangleF);
I'm building a c# app to take photos of visitors for ID badges. I have found a c# wrapper for web cams so can take a snap shot easily, however I need to set the images to a certain number of pixels ideally with the persons head filling most of the area.
I imagine the best way to do this is to allow the end user to drag out a rectangle over the initial image with fixed x and y ratio covering the persons face. This would crop the image and do any resolution adjustment necessary.
Does anyone know of an example similar to this? I think I know how to do the rectangle and get my co-ordinates for the image cropping apart from fixing an x and y ratio. Obviously an example would be quicker than trying to write my own.
As of .Net 3.0, System.Windows.Media.Imaging provides a CroppedBitmap class that inherits from BitmapSource. Its constructor takes a BitmapSource and an Int32Rect. If you pass it your original image and your rect, it will return a cropped image as a BitmapSource.