i have an image processing application that is able to getpixel, anyone know how can i hide or show the RGB channel of my image? For example when i click a button call "RED" it will hide red channel and show only blue and green. i m using C# btw
thanks alot
Try the AForge.NET library. Use the AForge.Imaging.Filters.ChannelFiltering filter.
Allocate a blank image (1 channel) of the same size as the original image. Then, when handling a button press for RED, do the following:
split your original image into R, G and B
compose a new image using blank, G, B (in that order, as the order of channels is important). This leaves out the red channel
display the composed image
Handle button presses for BLUE and GREEN in similar fashion.
split, compose and display methods are common in imaging libraries. Their exact names may differ depending on the library you are using, but their overall functionality should generally be the same. By the way, what library are you using? You didn't mention it in your question.
If you're not using any library to achieve what you're doing, you will have to write your own split and compose functions (or something along those lines). You would have to say more about the data structures you are using to get help in that direction.
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 am trying to implement my own monochrome/black and white filter in C# to scan text documents. My approach is to apply a threshold filter on the captured image. However, I often run into the problem that the varying brightness on the image causes a ''shadowing effect'' on the processed image. Refer to the link below (it is pretty blurry but it should suffice). The image to the far left is the original image. When I apply my threshold filter, I get the same result as the image in the middle; some of the text becomes unreadable because the brightness of the image varies, so some portions become really black or really white. However, with the right filter, you can obtain the processed image to the right where everything looks crystal clear.
https://www.google.dk/search?q=monochrome+image+processing&espv=2&biw=1706&bih=859&source=lnms&tbm=isch&sa=X&ved=0ahUKEwir8vXlhIzPAhUFiywKHeSBC1wQ_AUIBigB#imgrc=4UTzoIpyqTkwrM%3A
I would like to know what the process is to obtain the image to the far right. Another example can be seen in the image below. It shows a sample mobile PDF scanner in use. Scanning the image results in a very nice black and white image, where the text can be easily read and no ''shadowing'' occurs on the image. Does anyone know what this process is or what it is called? It is very often used in mobile PDF scanning applications. Thank you in advance.
EDIT: The filter is called ''Adaptive Thresholding''. You can use the BradleyLocalThresholding class to implement the filter, or you can write it yourself (which is what I did). Please refer to my response to the comment by Yves Daoust down below.
You need two ingredients.
One is "background reconstruction", i.e. retrieving the intensity of the white sheet "under the characters", for instance by morphological opening.
The other is "shading correction", i.e. compensating the unevenness of the background illumination by comparing to the reconstructed background, for instance by subtraction.
This will "flatten" the image, making it perfectly amenable to global thresholding.
A simple method is to convert the image to grayscale and then convert it to B/W using an error diffusion algorithm such as Floyd–Steinberg dithering.
I am trying to write a simple program that lets me overlay a dot on top of an image when the image is clicked. I can save the X and Y data back to my database but then I will want to be able to call that information back at a later date and overlay the dots again via code unlike the first time when the user had to click the image.
I got as far as capturing the X and Y of the click no problem but I am having trouble finding examples specifically for what I am trying to do. All of the examples online seem to be for saving the image with the added graphic but I do not need to do that as it will be the same image every time.
Once I can do this, I also need to work out a way that I can detect what area of the image has been clicked. The areas I need to mark out vary in shape and size so I need to try and work out a way to 'map' these areas and then cross reference with the co-ordinates of the users click (I assume that I may need to do some clever geometry stuff for that?)
If anyone has any suggestions of what subjects/classes/methods etc. to research for either of my queries, I would very grateful.
Thanks in advance
You can use the System.Drawing namespace to achieve this.
Create a control and override OnPaint and OnPaintBackground. Store your clicks in a List
In OnPaintBackground, draw the image using DrawImageUnscaled using the graphics object which is passed to you as a parameter.
In OnPaint, loop through your points array and call graphics.FillElipse or similar to draw a little dot.
Because this isnt a retained mode graphics system, you need to keep drawing these items so this may not suit a large number of dots. In that case, you can create an in memory bitmap and get a graphics drawing object using graphics.FromImage.
i will need to print an "x" according to the coordinates given to me from one of the tables in my database. im probably gonig to use c# to connect to mysql.
i will probably have a winform that is 8.5 x 11 inches (The size of a regular sheet of paper) and i will populate the entire thing with labels of "x" and they will be invisible.
each individual table record will have the coordinates of those labels which should NOT be invisible
the form for every record will show and will print. the printing will be on top of a paper that is actually a physical application itself.
the problem:
how to fill out a physical application using data from a mysql database. (dont tell me that i should be printing the entire app from scratch, the reason this is not possible is because the form is actually TRIPLE paper width (white, yellow, and pink copy), so i cannot print the entire app from scratch, i have to print on top of it.
the question: how do i print "x" at specified regions? is my solution the best way to go or is there a smarter approach?
in case you have no idea what i am talking about, here are some related questions:
ms-access: designing a report: printing text on specific x,y coordinates
Conditional formatting in Access
While labels would offer you the ability to make an X show up I don't feel that having a bunch of hidden labels is the best way.
Does the "application" represent some kind of form? Are you looking to "check-off" boxes using x's and then print this?
I may suggest using GDI+ (drawing) vs using labels.
Consider the following:
Locate the coordinates for your boxes. Then use the drawstring method within an overridden onPaint event-handler for your form or for the panel which may represent your form's canvas.
This article talks about GDI+ and how to draw text as graphics.
http://www.functionx.com/vb/gdi+/objects/fonts.htm
I'm trying to find some info about removing an image background "automagically" if possible in .NET.
Actually I could not find much data and I don't event know if it's possible or are there any API components available.
Any ideas?
Establish a rule, for example that the pixel at [0,0] must be the 'transparent' color (the background). Load the image as a Bitmap (let's call it bmp), and then do something like this:
bmp.MakeTransparent(bmp.GetPixel(0, 0));
Homer, for the file formats you suggest, there is no easy way of defining what the 'background' is. For instance, say you have some colorful text on a white background. I'm assuming you'd want to make the white transparent? There is nothing in the file format to say "this layer or color is the background". There may be heuristics for trying to determine the background color, but there will probably be no library to do something like image.MakeBGTransparent().