I have an image processing question, using C#.
Say I have some schematic diagrams in BMP format, the diagram contains component shapes which are connected to each other.
I wrote a simple program to detect square shapes in the diagram as one component, and record the location of it. However, the next level is to detect more complicated shapes like a few arcs joined together. Note that these shapes can be different sizes in the image. Does anyone know any good method of doing it? without downloading any library (this is my limitation now).
After detecting the shapes, I also need to record which shape is connected to which, so later on, I can redraw them. I have one week to do this, so thanks a lot for any help!!
I'm using C#.
Have a look at this paper. My understanding of their approach:
Detect edges
Detect corners by looking for perpendicular edges
Detect polygons by looking for groups of corners
Detect circles using Hough transform
This is a fairly difficult research problem. Even with a powerful computer vision library like OpenCV, implementing an effective solution within 1 week would be a demanding task.
Have you taken a look at using EmguCV? It is an open-source C# wrapper of OpenCV. It also has a shape detection sample you might interested in.
To answer an old post I had, I have done what I needed to do in 2 weeks time, it worked well. I actually ended up using different algorithms for different shapes. The algorithms are a bit self inventions, but a good method I want to mention is that get the histogram and then use projection on different axis helped a lot.
Related
These days I am trying to develop two algorithms in c#. Self Organizing Map, Particle Swarm Optimization and Glowworm Swarm optimization. I know how the algorithms work but there is an issue which I am not sure where to start from.
Agents in the search space which try to find the best solution have some coordinates(x and y). I don't know how am I should represent the position of agents visually in a form in each iteration. One option may be using charts in c# and represent point so that in each iteration I am going to change the position of the agent(point) in the chart. Another way may be using drawing classes in c# and drawing circles or points in a panel based on the x and y coordinates. Which classes of .net should I use to represents points in a search space visually(in a 2D space).
I hope you understood me and thank you for reading this post.
If your design variables are N-dimensional, N>3, it is not an easy job to visualize the entire domain of interest. You can either project the N-Dim to 2D or 3D to get a "section" of the fields.
I have a bitmap image like this
My requirement is to create a GUI to load the image and for changing the contrast and other things on the image and algorithm to mark the particular area in silver colour as shown in the fig using C++ or C#.I am new to image processing and through my search I have found out that I can use the Histogram of the image for finding the required area.These are the steps.
Get the histogram
Search for intensity difference
Search for break in the line
Can someone suggest me how can I proceed from here.Can I use Opencv for this or any other efficient methods are available..?
NOTE:
This image have many bright points and the blob algorithm is not successful.
Any other suggestions to retrieve the correct coordinates of the rectangle like object.
Thanks
OpenCV should work.
Convert your input image to greyscale.
adaptiveThreshold converts it to black and white
Feature detection has a whole list of OpenCV feature detectors; choose one depending on the exact feature that you're trying to detect.
E.g. have a look at the Simple Blob Detector which lists the basic steps needed. Your silver rectangle certainly qualifies as "simple blob" (no holes or other hard bits)
If all of your pictures look like that, it seems to me not complicate to segment the silver area and find its centre. Basically you will need to apply these algorithms in the sequence below:
I would suggest binaryze the image using Otsu adaptive threshold algorithm
Apply a labelling (blob) algorithm
If you have some problem with noise you can use an opening filter or median before the blob algorithm
If you end up with only one blob (with the biggest area I guess) use moment algorithm to find its centre of mass. Then you have the X,Y coordinate you are looking for
These algorithms are classical image processing, I guess it wouldn't be hard to find then. In any case, I may have they implemented in C# and I can post here latter in case you think they solve your problem.
May be a research on Directshow, a multi media framework from Microsoft will help you to accomplish your task.
i have 4 shapes in image
i want to get pixels of one shape in list of point
the shapes have same color
List<point> GetAllPixelInShape(point x)
{
//imp
}
where x point of this shape
Long story short, you could begin with a connected components / region labeling algorithm.
http://en.wikipedia.org/wiki/Connected-component_labeling
In OpenCV you can call findContours() to identify contours, which are the borders of your connected regions.
http://dasl.mem.drexel.edu/~noahKuntz/openCVTut7.html
OCR is an extremely difficult task, especially for a script like Arabic. Creating an OCR algorithm from scratch takes a lot of work and numerous algorithms working together. OCR for machine printed text is hard enough. Implementing an algorithm to read handwriting is not something I'd suggest trying until you have a year or two of image processing experience. If you haven't read textbooks and academic papers on OCR, you're likely to spend a lot of time reproducing work that has already been done.
