我进行了很多搜索以删除不需要的空间，但找不到。我只找到了可以用来删除黑白背景空间的链接。但我的背景图像可以是任何东西。所以，如果我有这些图片，
如何提取我需要的图像部分。例如，
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这是我对您的问题的解决方案：
我已经声明了一个获取原始图像的方法，然后它通过检查提供的 Image 的角来查找背景颜色，如果至少 3 个角具有相似的颜色（最多 10% 偏移），那么我们就找到了背景颜色它试图在图像中找到那些形状的边界，这些形状的颜色当然与背景颜色不同
找到边界后，函数裁剪图像并将新的裁剪区域作为新的位图返回！
这是演示文件：下载
完整解决方案：下载
以下是 的结果：
Image 1：
Image 2：
Image 3：
ImageProcessingTools这是Simplified类中的函数，
public class ImageHelper
{
#region CropUnwantedBackground
public static Bitmap CropUnwantedBackground(Bitmap bmp)
{
var backColor = GetMatchedBackColor(bmp);
if (backColor.HasValue)
{
var bounds = GetImageBounds(bmp, backColor);
var diffX = bounds[1].X - bounds[0].X + 1;
var diffY = bounds[1].Y - bounds[0].Y + 1;
var croppedBmp = new Bitmap(diffX, diffY);
var g = Graphics.FromImage(croppedBmp);
var destRect = new Rectangle(0, 0, croppedBmp.Width, croppedBmp.Height);
var srcRect = new Rectangle(bounds[0].X, bounds[0].Y, diffX, diffY);
g.DrawImage(bmp, destRect, srcRect, GraphicsUnit.Pixel);
bmp.Dispose();
return croppedBmp;
}
else
{
bmp.Dispose();
return null;
}
}
#endregion
#region Private Methods
#region GetImageBounds
private static Point[] GetImageBounds(Bitmap bmp, Color? backColor)
{
//--------------------------------------------------------------------
// Finding the Bounds of Crop Area bu using Unsafe Code and Image Proccesing
Color c;
int width = bmp.Width, height = bmp.Height;
bool upperLeftPointFounded = false;
var bounds = new Point[2];
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
c = bmp.GetPixel(x, y);
bool sameAsBackColor = ((c.R <= backColor.Value.R * 1.1 && c.R >= backColor.Value.R * 0.9) &&
(c.G <= backColor.Value.G * 1.1 && c.G >= backColor.Value.G * 0.9) &&
(c.B <= backColor.Value.B * 1.1 && c.B >= backColor.Value.B * 0.9));
if (!sameAsBackColor)
{
if (!upperLeftPointFounded)
{
bounds[0] = new Point(x, y);
bounds[1] = new Point(x, y);
upperLeftPointFounded = true;
}
else
{
if (x > bounds[1].X)
bounds[1].X = x;
else if (x < bounds[0].X)
bounds[0].X = x;
if (y >= bounds[1].Y)
bounds[1].Y = y;
}
}
}
}
return bounds;
}
#endregion
#region GetMatchedBackColor
private static Color? GetMatchedBackColor(Bitmap bmp)
{
// Getting The Background Color by checking Corners of Original Image
var corners = new Point[]{
new Point(0, 0),
new Point(0, bmp.Height - 1),
new Point(bmp.Width - 1, 0),
new Point(bmp.Width - 1, bmp.Height - 1)
}; // four corners (Top, Left), (Top, Right), (Bottom, Left), (Bottom, Right)
for (int i = 0; i < 4; i++)
{
var cornerMatched = 0;
var backColor = bmp.GetPixel(corners[i].X, corners[i].Y);
for (int j = 0; j < 4; j++)
{
var cornerColor = bmp.GetPixel(corners[j].X, corners[j].Y);// Check RGB with some offset
if ((cornerColor.R <= backColor.R * 1.1 && cornerColor.R >= backColor.R * 0.9) &&
(cornerColor.G <= backColor.G * 1.1 && cornerColor.G >= backColor.G * 0.9) &&
(cornerColor.B <= backColor.B * 1.1 && cornerColor.B >= backColor.B * 0.9))
{
cornerMatched++;
}
}
if (cornerMatched > 2)
{
return backColor;
}
}
return null;
}
#endregion
#endregion
}
这是 ASP.NET 中的一个简单用法，
if (IsPostBack && Request.Files.Count > 0)
{
var file = Request.Files[0];
var bmp = new Bitmap(file.InputStream);
var croppedBmp = ImageHelper.CropUnwantedBackground(bmp);
Response.ContentType = file.ContentType;
croppedBmp.Save(Response.OutputStream, ImageFormat.Jpeg);
Response.End();
}
最后我要提一下，这些很棒的教程在图像处理方面帮助了我很多：
希望能帮助到你 ：）
于 2013-06-17T09:58:34.323 回答
4
这是一种更可靠的方法，它使用 Sobel 能量过滤器和快速边界框检测例程（从ImageResizer的WhitespaceTrimmer 插件中提取）。
namespace ImageResizer.Plugins.WhitespaceTrimmer {
public class BoundingBoxFinder {
/// <summary>
/// Returns a rectangle inside 'lookInside' that bounds any energy greater than 'threshold'.
