问题描述
我有这个工作,但它在 jpeg 图像上太慢了,还需要一些改变.
I have this one working but it is so damn slow on jpeg images and also needs some changing.
我需要知道图像中的各个颜色(RGB 的容差为 +/- 1)以及该颜色在图像中的百分比.
I need to know the individual colours in an image (with a tolerance of +/- 1 for RGB) and the % of the image that is that colour.
所以如果图像是黑白的,它会说类似白色:74%黑色:26%
so if an image was black and white it would say something like White : 74% Black : 26%
下面的代码像我说的那样工作,但我还需要添加一个容差系统,我不知道该怎么做.
The code below works like I said but I need to add a tolerance system as well and I have no idea on how I would do that.
private Dictionary<string, string> getPixelData(Bitmap image) { Dictionary<string, string> pixelData = new Dictionary<string, string>(); //int col, row; //int r, g, b; Color pixel; double offset = 0.000001; int hmm = (image.Height * image.Width); double current = 0; offset = 100 / double.Parse(hmm.ToString());// 0.01;// 100 / (image.Height * image.Width) * 10000; try { for (int i = 0; i < image.Height; i++) { for (int j = 0; j < image.Width; j++) { current = current + offset; pixel = image.GetPixel(i, j); pixelData.Add(i + "," + j, (pixel.R.ToString() + " " + pixel.G.ToString() + " " + pixel.B.ToString())); pBarprocess.Value = int.Parse(Math.Floor(current).ToString()); pBarprocess.Update(); Application.DoEvents(); } } } catch (Exception ex) { MessageBox.Show("Unable to parse image " + ex); } return pixelData; }
其他功能
private void btnProcess_Click(object sender, EventArgs e) { pBarprocess.Value = 0; pBarprocess.Enabled = false; Bitmap foo = Bitmap.FromFile(@txtFileName.Text) as Bitmap; Dictionary<string, string> pixelData = new Dictionary<string, string>(); lblProcess.Text = "Processing pixel map"; pixelData = getPixelData(foo); lblProcess.Text = "Calculating Density"; lblProcess.Update(); var distinctList = pixelData.Values.Distinct().ToList(); Console.WriteLine("DL = " + distinctList.Count); double offset = 100 / double.Parse(distinctList.Count.ToString()); double current = 0; foreach (var value in distinctList) { IEnumerable<string> query = pixelData.Values.Where(fruit => fruit == value); double perc = (double.Parse(query.Count().ToString()) / double.Parse(pixelData.Count.ToString())) * 100; Console.WriteLine(value + " = " + query.Count() + "(" + perc + "%)"); txtAnalysis.Text = "Colour " + value + " : " + query.Count() + " (" + perc.ToString() + "%) " + txtAnalysis.Text; txtAnalysis.Update(); pBarprocess.Value = int.Parse(Math.Floor(current).ToString()); pBarprocess.Update(); Application.DoEvents(); } lblProcess.Text = "Finished."; pBarprocess.Value = 0; pBarprocess.Enabled = false; }
推荐答案
GetPixel 并不是访问图像数据的真正快捷方式.使用 LockBits 方法.
GetPixel is not really a fast way to access image data. Use the LockBits method.
好吧,您正在用字符串做很多事情.以这种方式构建 pixelData Dictionary 非常无用,为什么不立即处理不同的颜色?颜色是一个不可变的结构体,所以它已经是我们字典的一个很好的键了.
Well you're doing a lot of things with strings. Building the pixelData Dictionary that way is pretty useless, why don't you process the distinct colors right away? Color is an immutable struct, so that's a good key for our dictionary already.
Dictionary<Color, int> frequency = new Dictionary<Color, int>(); for (int i = 0; i < image.Height; i++) { for (int j = 0; j < image.Width; j++) { pixel = image.GetPixel(i, j); if (frequency.ContainsKey(pixel)) frequency[pixel]++; else frequency.Add(pixel, 1); } } // and finally int totalPixels = image.Width * image.Height; foreach (var kvp in frequency) { Console.WriteLine("Color (R={0},G={1},B={2}): {3}", kvp.Key.R, kvp.Key.G, kvp.Key.B, kvp.Value / (double)totalPixels); }
这应该可以,除非您想使其更快并使用 LockBits 而不是 GetPixel.
And that should do it, except when you want to make it even faster and use LockBits instead of GetPixel.
其他一些观察:
int hmm = (image.Height * image.Width); double offset = 100 / double.Parse(hmm.ToString());
您使用了一种非常奇怪且缓慢的从 int 转换为 double 的方法.你可以只写 double offset = 100/(double)hmm; 并且它是一样的(你也可以写 100.0 而不是 100,编译器会为你创建一个 double 所以你不需要投嗯).
You're using a very strange and slow way of casting from int to double. You can just write double offset = 100 / (double)hmm; and it's the same (you could also write 100.0 and not 100 and the compiler will create a double for you so you don't need to cast hmm).
这让我笑了:
IEnumerable<string> query = pixelData.Values.Where(fruit => fruit == value);
为什么是水果!?好像你从某个地方复制了这个.
Why fruit!? Seems like you copied this from somewhere.