bitmap - Vb.Net Check If Image Existing In Another Image -

i tried check if part of image existing in image

explanation:

full image:
http://imageshack.us/photo/my-images/526/part1g.png/

second part of image want check if existing in full image:
http://imageshack.us/photo/my-images/706/part2p.png/

if second part exist function return true
there function can check if exist?


(if single pixel verey easy, want check if part of image existing in image)
there code works , check if single pixel exist in image:

    dim bmp bitmap = picturebox1.image     x integer = 0 bmp.width - 1         y integer = 0 bmp.height - 1             if bmp.getpixel(x, y) = color.fromargb(48, 48, 48)                 msgbox("pixel exist in image!!!")             end if         next     next 

i wrote extension find image within image. has couple of limitations though: 1) images must saved without color-space (or same ones anyways) , 2) not work lossy-compressed images (ie. jpeg, need averaging , tolerance implementation).

i have optimized pixel matching routine. it's not debugged, seem work expected. ignores alpha-channel (on purpose, extend needed) , need try-catch on caller (ie. out-of-memory exception).

usage:

dim p point = yourbitmap.contains(bmpyoulookfor) if p <> nothing '... end if 

the code: if don't want have extension (which requires .net 3.5+) remove extension attribute , call ordinary function source bitmap argument instead.

copy , paste following module (license: 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 bitmap, byref bmp bitmap) point         '         '-- logic pre-checks         '         if src nothing orelse bmp nothing return nothing          if src.width = bmp.width andalso src.height = bmp.height             if src.getpixel(0, 0) = bmp.getpixel(0, 0)                 return new point(0, 0)             else                 return nothing             end if          elseif src.width < bmp.width orelse src.height < bmp.height             return nothing          end if         '         '-- prepare optimizations         '         dim sr new rectangle(0, 0, src.width, src.height)         dim br new rectangle(0, 0, bmp.width, bmp.height)          dim srclock bitmapdata = src.lockbits(sr, imaging.imagelockmode.readonly, pixelformat.format24bpprgb)         dim bmplock bitmapdata = bmp.lockbits(br, imaging.imagelockmode.readonly, pixelformat.format24bpprgb)          dim sstride integer = srclock.stride         dim bstride integer = bmplock.stride          dim srcsz integer = sstride * src.height         dim bmpsz integer = bstride * bmp.height          dim srcbuff(srcsz) byte         dim bmpbuff(bmpsz) byte          marshal.copy(srclock.scan0, srcbuff, 0, srcsz)         marshal.copy(bmplock.scan0, bmpbuff, 0, bmpsz)          ' don't need lock image anymore have local copy         bmp.unlockbits(bmplock)         src.unlockbits(srclock)          dim x, y, x2, y2, sx, sy, bx, by, sw, sh, bw, bh integer         dim r, g, b byte          dim p point = nothing          bw = bmp.width         bh = bmp.height          sw = src.width - bw      ' limit scan need. corner         sh = src.height - bh     ' point need taken care of in loop itself.          bx = 0 : = 0         '         '-- scan source bitmap         '         y = 0 sh             sy = y * sstride             x = 0 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)                     p = new point(x, y)                     '                     '-- have pixel match, check region                     '                     y2 = 0 bh - 1                         = y2 * bstride                         x2 = 0 bw - 1                             bx = + 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))                                 '                                 '-- not matching, continue checking                                 '                                 p = nothing                                 sy = y * sstride                                 exit                             end if                          next                         if p = nothing exit                     next                 end if 'end of region check                  if p <> nothing exit             next             if p <> nothing exit         next          bmpbuff = nothing         srcbuff = nothing          return p      end function  end module