tailieunhanh - Biosignal and Biomedical Image Processing phần 8

Tham khảo tài liệu 'biosignal and biomedical image processing phần 8', kỹ thuật - công nghệ, kĩ thuật viễn thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Fundamentals of Image Processing 285 The specifics can be found in the imwrite help file. The imwrite routine can be used to store any of the data formats or data classes mentioned above however if the data array I is an indexed array then it must be followed by the colormap variable map. Most image formats actually store uint8 formatted data but the necessary conversions are done by the imwrite. The imread function is used to retrieve images from disk. It has the calling structure I map imread fmt or frame where filename is the name of the image file and .ext is any of the extensions listed above. The optional second argument fmt only needs to be specified if the file format is not evident from the filename. The alternative optional argument frame is used to specify which frame of a multiframe image is to be read in I. An example that reads multiframe data is found in Example . As most file formats store images in uint8 format I will often be in that format. File formats .tif and .png support uint16 format so imread may generate data arrays in uint16 format for these file types. The output class depends on the manner in which the data is stored in the file. If the file contains a grayscale image data then the output is encoded as an intensity image if truecolor then as RGB. For both these cases the variable map will be empty which can be checked with the isempty map command see Example . If the file contains indexed data then both output I and map will contain data. The type of data format used by a file can also be obtained by querying a graphics file using the function infinfo. information infinfo where information will contain text providing the essential information about the file including the ColorType FileSize and BitDepth. Alternatively the image data and map can be loaded using imread and the format image data determined from the MATLAB whos command. The whos command will also give the structure of the data variable .