Hello,
Thanks for your reply.
I think the file can be loaded successfully cause I can write it to a local
file after reading it.
Thanks for your advice and I have changed the namespace to OIIO.
My OIIO is downloaded with "brew install opencv”.
I don't know if the oiio downloaded in this way has the header and lib of
opencv.
I'm on a Mac.
I am writing a program and found that only OIIO can read and write EXR and DPX
files perfectly, so I am now reading files from OIIO and then sending them to
CVmat.
Thanks.
My Code updated:
```
#include <OpenImageIO/imagebuf.h>
#include <OpenImageIO/imagebufalgo.h>
#include <OpenImageIO/Imath.h>
#include <OpenImageIO/imagecache.h>
#include <OpenImageIO/imageio.h>
using namespace OIIO;
using namespace cv;
// read
QString img = "./0001.dpx";
ImageBuf buf(img.toStdString());
bool okR = buf.read (0, 0, true, TypeDesc::FLOAT); // true
// write
QString out = "./out.png";
bool okW = buf.write(out.toStdString().data()); // true
// to CV
auto Mat1 = cv::Mat {};
bool succ = ImageBufAlgo::to_OpenCV(Mat1, buf);
// result
qDebug()<< okR << okW << succ; // true true false
```
| |
Juneleung
TD
juneleungc...@163.com
|
---- Replied Message ----
| From | <oiio-dev-requ...@lists.openimageio.org> |
| Date | 05/28/2023 01:18 |
| To | <oiio-dev@lists.openimageio.org> |
| Subject | Oiio-dev Digest, Vol 176, Issue 18 |
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Today's Topics:
1. Connect with opencv (juneleungchan)
2. Re: Connect with opencv (Larry Gritz)
----------------------------------------------------------------------
Message: 1
Date: Sun, 28 May 2023 01:08:38 +0800 (GMT+08:00)
From: juneleungchan <juneleungc...@163.com>
To: "oiio-dev@lists.openimageio.org" <oiio-dev@lists.openimageio.org>
Subject: [Oiio-dev] Connect with opencv
Message-ID: <4c6b78bf.cb38.1885e2f0094.coremail.juneleungc...@163.com>
Content-Type: text/plain; charset="utf-8"
Hello,
Thanks for your great work of OIIO.
I have a question when using OIIO and wanna to ask how to use with details. I'm
not sure if I'm writing to this email address is the right channel to ask
questions. If not, please point me to it, thanks.
My question is about how to convert between OIIO's buf and Opencv. I found
related functions (ImageBufAlgo::to_OpenCV and ImageBufAlgo::from_OpenCV) in
the manual, but it seems that I always get a false result for these the result
of functions .
I would like to ask if I am using it correctly, and is there any sample for
reference?
my code:
```
#include <OpenImageIO/imagebuf.h>
#include <OpenImageIO/imagebufalgo.h>
#include <OpenImageIO/Imath.h>
#include <OpenImageIO/imagecache.h>
#include <OpenImageIO/imageio.h>
using namespace OpenImageIO_v2_4;
using namespace cv;
QString img = ?./0003.png";
ImageBuf buf(img.toStdString());
bool ok = buf.read (0, 0, true, TypeDesc::FLOAT); // true
auto Mat1 = cv::Mat {};
bool succ = ImageBufAlgo::to_OpenCV(Mat1, buf);
qDebug()<< succ ;// false
```
Functions I found:
OpenCV interoperability is performed by the from_OpenCV() and to_OpenCV()
functions:
ImageBuf OIIO::ImageBufAlgo::from_OpenCV(const cv::Mat &mat, TypeDesc convert =
TypeUnknown, ROI roi = {}, int nthreads = 0)
Convert an OpenCV cv::Mat into an ImageBuf, copying the pixels (optionally
converting to the pixel data type specified by convert, if not UNKNOWN, which
means to preserve the original data type if possible). Return true if ok, false
if it couldn?t figure out how to make the conversion from Mat to ImageBuf. If
OpenImageIO was compiled without OpenCV support, this function will return an
empty image with error message set.
bool OIIO::ImageBufAlgo::to_OpenCV(cv::Mat &dst, const ImageBuf &src, ROI roi =
{}, int nthreads = 0)
Construct an OpenCV cv::Mat containing the contents of ImageBuf src, and return
true. If it is not possible, or if OpenImageIO was compiled without OpenCV
support, then return false. Note that OpenCV only supports up to 4 channels, so
>4 channel images will be truncated in the conversion.
Looking forward to your reply and thanks very much.
