C# Tutorial
C# Tutorial: How To Create Image Zero Padding
Zero padding an image is useful when we’re convolving it with a filter of certain size. How much padding should we use depends on how big our filter is. What is the purpose...
Related Articles
Filter by Category
- C# Tutorial(85)
- C# Image Processing(69)
- Morphological Processes(20)
- Image Processing(16)
- Image Restoration and Reconstruction(16)
- Image Segmentation(13)
- C# Data Structures And Algorithms(11)
- Color Image Processing(8)
- Frequency Domain Filtering(8)
- Image Noise(6)
- Grayscale Morphology(5)
- Thresholding(4)
- Order-Statistic Filters(4)
- Mean Filters(4)
- Sorting Algorithms(4)
- Morphological Reconstruction(3)
- Edge Detection(3)
- Simple Lists(2)
- RGB to HSI Color Model(2)
- Adaptive Filters(2)
- Tone and Color Corrections(2)
- Linked Lists(2)
- Stacks(1)
- Queues(1)
- Point Detection(1)
- Line Detection(1)
- C# Arrays(1)
- Region Segmentation Using Superpixels(1)
- Region Segmentation With K Means Clustering(1)
- Region Splitting And Merging(1)
- Sorted Lists(1)
- Region Growing Segmentation(1)
- Digital Image Watermarking(1)
- Using Color In Image Segmentation(1)
- Social Games(1)
- Bandreject Filters(1)
- Bandpass filters(1)
- Notch Filters(1)
- Landing Pages(1)
- Intensity Slicing and Color Coding(1)
- Color Slicing(1)
- Histogram Processing Color Images(1)
- Color Image Smoothing And Sharpening(1)
- C# Basics(1)
Back to Latest Articles
C# Tutorial
C# Tutorial: How To Use Gamma Correction
Gamma correction is a process, which allows you to set the brightness of screen. You can often run into this setting in video games, where you set the brightness of your screen...
C# Tutorial
C# Tutorial: How To Create An Image Negative
A negative image is a complete inversion of an image, we would say to be normal. In other words, dark areas will appear light, and light areas will become dark. More in detail, a...
C# Tutorial
C# Tutorial: How To Create Gaussian Blur
Gaussian blur is an image processing operation, that reduces noise in images. It does so by a convolution process, using a matrix that contains values calculated by a Gaussian...
C# Tutorial
C# Tutorial: How To Apply Erosion To An Image
Erosion is a morphological process, where pixels at an object boundaries are removed. Erosion and dilation are a pair of basic morphological transformations, which are completely...
C# Tutorial
C# Tutorial: How To Apply Dilation To An Image
Dilation is a simple morphology process which changes pixel intensities based on the change of intensities that occur at object boundaries. This process is used on grayscale...
C# Tutorial
C# Tutorial: How To Apply Sobel Operator To An Image
What is sobel operator? Well, basically it’s 2 kernels, with which we can process an image in a way, that only edges are visible. It is commonly used for grayscale images,...
C# Tutorial
C# Tutorial: How To Apply Contrast Stretch To An Image
Contrast stretch or otherwise known as normalization is a process where your image’s intensity is changed in such a way, that dark pixels become darker and light pixels...
C# Tutorial
C# Tutorial: How To Convert a Color Image To Grayscale
Grayscale images are basically black and white images. These images are good for programming, since their pixels hold only intensity values or in other words, shades of gray, they...
Landing Pages
Image optimization – Why and How [blog]
Why is image optimization important? There are a few different image formats that you can choose from to display it on your website. But it is not all the same even if it may look...
C# Tutorial: How To Create Image Zero Padding
Zero padding an image is useful when we’re convolving it with a filter of certain size. How much padding
should we use depends on how big our filter is.
What is the purpose of zero padding?
When we put our kernel at the very edge of our image, some of it will hang off the image. So to prevent any errors we pad the image with zeros around it. The padding thickness is usually the distance from kernel center to its edge.
Obviously this process is not super necessary, because we could just convolve the image without it.
But the end result would yield a border that wouldn’t be processed. This is not noticable if our kernel is 3×3 or 5×5 and our image is of very large size. These example kernels would leave borders of 1 pixel and 2 pixel thick. Noticability of such borders depends also on what kind of kernel or filter are we using.
So to prevent any unwanted borders we use padding (sometimes reffered also as zero padding).
Padding size explained above is reffered to as minimal zero padding.
We can use larger padding of course. Common padding size is twice the each dimensions of the image we are processing (width, height).
Padding an image has its uses, but remember to crop the image when you finish processing it.
