我正在做 Bradski 的“Learning OpenCV”的示例 11-1。我的实现在尝试使用 cvInitUndistortMap() 时崩溃。
一个类似的帖子（这里）有关于 cvUndistort2() 和 cvRemap() 使用彩色图像的问题。我不确定这里的问题是否相关。
代码如下：
#include "stdafx.h"
#include "opencv\cv.h"
#include "opencv\highgui.h"
#include "stdio.h"
#include "stdlib.h"
#include "iostream"
#include "iomanip"
using namespace std;
int n_boards;
const int board_dt = 20; // Wait 20 frames per chessboard view
int board_w;
int board_h;
int main(int argc, char* argv[])
{
board_w = 7;
board_h = 7;
n_boards = 10;
int board_n = board_w * board_h;
CvSize board_sz = cvSize(board_w, board_h);
CvCapture* capture = cvCreateCameraCapture(0);
assert(capture);
cvNamedWindow("Calibration");
// Allocate storage
CvMat* image_points = cvCreateMat(n_boards*board_n,2,CV_32FC1);
CvMat* object_points = cvCreateMat(n_boards*board_n,3,CV_32FC1);
CvMat* point_counts = cvCreateMat(n_boards,1,CV_32SC1);
CvMat* intrinsic_matrix = cvCreateMat(3,3,CV_32FC1);
CvMat* distortion_coeffs = cvCreateMat(5,1,CV_32FC1);
CvPoint2D32f* corners = new CvPoint2D32f[ board_n ];
int corner_count;
int successes = 0;
int step, frame = 0;
IplImage *image = cvQueryFrame(capture);
IplImage *gray_image = cvCreateImage(cvGetSize(image),8,1); // subpixel
// Capture corner views loop until we've got n_boards
// Successful captures (all corners on the board are found)
//
while(successes < n_boards) {
// Skip every board_dt frames to allow user to move chessboard
if(frame++ % board_dt == 0){
//Find chessboard corners:
int found = cvFindChessboardCorners(
image, board_sz, corners, &corner_count,
CV_CALIB_CB_ADAPTIVE_THRESH | CV_CALIB_CB_FILTER_QUADS
);
// Get subpixel accuracy on those corners
cvCvtColor(image, gray_image, CV_BGR2GRAY);
cvFindCornerSubPix(gray_image, corners, corner_count,
cvSize(11,11),cvSize(-1,-1), cvTermCriteria(
CV_TERMCRIT_EPS+CV_TERMCRIT_ITER,30,0.1));
// Draw it
cvDrawChessboardCorners(image, board_sz, corners, corner_count, found);
cvShowImage("Calibration", image);
// If we got a good board, add it to our data
if(corner_count == board_n){
step = successes*board_n;
for( int i=step, j=0; j<board_n; ++i,++j){
CV_MAT_ELEM(*image_points, float, i, 0) = corners[j].x;
CV_MAT_ELEM(*image_points, float, i, 1) = corners[j].y;
CV_MAT_ELEM(*object_points, float, i, 0) = j/board_w;
CV_MAT_ELEM(*object_points, float, i, 1) = j%board_w;
CV_MAT_ELEM(*object_points, float, i, 2) = 0.0f;
}
CV_MAT_ELEM(*point_counts, int, successes, 0) = board_n;
successes++;
}
//display how many successes we currently have
printf("\nImages: %d / %d", successes, n_boards);
} // end skip board_dt between chessboard capture
// Handle pause/unpause and ESC
int c = cvWaitKey(15);
if(c=='p'){
c = 0;
while(c!='p' && c != 27){
c = cvWaitKey(250);
}
}
if(c==27)
return 0;
image = cvQueryFrame(capture); // get next image
} // end collection while loop
// Allocate matrices according to how many chessboards were found
printf("\n\n\nAllocating matrices...");
CvMat* object_points2 = cvCreateMat(successes*board_n,3,CV_32FC1);
CvMat* image_points2 = cvCreateMat(successes*board_n,2,CV_32FC1);
CvMat* point_counts2 = cvCreateMat(successes,1,CV_32SC1);
printf("success!");
// Transfer the points into the correct size matrices
/*
printf("\nTransfering points into the correct size matrices...");
image_points->rows = object_points->rows = \
successes*board_n;
point_counts->rows = successes;
printf("success!");
*/
// The above two lines can alternatively be written in the following two loops
printf("\nTransfering points into the correct size matrices...");
for(int i=0; i<successes*board_n; ++i){
CV_MAT_ELEM(*image_points2, float, i, 0) = CV_MAT_ELEM(*image_points, float, i, 0);
CV_MAT_ELEM(*image_points2, float, i, 1) = CV_MAT_ELEM(*image_points, float, i, 1);
CV_MAT_ELEM(*object_points2, float, i, 0) = CV_MAT_ELEM(*object_points, float, i, 0);
CV_MAT_ELEM(*object_points2, float, i, 1) = CV_MAT_ELEM(*object_points, float, i, 1);
CV_MAT_ELEM(*object_points2, float, i, 2) = CV_MAT_ELEM(*object_points, float, i, 2);
}
for(int i=0; i<successes; ++i){ //These are all the same number
CV_MAT_ELEM(*point_counts2, int, i, 0) = CV_MAT_ELEM(*point_counts, int, i, 0);
}
printf("success!");
// At this point, we have all the chessboard corners we need.
