cvFloodFill的使用方法和注意事項。


#include "stdafx.h"
#include "cv.h"
#include "highgui.h"
#include <stdio.h>
#include <stdlib.h>

IplImage* color_img0;
IplImage* mask;
IplImage* color_img;
IplImage* gray_img0 = NULL;
IplImage* gray_img = NULL;
int ffill_case = 1;
int lo_diff = 20, up_diff = 20;
int connectivity = 4;
int is_color = 1;
int is_mask = 0;
int new_mask_val = 255;

void on_mouse( int event, int x, int y, int flags, void* param )
{
    if( !color_img )
        return;

    switch( event )
    {
    case CV_EVENT_LBUTTONDOWN:
        {
            CvPoint seed = cvPoint(x,y);
            int lo = ffill_case == 0 ? 0 : lo_diff;
            int up = ffill_case == 0 ? 0 : up_diff;
            int flags = connectivity + (new_mask_val << 8) +
                        (ffill_case == 1 ? CV_FLOODFILL_FIXED_RANGE : 0);
            int b = rand() & 255, g = rand() & 255, r = rand() & 255;//隨機找到一個顏色
            CvConnectedComp comp;

            if( is_mask )
                cvThreshold( mask, mask, 1, 128, CV_THRESH_BINARY );
           
            if( is_color )
            {
                CvScalar color = CV_RGB( r, g, b );
                cvFloodFill( color_img, seed, color, CV_RGB( lo, lo, lo ),
                             CV_RGB( up, up, up ), &comp, flags, is_mask ? mask : NULL );//從點擊的位置把連接到的範圍用上面隨機顏色填充
                cvShowImage( "image", color_img );
            }
            else
            {
                CvScalar brightness = cvRealScalar((r*2 + g*7 + b + 5)/10);
                cvFloodFill( gray_img, seed, brightness, cvRealScalar(lo),
                             cvRealScalar(up), &comp, flags, is_mask ? mask : NULL );
                cvShowImage( "image", gray_img );
            }

            printf("%g pixels were repainted/n", comp.area );

            if( is_mask )
                cvShowImage( "mask", mask );
        }
        break;
    }
}

int main( int argc, char** argv )
{
    char* filename = argc >= 2 ? argv[1] : (char*)"fruits.jpg";

    if( (color_img0 = cvLoadImage(filename,1)) == 0 )
        return 0;

    printf( "Hot keys: /n"
            "/tESC - quit the program/n"
            "/tc - switch color/grayscale mode/n"
            "/tm - switch mask mode/n"
            "/tr - restore the original image/n"
            "/ts - use null-range floodfill/n"
            "/tf - use gradient floodfill with fixed(absolute) range/n"
            "/tg - use gradient floodfill with floating(relative) range/n"
            "/t4 - use 4-connectivity mode/n"
            "/t8 - use 8-connectivity mode/n" );
       
    color_img = cvCloneImage( color_img0 );
    gray_img0 = cvCreateImage( cvSize(color_img->width, color_img->height), 8, 1 );
    cvCvtColor( color_img, gray_img0, CV_BGR2GRAY );
    gray_img = cvCloneImage( gray_img0 );
    mask = cvCreateImage( cvSize(color_img->width + 2, color_img->height + 2), 8, 1 );

    cvNamedWindow( "image", 0 );
    cvCreateTrackbar( "lo_diff", "image", &lo_diff, 255, NULL );
    cvCreateTrackbar( "up_diff", "image", &up_diff, 255, NULL );

    cvSetMouseCallback( "image", on_mouse, 0 );

    for(;;)
    {
        int c;
       
        if( is_color )
            cvShowImage( "image", color_img );
        else
            cvShowImage( "image", gray_img );

