Some bmp and tif image files cannot be read using the following method, except for the jpeg files. And I want to save it in opencv's Mat structure. What should I do? And I want to convert it into BufferedImage for further processing. I am novice in OpenCV. Recently, I have troubles finding OpenCV functions to convert from Mat to Array. I researched with.ptr and.at methods available in OpenCV. Capture Video from File or Camerabool Video. Capture::read(Mat& image); The function grabs the next frame from the video, decodes it and stores it in the 'image' variable.
The function saves the image in the variable ' img' to a file, specified by 'filename'. If this function fails to save the image, it will return false. On success of writing the file to the harddisk, it will return true. Parameters -. filename - specify the location and name of the file to be saved.
img - hold the image which is going to save. params - This is a int vector to which you have to insert some int parameters specifying the format of the image. JPEG format - You have to puchback CVIMWRITEJPEGQUALITYfirst and then a number between 0 and 100 (higher is the better). If you want the best quality output, use 100. I have used 98 in the above sample program. But higher the value, it will take longer time to write the image. PNG format - You have to puchback CVIMWRITEPNGCOMPRESSION first and then a number between 0 and 9 (higher is the better compression, but slower).
The image format is chosen depending on the file name extension. Only images with 8 bit or 16 bit unsigned single channel or 3 channel ( CV8UC1, CV8UC3, CV8SC1, CV8SC3, CV16UC1, CV16UC3) with ' BGR' channel order, can be saved. If the depth or channel order of the image is different, use 'Mat::convertTo' or 'cvtColor' functions to convert the image to supporting format before using imwritefunction. The above program is very much similar to the program under 'Create a Blank Image & Display' section in the lesson of. If you need further clarifications of any OpenCV functions which are not explained here, please refer to lesson. This program creates an yellowish image ( 3 channels, 16 bit image depth, 650 high, 600 wide, (0, 50,000, 50,000) assigned for BGR channels). Because the image has 16 bit depth, you can use values between 0 and 65535 for each element in each channel. I have used 50,000 for each element in the green and red planes which gives the yellowish color.
You can try different values. Then it specifies the compressing technique. I have used JPEG as the compression technique in the above example.
Then it saves the image in the 'D:/TestImage.jpg' location. Then it displays the newly created image in a window and wait indefinitely until an user presses a key. This is the constructor of the VideoWriter class.
It initializes the object with following parameters. const string& filename - Specify the name and the location of the output file. The video stream is written into this file.
int fourcc - specify the 4 character code for the codec which is used to compress the video. Your computer may not be supported some codecs. So, if you fail to save the video, please try other codecs. Here are some popular codecs.
CVFOURCC('D', 'I', 'V', '3') for DivX MPEG-4 codec. CVFOURCC('M', 'P', '4', '2') for MPEG-4 codec. CVFOURCC('D', 'I', 'V', 'X') for DivX codec. CVFOURCC('P','I','M','1') for MPEG-1 codec. CVFOURCC('I', '2', '6', '3') for ITU H.263 codec. CVFOURCC('M', 'P', 'E', 'G') for MPEG-1 codec Complete list of codec can be found.
double fps - frames per seconds of the video stream. I have used 20. You can try different values. But the codec should support the fps value. So, use an appropriate value. Size frameSize - Size object which specify the width and the height of each frame of the video stream.
bool isColor - If you want to save a color video, pass the value as true. Otherwise false. Remember codec should support whatever value, you pass.
In the above example, you have to give true as the 5th argument. Otherwise it will not work.
CVMATIO An open source Matlab-MAT file parser written in C - CVMATIO implements a Matlab v7 MAT file parser in C, giving users the ability to interact with binary MAT files in their own projects. The project has the following dependencies: OpenCV REQUIRED (for translating Matlab types) CMake REQUIRED (for building) ZLib REQUIRED (for uncompressing Mat files) Doxygen OPTIONAL (for documentation) BUILDING To configure the project, set the options at the top of CMakeLists.txt To build the project, follow the normal cmake routine from the root folder: mkdir build cd build/ cmake.