數(shù)字圖像處理- 幾何變換

1、配套課件數(shù)字圖像處理 編程框架、理論分析、實(shí)例應(yīng)用和源碼實(shí)現(xiàn)數(shù)字圖像處理1幾何變換，就是一個像素的值保持不變，但它的位置發(fā)生改變，并且這種改變符合一定的幾何數(shù)學(xué)特性。不同的幾何數(shù)學(xué)特性，就決定了幾何變換的類型，例如簡單的幾何變換包括平移、旋轉(zhuǎn)、鏡像、轉(zhuǎn)置、縮放和切變，而復(fù)雜的幾何變換包括仿射變換、投影變換和非剛體變換。數(shù)字圖像處理2數(shù)字圖像處理3數(shù)字圖像處理4平移旋轉(zhuǎn)鏡像轉(zhuǎn)置切變縮放數(shù)字圖像處理5xy0s(x,y)t(x,y)(xs,ys)(xt,yt)dxdy向前映射向后映射數(shù)字圖像處理6數(shù)字圖像處理7CTMatrix CImageProcessing:Image_translation(

2、const CTMatrix& color_image, long delta_x, long delta_y )long image_height = color_image.Get_height();long image_width = color_image.Get_width();long new_height = image_height + abs( delta_y );long new_width = image_width + abs( delta_x );CTMatrix translated_image( new_height, new_width );for( i

3、nt row = 0; row new_height; row + )for( int column = 0; column 0 )row_mapped = row - delta_y;int column_mapped = column;if( delta_x 0 )column_mapped = column - delta_x;if( color_image.Is_point_valid( CImagePoint( row_mapped, column_mapped ) ) )translated_image row column = color_image row_mapped col

4、umn_mapped ;elsetranslated_image row column = RGB_TRIPLE( 128, 128, 128 );return translated_image;數(shù)字圖像處理8void CDigitalImageProcessingDoc:OnGeometrytransformImagetranslation()/ TODO: Add your command handler code hereif( m_image.IsColorImage()long delta_x = 60;long delta_y = 30;CTMatrix translated_im

5、age = CImageProcessing:Image_translation( m_image.Get_color_image(), delta_x, delta_y );m_image.ImportFrom( translated_image );UpdateAllViews(NULL);數(shù)字圖像處理9向前映射向后映射數(shù)字圖像處理10數(shù)字圖像處理11xy0s(x,y)t(x,y)(xs,ys)(xt,yt)數(shù)字圖像處理12數(shù)字圖像處理13向前映射向后映射數(shù)字圖像處理14數(shù)字圖像處理15CTMatrix CImageProcessing:Image_mirror( const CTMatr

6、ix& color_image, bool is_horizontal )long image_height = color_image.Get_height();long image_width = color_image.Get_width();CTMatrix dest_image( image_height, image_width );for( long row = 0; row image_height; row + )for( long column = 0; column image_width; column + )long source_row = row;long

7、 source_column = column;if( is_horizontal = true )source_column = image_width - column - 1;elsesource_row = image_height - row - 1;dest_image row column = color_image source_row source_column ;return dest_image;數(shù)字圖像處理16數(shù)字圖像處理17數(shù)字圖像處理18CTMatrix CImageProcessing:Image_transpose( const CTMatrix& co

8、lor_image )long image_height = color_image.Get_height();long image_width = color_image.Get_width();CTMatrix dest_image( image_width, image_height );for( long row = 0; row image_width; row + )for( long column = 0; column image_height; column + )long source_row = column;long source_column = row;dest_i

9、mage row column = color_image source_row source_column ;return dest_image;數(shù)字圖像處理19逆時針旋轉(zhuǎn)90度垂直鏡像旋轉(zhuǎn)轉(zhuǎn)置數(shù)字圖像處理20 xy0s(x,y)t(x,y)(xs,ys)(xt,yt)HsHtWsWtSV=Ht/HsSH=Wt/Ws向前映射向后映射數(shù)字圖像處理21數(shù)字圖像處理22CTMatrix CImageProcessing:Image_zoom( const CTMatrix& color_image, double horizontal_scale, double vertical_scal

10、e )long source_height = color_image.Get_height();long source_width = color_image.Get_width();long dest_height = long( source_height * vertical_scale );long dest_width = long( source_width * horizontal_scale );CTMatrix dest_image( dest_height, dest_width );for( int dest_row = 0; dest_row dest_height;

11、 dest_row + )for( int dest_column = 0; dest_column dest_width; dest_column + )long source_row = long( dest_row / vertical_scale );long source_column = long( dest_column / horizontal_scale );if( color_image.Is_point_valid( CImagePoint( source_row, source_column ) ) )dest_image dest_row dest_column =

12、color_image source_row source_column ;elsedest_image dest_row dest_column = RGB_TRIPLE( 128, 128, 128 );return dest_image;數(shù)字圖像處理23切變，是一種坐標(biāo)系的扭曲變換，進(jìn)行非均勻的拉伸。切變的時候，角度會發(fā)生變化，但面積卻保持不變。數(shù)字圖像處理24xy0s(x,y)t(x,y)(xs,ys)(xt,yt)HsHtWsWtHt=Hs+s2WsWt=Ws+s1Hs向前映射向后映射數(shù)字圖像處理25數(shù)字圖像處理26仿射變換投影變換非剛體變換數(shù)字圖像處理27平移變換圖像旋轉(zhuǎn)圖像縮放仿

13、射變換，是一種二維坐標(biāo)到二維坐標(biāo)之間的線性變換，保持二維圖形的“平直性”（即變換后直線還是直線，不會打彎，圓弧還是圓弧）和“平行性”（即保證二維圖形間的相對位置關(guān)系不變，平行線還是平行線，相交直線之間的夾角不變）仿射變換可以理解為：1）對坐標(biāo)進(jìn)行縮放、旋轉(zhuǎn)和平移后取得的新坐標(biāo)值；2）經(jīng)過對坐標(biāo)軸的縮放、旋轉(zhuǎn)和平移后原坐標(biāo)在新坐標(biāo)系中的值。數(shù)字圖像處理28數(shù)字圖像處理29數(shù)字圖像處理30CTMatrix CImageProcessing:Image_affine( const CTMatrix& color_image, double m00, double m01, double m0

14、2, double m10, double m11, double m12 )long source_height = color_image.Get_height();long source_width = color_image.Get_width();long dest_height = source_height * 2;long dest_width = source_width * 2;CTMatrix dest_image( dest_height, dest_width );for( int dest_row = 0; dest_row dest_height; dest_ro

15、w + )for( int dest_column = 0; dest_column dest_width; dest_column + )int source_column = int( m00 * dest_column + m01 * dest_row + m02 );int source_row = int( m10 * dest_column + m11 * dest_row + m12 );if( color_image.Is_point_valid( CImagePoint( source_row, source_column ) ) )dest_image dest_row dest_column = color_image source_row source_column ;elsedest_image dest_row dest_column = RGB_TRIPLE( 128, 128, 128