Juneleung
May 28 2023
| |
Juneleung
TD
juneleungc...@163.com
|
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Message: 2
Date: Sat, 27 May 2023 10:18:04 -0700
From: Larry Gritz <l...@larrygritz.com>
To: OpenImageIO dev list <oiio-dev@lists.openimageio.org>
Subject: Re: [Oiio-dev] Connect with opencv
Message-ID: <87a326c6-7528-4661-bb85-c8fc42c55...@larrygritz.com>
Content-Type: text/plain; charset="utf-8"
I assume that the result of buf.read() is true, so you're sure the image was
read in the first place?
It's only a guess, but it's possible that OpenCV support was not enabled at
build time for OpenImageIO. It needs to find the OpenCV headers and library
when OpenImageIO itself is built, or else the to_OpenCV and from_OpenCV
functions always just return false and don't try to do anything.
I see now that there isn't an especially good way of knowing this from the
built library. I will add something to make it easier to find out (without
being the builder yourself) whether your copy of OIIO has OpenCV support
enabled.
As an unrelated aside, you should change
using namespace OpenImageIO_v2_4;
to
using namespace OIIO;
OIIO is always an alias for the fully versioned namespace. But then you don't
need to update your source code for different versions of OpenImageIO.
On May 27, 2023, at 10:08 AM, juneleungchan <juneleungc...@163.com> wrote:
Hello,
Thanks for your great work of OIIO.
I have a question when using OIIO and wanna to ask how to use with details. I'm
not sure if I'm writing to this email address is the right channel to ask
questions. If not, please point me to it, thanks.
My question is about how to convert between OIIO's buf and Opencv. I found
related functions (ImageBufAlgo::to_OpenCV and ImageBufAlgo::from_OpenCV) in
the manual, but it seems that I always get a false result for these the result
of functions .
I would like to ask if I am using it correctly, and is there any sample for
reference?
my code:
```
#include <OpenImageIO/imagebuf.h>
#include <OpenImageIO/imagebufalgo.h>
#include <OpenImageIO/Imath.h>
#include <OpenImageIO/imagecache.h>
#include <OpenImageIO/imageio.h>
using namespace OpenImageIO_v2_4;
using namespace cv;
QString img = ?./0003.png";
ImageBuf buf(img.toStdString());
bool ok = buf.read (0, 0, true, TypeDesc::FLOAT); // true
auto Mat1 = cv::Mat {};
bool succ = ImageBufAlgo::to_OpenCV(Mat1, buf);
qDebug()<< succ ;// false
```
Functions I found:
OpenCV interoperability is performed by the from_OpenCV() and to_OpenCV()
functions:
ImageBuf OIIO::ImageBufAlgo::from_OpenCV(const cv::Mat &mat, TypeDesc
<https://openimageio.readthedocs.io/en/latest/imageioapi.html#_CPPv4N4OIIO8TypeDescE>
convert = TypeUnknown, ROI
<https://openimageio.readthedocs.io/en/latest/imageioapi.html#_CPPv4N4OIIO3ROIE>
roi = {}, int nthreads = 0)
Convert an OpenCV cv::Mat into an ImageBuf, copying the pixels (optionally
converting to the pixel data type specified by convert, if not UNKNOWN, which
means to preserve the original data type if possible). Return true if ok, false
if it couldn?t figure out how to make the conversion from Mat to ImageBuf. If
OpenImageIO was compiled without OpenCV support, this function will return an
empty image with error message set.
bool OIIO::ImageBufAlgo::to_OpenCV(cv::Mat &dst, const ImageBuf &src, ROI
<https://openimageio.readthedocs.io/en/latest/imageioapi.html#_CPPv4N4OIIO3ROIE>
roi = {}, int nthreads = 0)
Construct an OpenCV cv::Mat containing the contents of ImageBuf src, and return
true. If it is not possible, or if OpenImageIO was compiled without OpenCV
support, then return false. Note that OpenCV only supports up to 4 channels, so
>4 channel images will be truncated in the conversion.
Looking forward to your reply and thanks very much.
Juneleung
May 28 2023
Juneleung
TD
juneleungc...@163.com
<https://dashi.163.com/projects/signature-manager/detail/index.html?ftlId=3&name=Juneleung&uid=juneleungchan%40163.com&iconUrl=https%3A%2F%2Fmail-online.nosdn.127.net%2Fwzpmmc%2F3ef565873cb038cd2c89818903cf0fcc.jpg&email=Juneleungchan%40163.com&position=TD&items=%5B%22Juneleungchan%40163.com%22%5D>
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--
Larry Gritz
l...@larrygritz.com
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