        c = cvWaitKey(0);
        switch( (char) c )
        {
        case '/x1b':
            printf("Exiting .../n");
            goto exit_main;
        case 'c':
            if( is_color )
            {
                printf("Grayscale mode is set/n");
                cvCvtColor( color_img, gray_img, CV_BGR2GRAY );
                is_color = 0;
            }
            else
            {
                printf("Color mode is set/n");
                cvCopy( color_img0, color_img, NULL );
                cvZero( mask );
                is_color = 1;
            }
            break;
        case 'm':
            if( is_mask )
            {
                cvDestroyWindow( "mask" );
                is_mask = 0;
            }
            else
            {
                cvNamedWindow( "mask", 0 );
                cvZero( mask );
                cvShowImage( "mask", mask );
                is_mask = 1;
            }
            break;
        case 'r':
            printf("Original image is restored/n");
            cvCopy( color_img0, color_img, NULL );
            cvCopy( gray_img0, gray_img, NULL );
            cvZero( mask );
            break;
        case 's':
            printf("Simple floodfill mode is set/n");
            ffill_case = 0;
            break;
        case 'f':
            printf("Fixed Range floodfill mode is set/n");
            ffill_case = 1;
            break;
        case 'g':
            printf("Gradient (floating range) floodfill mode is set/n");
            ffill_case = 2;
            break;
        case '4':
            printf("4-connectivity mode is set/n");
            connectivity = 4;
            break;
        case '8':
            printf("8-connectivity mode is set/n");
            connectivity = 8;
            break;
        }
    }

exit_main:

    cvDestroyWindow( "test" );
    cvReleaseImage( &gray_img );
    cvReleaseImage( &gray_img0 );
    cvReleaseImage( &color_img );
    cvReleaseImage( &color_img0 );
    cvReleaseImage( &mask );

    return 1;
}
//問題在這,當你用鼠標一直點擊一個點時,你會發現連接範圍越來越大;因爲它會把這個地方填充你隨機的顏色,當下次點擊時候而這個顏色又會和其他區域連同,使得區域越來越大!
FloodFill
用指定顏色填充一個連接域

void cvFloodFill( CvArr* image, CvPoint seed_point, CvScalar new_val,
CvScalar lo_diff=cvScalarAll(0), CvScalar up_diff=cvScalarAll(0),
CvConnectedComp* comp=NULL, int flags=4, CvArr* mask=NULL );
#define CV_FLOODFILL_FIXED_RANGE (1 << 16)
#define CV_FLOODFILL_MASK_ONLY (1 << 17)
image
輸入的 1- 或 3-通道, 8-比特或浮點數圖像。輸入的圖像將被函數的操作所改變,除非你選擇 CV_FLOODFILL_MASK_ONLY 選項 (見下面).
seed_point
開始的種子點.
new_val
新的重新繪製的象素值
lo_diff
當前觀察象素值與其部件領域象素或者待加入該部件的種子象素之負差(Lower difference)的最大值。對 8-比特 彩色圖像,它是一個 packed value.
up_diff
當前觀察象素值與其部件領域象素或者待加入該部件的種子象素之正差(upper difference)的最大值。 對 8-比特 彩色圖像,它是一個 packed value.
comp
指向部件結構體的指針,該結構體的內容由函數用重繪區域的信息填充。
flags
操作選項. 低位比特包含連通值, 4 (缺省) 或 8, 在函數執行連通過程中確定使用哪種鄰域方式。高位比特可以是 0 或下面的開關選項的組合:
CV_FLOODFILL_FIXED_RANGE - 如果設置,則考慮當前象素與種子象素之間的差,否則考慮當前象素與其相鄰象素的差。(範圍是浮點數).
CV_FLOODFILL_MASK_ONLY - 如果設置,函數不填充原始圖像 (忽略 new_val), 但填充掩模圖像 (這種情況下 MASK 必須是非空的).
mask
運算掩模, 應該是單通道、8-比特圖像, 長和寬上都比輸入圖像 image 大兩個象素點。若非空,則函數使用且更新掩模, 所以使用者需對 mask 內容的初始化負責。填充不會經過 MASK 的非零象素, 例如,一個邊緣檢測子的輸出可以用來作爲 MASK 來阻止填充邊緣。或者有可能在多次的函數調用中使用同一個 MASK,以保證填充的區域不會重疊。注意: 因爲 MASK 比欲填充圖像大,所以 mask 中與輸入圖像(x,y)像素點相對應的點具有(x+1,y+1)座標。
函數 cvFloodFill 用指定顏色,從種子點開始填充一個連通域。連通性由象素值的接近程度來衡量

但好像cvFloodFill並沒有定義連通性,就像ps中的魔棒,可以選取的區域不同!

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