// Initialize the intrinsic matrix such that the two focal lengths
// have a ratio of 1.0
//
printf("\nInitializing intrinsic matrix...");
CV_MAT_ELEM(*intrinsic_matrix, float, 0, 0) = 1.0f;
CV_MAT_ELEM(*intrinsic_matrix, float, 1, 1) = 1.0f;
printf("success!");
// Calibrate the camera
printf("\nCalibrating camera...");
cvCalibrateCamera2(
object_points2, image_points2,
point_counts2, cvGetSize(image),
intrinsic_matrix, distortion_coeffs,
NULL, NULL, 0 //CV_CALIB_FIX_ASPECT_RATIO
);
printf("success!");
// Save the intrinsics and distortions
printf("\nSaving intrinsic matrix and distortion coefficients...");
cvSave("Instrinsics.xml",intrinsic_matrix);
cvSave("Distortion.xml",distortion_coeffs);
printf("success!");
// Release old objects
printf("\nReleasing old objects...");
cvReleaseMat(&object_points);
cvReleaseMat(&image_points);
cvReleaseMat(&point_counts);
cvReleaseMat(&object_points2);
cvReleaseMat(&image_points2);
cvReleaseMat(&point_counts2);
cvReleaseMat(&intrinsic_matrix);
cvReleaseMat(&distortion_coeffs);
printf("success!");
// Example of loading the above matrices back in
printf("\nLoading intrinsic matrix and distortion coefficients...");
CvMat *intrinsic = (CvMat*)cvLoad("Intrinsics.xml");
CvMat *distortion = (CvMat*)cvLoad("Distortion.xml");
printf("success!");
// Build the undistort map that we will use for all subsequent frames
printf("\nBuilding undistort map...");
IplImage* mapx = cvCreateImage( cvGetSize(image), IPL_DEPTH_32F, 1);
IplImage* mapy = cvCreateImage( cvGetSize(image), IPL_DEPTH_32F, 1);
printf("\nCrash incoming...");
cvInitUndistortMap( // PROBLEM APPEARS TO BE HERE
intrinsic,
distortion,
mapx,
mapy
);
printf("success!");
// Just run the camera to the screen, now showing the raw
// and the undistorted image.
printf("Displaying undistorted images...");
cvNamedWindow("Undistort");
while(image) {
IplImage *image = cvQueryFrame(capture);
IplImage *imageRemapped = cvCloneImage(image);
cvShowImage("Calibration", image); // Show raw image
cvRemap(image, imageRemapped, mapx, mapy); // Undistort image
cvShowImage("Undistort", imageRemapped); // Show corrected image
// Handle pause/unpause and ESC
int c = cvWaitKey(15);
if(c=='p'){
c=0;
while(c!='p' && c!=27){
c = cvWaitKey(250);
}
}
if(c==27){
cvReleaseImage(&image);
cvReleaseImage(&imageRemapped);
break;}
image = cvQueryFrame(capture);
}
printf("success!");
return 0;
}
其中 Intrinsics.xml 和 Distortion.xml 的校准结果如下：
Intrinsics.xml：
<?xml version="1.0"?>
<opencv_storage>
<Instrinsics type_id="opencv-matrix">
<rows>3</rows>
<cols>3</cols>
<dt>f</dt>
<data>
6.58263672e+002 0. 3.61270020e+002 0. 6.50179993e+002
2.34282578e+002 0. 0. 1.</data></Instrinsics>
</opencv_storage>
失真.xml：
<?xml version="1.0"?>
<opencv_storage>
<Distortion type_id="opencv-matrix">
<rows>5</rows>
<cols>1</cols>
<dt>f</dt>
<data>
-1.43585190e-001 1.10129333e+000 -3.21008405e-003 2.23791786e-002
-3.69336128e+000</data></Distortion>
</opencv_storage>
我正在使用 OpenCV 2.4、Windows7、Microsoft Visual C++ 2010 Express 和 MBP 网络摄像头。