Python 差异在';步骤';对于OpenCV中相同图像的两个矩阵
为什么同一图像的两个矩阵的“步长”值不同 其中一个由Python 差异在';步骤';对于OpenCV中相同图像的两个矩阵,python,opencv,Python,Opencv,为什么同一图像的两个矩阵的“步长”值不同 其中一个由LoadImageM()生成,另一个由GetMat()在图像加载LoadImage()后生成。我的代码是: import cv2.cv as cv def main(): org_win = 'Original' cv.NamedWindow(org_win, cv.CV_WINDOW_AUTOSIZE) org_img = cv.LoadImage("bed.jpg", cv.CV_LOAD_IMAGE_COLOR)
LoadImageM()
生成,另一个由GetMat()
在图像加载LoadImage()
后生成。我的代码是:
import cv2.cv as cv
def main():
org_win = 'Original'
cv.NamedWindow(org_win, cv.CV_WINDOW_AUTOSIZE)
org_img = cv.LoadImage("bed.jpg", cv.CV_LOAD_IMAGE_COLOR)
cv.ShowImage(org_win, org_img)
org_img_mat1 = cv.LoadImageM("bed.jpg", cv.CV_LOAD_IMAGE_COLOR)
org_img_mat2 = cv.GetMat(org_img, 0)
print org_img_mat1
print org_img_mat2
cv.WaitKey(0)
cv.DestroyWindow(org_win)
if __name__ == '__main__': main()
我得到的结果是:
<cvmat(type=42424010 8UC3 rows=497 cols=681 step=2043 )>
<cvmat(type=42420010 8UC3 rows=497 cols=681 step=2044 )>
是什么导致阶跃值的差异?请告诉我。这是
cv.LoadImage
和cv.LoadImageM
的源代码:
static PyObject *pycvLoadImage(PyObject *self, PyObject *args, PyObject *kw)
{
const char *keywords[] = { "filename", "iscolor", NULL };
char *filename;
int iscolor = CV_LOAD_IMAGE_COLOR;
if (!PyArg_ParseTupleAndKeywords(args, kw, "s|i", (char**)keywords, &filename, &iscolor))
return NULL;
// Inside ALLOW_THREADS, must not reference 'filename' because it might move.
// So make a local copy 'filename_copy'.
char filename_copy[2048];
strncpy(filename_copy, filename, sizeof(filename_copy));
IplImage *r;
Py_BEGIN_ALLOW_THREADS
r = cvLoadImage(filename_copy, iscolor);
Py_END_ALLOW_THREADS
if (r == NULL) {
PyErr_SetFromErrnoWithFilename(PyExc_IOError, filename);
return NULL;
} else {
return FROM_IplImagePTR(r);
}
}
static PyObject *pycvLoadImageM(PyObject *self, PyObject *args, PyObject *kw)
{
const char *keywords[] = { "filename", "iscolor", NULL };
char *filename;
int iscolor = CV_LOAD_IMAGE_COLOR;
if (!PyArg_ParseTupleAndKeywords(args, kw, "s|i", (char**)keywords, &filename, &iscolor))
return NULL;
// Inside ALLOW_THREADS, must not reference 'filename' because it might move.
// So make a local copy 'filename_copy'.
char filename_copy[2048];
strncpy(filename_copy, filename, sizeof(filename_copy));
CvMat *r;
Py_BEGIN_ALLOW_THREADS
r = cvLoadImageM(filename_copy, iscolor);
Py_END_ALLOW_THREADS
if (r == NULL) {
PyErr_SetFromErrnoWithFilename(PyExc_IOError, filename);
return NULL;
} else {
return FROM_CvMatPTR(r);
}
}
看起来主要的区别是
从IplImagePTR(r)
返回与从CvMatPTR(r)
返回可能步骤
在IplImage
中是基于一个索引的,但在CvMat
中是基于零的索引吗??对于许多其他图像,这两种情况下的步长值相同。然而,几乎所有这些图像都是从相机上获得的标准尺寸,如(1600、1200)、(640、480)等。不太常见的(681497)尺寸可能是造成这种行为的原因,但我没有理由相信。@AbhinavSood有趣。。。当您使用cvCreateImage
或cvCreateMat
时,它会这样做吗?org\u img=cv.LoadImage(“bed.jpg”,cv.cv\u LOAD\u IMAGE\u COLOR)
org\u img\u mat1=cv.LoadImageM(“bed.jpg”,cv.cv\u LOAD\u IMAGE\u COLOR)org\u img\u mat2=cv.GetMat(org\u img,0)print org\u img\u mat1
print org\u img\u mat2
@mevatron不使用CreateImage或CreateMat。