該例程講述瞭如何通過網格圖來矯正一個曲面
* This example illustrates how to use the operators for the grid-rectification.
*
* The following command creates a postscript file
* that contains the rectification grid. This grid must be
* printed. Then it must be mounted on the object surface.
WidthOfGrid := 0.17
NumSquares := 17
// 創建一個矯正網絡
create_rectification_grid (WidthOfGrid, NumSquares, 'rectification_grid.ps')
*
* Read the image of the object wrapped by the rectification grid
* and reopen the window with an appropriate size.
read_image (Image, 'can_with_grid')
get_image_size (Image, ImageWidth, ImageHeight)
dev_close_window ()
dev_open_window (0, 0, ImageWidth * 0.75, ImageHeight * 0.75, 'black', WindowID1)
dev_display (Image)
dev_update_off ()
set_display_font (WindowID1, 14, 'mono', 'true', 'false')
*
*
* Part 1: Determination of the image map
* The surface to be rectified is wrapped by a checkered pattern, which
* is used to determine the mapping between the distorted image and
* the rectified image. Note the orientation of the two circular marks. When
* in gen_grid_rectification_map() the parameter Rotation is 'auto', the rectified
* image is rotated such that the black mark is left of the white mark.
*
* Determine region of interest
MinContrast := 25
Radius := 10
// 定位到需要矯正的網格區域
find_rectification_grid (Image, GridRegion, MinContrast, Radius)
*
dev_display (GridRegion)
disp_message (WindowID1, 'Grid region', 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID1, 'black', 'true')
stop ()
reduce_domain (Image, GridRegion, ImageReduced)
*
* Determine grid points
SigmaSaddlePoints := 1.5
Threshold := 5
// 檢測一副圖像中的亞像素鞍點，輸出定位到的點的座標
saddle_points_sub_pix (ImageReduced, 'facet', SigmaSaddlePoints, Threshold, Row, Col)
*
dev_set_color ('blue')
gen_cross_contour_xld (SaddlePoints, Row, Col, 6, 0.785398)
dev_display (Image)
dev_display (SaddlePoints)
disp_message (WindowID1, 'Grid points', 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID1, 'black', 'true')
stop ()
*
* Connect points to grid
SigmaConnectGridPoints := 0.9
MaxDist := 5.0
GridSpacing := 20
dev_set_color ('red')
// 把矯正過後的網格點連接成線
connect_grid_points (ImageReduced, ConnectingLines, Row, Col, SigmaConnectGridPoints, MaxDist)
*
dev_display (ConnectingLines)
disp_message (WindowID1, 'Connected grid points', 'window', 12, 12, 'black', 'true')
disp_continue_message (WindowID1, 'black', 'true')
stop ()
*
* Determine image map
// 生成映射關係
gen_grid_rectification_map (ImageReduced, ConnectingLines, Map, Meshes, GridSpacing, 0, Row, Col, 'bilinear')
map_image (ImageReduced, Map, ImageMapped)
*
get_image_size (Map, MapWidth, MapHeight)
dev_open_window (0, (ImageWidth * 0.75) + 12, MapWidth, MapHeight, 'black', WindowID2)
set_display_font (WindowID2, 14, 'mono', 'true', 'false')
dev_display (ImageMapped)
disp_message (WindowID2, 'Rectified grid', 'window', 12, 12, 'black', 'true')
stop ()
*
*
* Part 2: Application of the image map
* The original surface (without the checkered pattern) is rectified
* using the previously calculated image map.
*
* Read in the image to be rectified
read_image (Image, 'can')
*
* Rectify image using the previously calculated image map
dev_set_window (WindowID2)
map_image (Image, Map, ImageMapped)
*
dev_set_window (WindowID1)
dev_display (Image)
disp_message (WindowID1, 'Original image', 'window', 12, 12, 'black', 'true')
dev_set_window (WindowID2)
dev_display (ImageMapped)
disp_message (WindowID2, 'Rectified image', 'window', 12, 12, 'black', 'true')
圖1 矯正前
圖2：矯正後