If you're not familiar with contour tracing and/or blob analysis, then working with OpenCV may not be a good first step. Since you have a specific goal in mind, you might first try different algorithms in a user-friendly GUI that will save you coding time.
Consider downloading ImageJ so that you can see how the algorithms work. There are plugins for a variety of common image processing algorithms.
http://rsbweb.nih.gov/ij/
Your proposed method signature doesn't provide enough information to solve this. Your method will need to know the bounds of your shape, how long and wide it is etc, ideally a set of points that indicate those bounds.
Once you have those, you could potentially apply the details of this article, in particular the algorithms specified in the answer to solve your problem.
I am making an object tracking application. I have used Emgucv 2.1.0.0
to load a video file
to a picturebox. I have also taken the video stream from a web camera.
Now, I want
to draw an unfilled square on the video stream using a mouse and then track the object enclosed
by the unfilled square as the video continues to stream.
This is what people have suggested so far:-
(1) .NET Video overlay drawing(DirectX) - but this is for C++ users, the suggester
said that there are .NET wrappers, but I had a hard time finding any.
(2) DxLogo sample
DxLogo – A sample application showing how to superimpose a logo on a data stream.
It uses a capture device for the video source, and outputs the result to a file.
Sadly, this does not use a mouse.
(3) GDI+ and mouse handling - this area I do not have a clue.
And for tracking the object in the square, I would appreciate if someone give me some research paper links to read.
Any help as to using the mouse to draw on a video is greatly appreciated.
Thank you for taking the time to read this.
Many Thanks
It sounds like you want to do image detection and / or tracking.
The EmguCV ( http://www.emgu.com/wiki/index.php/Main_Page ) library provides a good foundation for this sort of thing in .Net.
e.g. http://www.emgu.com/wiki/index.php/Tutorial#Examples
It's a pretty meaty subject with quite a few years and different branches of research associated with it so I'm not sure anyone can give the definitive guide to such things but reading up neural networks and related topics would give you a pretty good grounding in the way EmguCV and related libraries manage it.
It should be noted that systems such as EmguCV are designed to recognise predefined items within a scene (such as a licence plate number) rather than an arbitory feature within a scene.
For arbitory tracking of a given feature, a search for research papers on edge detection and the like (in combination with a library such a EmguCV) is probably a good start.
(You also may want to sneak a peek at an existing application such as http://www.pfhoe.com/ to see if it fits your needs)
I have a fairly simple situation. I just don't know any specific terms to search for.
I have a single image, in that image I have several other images that follow a basic pattern.
They are rectangles and will possibly have landmark image to base things off of.
An important part, is that I need to detect rotated/mis-scaled sub-images.
Basically what I need to be able to do is split 'business cards' from a single image into properly aligned single images.
As I am also designing the cards to be scanned I can put in whatever symbol or something that would make detection easier (as I said a landmark)
If your example is representative (which I doubt for some reason) then Hough transform is your friend (google it, there are plenty of explanations and code around). With it you'll be able to detect the rectangles.
Some examples of Hough transform in C# are http://www.koders.com/csharp/fid3A88BC1FF95FCA9D6A182698263A40EE7883CF26.aspx and http://www.shedletsky.com/hough/index.html
If what actually happens is that you scan some cards, and you have some control over the process, then I'd suggest that you ensure there is no overlap between cards, and provide a contrasting background (something very different from the cards). Then any edge-detection will get you close enough to what you've drawn in your example, and after that you can use Hough transform.
Alternatively, you can implement the paper http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.59.4239 which uses Hough transform to detect rectangles directly, without edge detection.
If I did not understand your problem, or you need clarifications, please edit your question further and post a comment on this answer.
Try AForge.NET (if you are using C#). It has DocumentSkewChecker which will calculate the angle of rotated image.
You can try ExhaustiveTemplateMatching class of AForge.Net