5

我试图检查图像的一部分是否存在于另一个图像中

解释:


完整图片:http:
//imageshack.us/photo/my-images/526/part1g.png/

我想检查他是否存在于完整图像中的图像的第二部分:http :
//imageshack.us/photo/my-images/706/part2p.png/

如果第二部分存在,则函数返回
true一个可以检查它是否存在的函数?


(如果它只是单个像素那么它很容易,但我想检查图像的一部分是否存在于另一个图像中)
有一个有效的代码,但它检查图像中是否存在单个像素

    Dim bmp As Bitmap = PictureBox1.Image
    For x As Integer = 0 To bmp.Width - 1
        For y As Integer = 0 To bmp.Height - 1
            If bmp.GetPixel(x, y) = Color.FromArgb(48, 48, 48) Then
                msgbox("Pixel Exist In Image!!!")
            End If
        Next
    Next
4

2 回答 2

3

我编写了这个扩展来在图像中查找图像。但是它有一些限制:1)图像必须在没有色彩空间的情况下保存(或无论如何都相同)和 2)它不适用于有损压缩图像(即 jpeg,因为你需要平均和容差执行)。

我已经优化了像素匹配例程。它没有完全调试,但似乎按预期工作。它忽略了 alpha 通道(故意,根据需要扩展),您需要尝试捕获您的调用者(即内存不足异常)。

用法:

Dim p As Point = yourBitmap.Contains(bmpYouLookFor)
If p <> Nothing Then
'...
End If

代码:如果您不想将其作为扩展名(需要 .net 3.5+),只需删除扩展名属性并将其作为普通函数调用,并将源位图作为参数。

将以下内容复制并粘贴到模块中(许可证:CC-attribution):

'*******************************************************************************
'*
'*      Epistemex
'*
'*      Bitmap extension: .Contains(bmp)
'*      KF
'*
'*      2012-09-26      Initial version
'*      2012-09-26      Minor optimization, exit for's impl.
'*
'*******************************************************************************

Imports System.Drawing
Imports System.Runtime.CompilerServices
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices

Module BitmapExtension

    <Extension()>
    Public Function Contains(src As Bitmap, ByRef bmp As Bitmap) As Point
        '
        '-- Some logic pre-checks
        '
        If src Is Nothing OrElse bmp Is Nothing Then Return Nothing

        If src.Width = bmp.Width AndAlso src.Height = bmp.Height Then
            If src.GetPixel(0, 0) = bmp.GetPixel(0, 0) Then
                Return New Point(0, 0)
            Else
                Return Nothing
            End If

        ElseIf src.Width < bmp.Width OrElse src.Height < bmp.Height Then
            Return Nothing

        End If
        '
        '-- Prepare optimizations
        '
        Dim sr As New Rectangle(0, 0, src.Width, src.Height)
        Dim br As New Rectangle(0, 0, bmp.Width, bmp.Height)

        Dim srcLock As BitmapData = src.LockBits(sr, Imaging.ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb)
        Dim bmpLock As BitmapData = bmp.LockBits(br, Imaging.ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb)

        Dim sStride As Integer = srcLock.Stride
        Dim bStride As Integer = bmpLock.Stride

        Dim srcSz As Integer = sStride * src.Height
        Dim bmpSz As Integer = bStride * bmp.Height

        Dim srcBuff(srcSz) As Byte
        Dim bmpBuff(bmpSz) As Byte

        Marshal.Copy(srcLock.Scan0, srcBuff, 0, srcSz)
        Marshal.Copy(bmpLock.Scan0, bmpBuff, 0, bmpSz)

        ' we don't need to lock the image anymore as we have a local copy
        bmp.UnlockBits(bmpLock)
        src.UnlockBits(srcLock)

        Dim x, y, x2, y2, sx, sy, bx, by, sw, sh, bw, bh As Integer
        Dim r, g, b As Byte

        Dim p As Point = Nothing

        bw = bmp.Width
        bh = bmp.Height

        sw = src.Width - bw      ' limit scan to only what we need. the extra corner
        sh = src.Height - bh     ' point we need is taken care of in the loop itself.

        bx = 0 : by = 0
        '
        '-- Scan source for bitmap
        '
        For y = 0 To sh
            sy = y * sStride
            For x = 0 To sw

                sx = sy + x * 3
                '
                '-- Find start point/pixel
                '
                r = srcBuff(sx + 2)
                g = srcBuff(sx + 1)
                b = srcBuff(sx)

                If r = bmpBuff(2) AndAlso g = bmpBuff(1) AndAlso b = bmpBuff(0) Then
                    p = New Point(x, y)
                    '
                    '-- We have a pixel match, check the region
                    '
                    For y2 = 0 To bh - 1
                        by = y2 * bStride
                        For x2 = 0 To bw - 1
                            bx = by + x2 * 3

                            sy = (y + y2) * sStride
                            sx = sy + (x + x2) * 3

                            r = srcBuff(sx + 2)
                            g = srcBuff(sx + 1)
                            b = srcBuff(sx)

                            If Not (r = bmpBuff(bx + 2) AndAlso
                                    g = bmpBuff(bx + 1) AndAlso
                                    b = bmpBuff(bx)) Then
                                '
                                '-- Not matching, continue checking
                                '
                                p = Nothing
                                sy = y * sStride
                                Exit For
                            End If

                        Next
                        If p = Nothing Then Exit For
                    Next
                End If 'end of region check

                If p <> Nothing Then Exit For
            Next
            If p <> Nothing Then Exit For
        Next

        bmpBuff = Nothing
        srcBuff = Nothing

        Return p

    End Function

End Module
于 2012-09-26T16:26:28.680 回答
0

您可以编写一个函数来遍历第二个图像的每个可能的左上角像素,然后将像素复制到另一个位图对象,然后将新的位图对象与您的第二个图像像素逐个像素进行比较。

所以首先你会遍历像素

  • x < mainImageWidth - subImageWidth
  • y < mainImageHeight - subImageHeight

如果主图像中 (x, y) 处的像素与子图像中 (0, 0) 处的像素具有相同的颜色值,则复制从 (x, y) 开始的区域,与您的尺寸相同使用类似这样的功能将主图像的子图像转换为新的位图对象 - http://msdn.microsoft.com/en-us/library/aa457087.aspx

然后只需遍历新对象和子图像中的像素,在相同坐标处比较颜色。如果遇到差异,请打破循环。如果你到了这个循环的结尾,你有一个匹配并且可以返回 True,否则继续循环遍历主图像的像素,直到你到达一个子图像不可能再适合的点,然后返回 False .

于 2012-06-19T09:32:31.573 回答