Code for padding function
private Bitmap Pad(Bitmap img, int border)
{
int w = img.Width;
int h = img.Height;
int wp = w + 2 * border;
int hp = h + 2 * border;
Bitmap ri = new Bitmap(wp, hp);
BitmapData rd = ri.LockBits(new Rectangle(0, 0, wp, hp),
ImageLockMode.WriteOnly, PixelFormat.Format32bppArgb);
BitmapData id = img.LockBits(new Rectangle(0, 0, w, h),
ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
int imgb = id.Stride * id.Height;
int borb = rd.Stride * rd.Height;
byte[] imga = new byte[imgb];
byte[] bora = new byte[borb];
for (int i = 3; i < borb; i += 4)
{
bora[i] = 255;
}
Marshal.Copy(id.Scan0, imga, 0, imgb);
img.UnlockBits(id);
for (int y = 0; y < h; y++)
{
for (int x = 0; x < w; x++)
{
int ip = y * id.Stride + x * 4;
int rp = y * rd.Stride + x * 4;
for (int i = 0; i < 3; i++)
{
bora[(rd.Stride + 4) * border + rp + i] = imga[ip + i];
}
}
}
Marshal.Copy(bora, 0, rd.Scan0, borb);
ri.UnlockBits(rd);
return ri;
}
This post is acompanied by entire code for this project available for download here.
Comments
What i do not understood is actually how you are now not really much more well-favored than you might be now. You’re very intelligent. You recognize thus considerably on the subject of this subject, produced me in my view imagine it from a lot of numerous angles. Its like men and women are not interested unless it’s something to do with Lady gaga! Your individual stuffs nice. Always deal with it up!
Excellent post. Keep posting such kind of information on your blog. Im really impressed by it.
I think this is among the most significant information for me. And i am glad reading your article. But want to remark on some general things, The site style is perfect, the articles is really nice : D. Good job, cheers
Hello there, I discovered your web site by way of Google even as looking for a similar subject, your site came up, it looks great. I have bookmarked it in my google bookmarks.
Quality posts is the important to invite the users to go to see the web page, that’s what this web site is providing.
Right here is the perfect site for everyone who really wants to understand this topic. You realize so much its almost tough to argue with you (not that I really will need to…HaHa). You definitely put a new spin on a subject which has been discussed for a long time. Great stuff, just excellent!
What i do not realize is in reality how you’re no longer really much more well-liked than you may be now. You are very intelligent. You know therefore considerably when it comes to this topic, made me in my opinion believe it from so many various angles. Its like men and women aren’t fascinated unless it’s something to do with Girl gaga! Your personal stuffs great. Always handle it up!
Actually no matter if someone doesn’t understand then its up to other users that they will help, so here it takes place.
This page definitely has all the information and facts I wanted concerning this subject and didn’t know who to ask.
In fact no matter if someone doesn’t know after that its up to other visitors that they will assist, so here it occurs.
Great article! That is the type of information that are supposed to be shared around the net. Disgrace on Google for no longer positioning this put up upper! Come on over and discuss with my web site . Thanks =)
Do you have a spam issue on this blog; I also am a blogger, and I was curious about your situation; many of us have created some nice practices and we are looking to exchange methods with other folks, please shoot me an email if interested.
My coder is trying to convince me to move to .net from PHP. I have always disliked the idea because of the expenses. But he’s tryiong none the less. I’ve been using Movable-type on numerous websites for about a year and am worried about switching to another platform. I have heard fantastic things about blogengine.net. Is there a way I can import all my wordpress posts into it? Any help would be greatly appreciated!
Greate post. Keep posting such kind of information on your page. Im really impressed by it.
Howdy! This post could not be written any better! Looking at this article reminds me of my previous roommate! He constantly kept talking about this. I am going to forward this post to him. Pretty sure he’s going to have a great read. Many thanks for sharing!
I’m curious to find out what blog platform you are utilizing?
I’m experiencing some small security issues with my latest site and I would like to find something more safeguarded.
Do you have any suggestions?
Very soon this website will be famous among all blogging people, due to it’s good articles
I must say you have very interesting posts here.
Your page can go viral. You need initial traffic only.
How to get it? Search for; Miftolo’s tools go viral
Appreciation to my father who shared with me on the topic of this blog, this website is
truly awesome.
I enjoy what you guys are up too. This kind of clever work and
exposure! Keep up the awesome works guys I’ve included you guys to my own blogroll.
Hi there would you mind letting me know which webhost you’re using?
I’ve loaded your blog in 3 different browsers and I must say this blog loads a lot faster then most.
Can you suggest a good hosting provider at a fair price?
Many thanks, I appreciate it!