### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [ ] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [ ] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
Usage of imread(): magic number 0, unchecked result
* docs: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* samples, apps: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* tests: rewrite 0/1 to IMREAD_GRAYSCALE/IMREAD_COLOR in imread()
* doc/py_tutorials: check imread() result
Add flags to set the camera intrinsic parameters as an initial guess (can allow converging to the correct camera intrinsic parameters).
Add -imshow-scale flag to resize the image when displaying the results.
Add -enable-k3 flag to enable or disable the estimation of the K3 distortion coefficient.
* add the HH4 mode
* option to display disparity with a color map
* display current settings in the title bar
* don't close app when wanting to take screenshots
* Add a FLANN example showing how to search a query image in a dataset
* Clean: remove warning
* Replace dependency to boost::filesystem by calls to core/utils/filesystem
* Wait for escape key to exit
* Add an example of binary descriptors support
* Add program options for saving and loading the flann structure
* Fix warnings on Win64
* Fix warnings on 3.4 branch still relying on C++03
* Add ctor to img_info structure
* Comments modification
* * Demo file of FLANN moved and renamed
* Fix distances type when using binary vectors in the FLANN example
* Rename FLANN example file
* Remove dependency of the flann example to opencv_contrib's SURF.
* Remove mention of FLANN and other descriptors that aimed at giving hint on the other options
* Cleaner program options management
* Make waitKey usage minimal in FLANN example
* Fix the conditions order
* Use cv::Ptr
* Implement ASIFT in C++
* '>>' should be '> >' within a nested template
* add a sample for asift usage
* bugfix empty keypoints cause crash
* simpler initialization for mask
* suppress the number of lines
* correct tex document
* type casting
* add descriptorsize for asift
* smaller testdata for asift
* more smaller test data
* add OpenCV short license header
I believe you are using the wrong version of open() on line 28 - adding deviceID + appId together. It's better to use the new version of .open() taking two integers as parameter.