/// </summary>
/// <param name="image"></param>
/// <param name="lookInside">A rectangle of 'image' to look inside. </param>
/// <param name="threshold">1-255, the energy threshold to detect activity. 80-150 is a good range.</param>
/// <returns></returns>
public Rectangle FindBoxSobel(Bitmap originalImage, Rectangle lookInside, byte threshold) {
Bitmap image = originalImage;
try {
//Convert if needed (makes an extra copy)
if (image.PixelFormat != PixelFormat.Format24bppRgb &&
image.PixelFormat != PixelFormat.Format32bppArgb &&
image.PixelFormat != PixelFormat.Format32bppRgb) {
image = AForge.Imaging.Image.Clone(image, PixelFormat.Format24bppRgb);
}
//Crop if needed (makes an extra copy unless we converted too, then only 1 extra copy)
if (!lookInside.Equals(new Rectangle(0, 0, image.Width, image.Height))) {
Bitmap oldImage = image;
try {
image = new Crop(lookInside).Apply(image);
} finally {
if (oldImage != originalImage) oldImage.Dispose(); //Dispose the cloned
}
}
//Makes 1 more copy at 1/3rd the size, in grayscale
Rectangle result = FindBoxSobel(image, threshold);
return new Rectangle(lookInside.X + result.X, lookInside.Y + result.Y, result.Width, result.Height);
} finally {
if (image != originalImage) image.Dispose();
}
}
/// <summary>
/// Requires 24 bit or 32 bit (A) RGB image.
/// </summary>
/// <param name="rgb"></param>
/// <param name="threshold"></param>
/// <returns></returns>
public Rectangle FindBoxSobel(Bitmap rgb, byte threshold) {
using (Bitmap gray = Grayscale.CommonAlgorithms.Y.Apply(rgb)) {
//Apply sobel operator to grayscale image
new SobelEdgeDetector().ApplyInPlace(gray);
//Threshold into black and white.
new Threshold(threshold).ApplyInPlace(gray);
//Trim only exact black pixels
// lock source bitmap data
BitmapData data = gray.LockBits(new Rectangle(0, 0, gray.Width, gray.Height), ImageLockMode.ReadOnly, gray.PixelFormat);
try {
return FindBoxExactGrayscale(data, 0);
} finally {
gray.UnlockBits(data);
}
}
}
/// <summary>
/// Returns a bounding box that only excludes the specified color.
/// Only works on 8-bit images.
/// </summary>
/// <param name="sourceData"></param>
/// <param name="colorToRemove">The palette index to remove.</param>
/// <returns></returns>
public Rectangle FindBoxExactGrayscale(BitmapData sourceData, byte indexToRemove) {
if (sourceData.PixelFormat != PixelFormat.Format8bppIndexed) throw new ArgumentOutOfRangeException("FindBoxExact only operates on 8-bit grayscale images");
// get source image size
int width = sourceData.Width;
int height = sourceData.Height;
int offset = sourceData.Stride - width;
int minX = width;
int minY = height;
int maxX = 0;
int maxY = 0;
// find rectangle which contains something except color to remove
unsafe {
byte* src = (byte*)sourceData.Scan0;
for (int y = 0; y < height; y++) {
if (y > 0) src += offset; //Don't adjust for offset until after first row
for (int x = 0; x < width; x++) {
if (x > 0 || y > 0) src++; //Don't increment until after the first pixel.
if (*src != indexToRemove) {
if (x < minX)
minX = x;
if (x > maxX)
maxX = x;
if (y < minY)
minY = y;
if (y > maxY)
maxY = y;
}
}
}
}
// check
if ((minX == width) && (minY == height) && (maxX == 0) && (maxY == 0)) {
minX = minY = 0;
}
return new Rectangle(minX,minY,maxX - minX + 1, maxY - minY + 1);
}
}
}
于 2013-06-18T15:31:01.117 回答