Image
Toolbox image type

The following public methods are intended for use by application programs:

• Image() : default constructor; builds an empty image.
• Image(const Image&) : copy constructor
• Image(int width, int height, int depth, const char *type, const char *raster) : constructor that creates an image with:
  • dimensions w,h,d ,
  • type type (type is one of "uint8", "uint16", "int32", "binary" ) and
  • if the raster pointer is not NULL, with raster initialized from raster .
• Image(int width, int height, int depth, const char *type = "uint8", double value = 0) : constructor that creates a constant image with size w,h,d , type type and pixels initialized to value
• Image(int pix) : builds an "int32" image 1x1x1 with value pix
• Image(double pix) : builds an "int32" image 1x1x1 with value pix
• Image(const IplImage *img) : builds an image from the OpenCV image pointed by img .
• Image(const char *filename, int iscolor = -1) : reads an image from file filename . The second argument may take the values(see the OpenCV function cvLoadImage ):
  • >0: the loaded image will always have 3 channels (RGB image);
  • =0: the loaded image will always have 1 channel (Grayscale image);
  • <0: the image will be loaded as is.
• ~Image() : destructor
• Image& operator=(const Image&) : assignment operator
• operator IplImage*() const : cast for OpenCV images (creates an OpenCV image from the object image; the caller becomes responsible for the OpenCV image deallocation with cvReleaseImage).
• int width() const : returns the width of the image
• int height() const : returns the height of the image
• int depth() const : returns the depth of the image
• char *raster() const : returns a pointer to the raster of the image (do not free this memory area)
• char ***pointers() const : returns an array of pointers ptr , so that an image pixel can be acessed with ptr[z][y][x]
• String typestr() const : returns the type of the image as a String
• int pixsize() const : returns the size (in bytes) of the image pixel
• String str() const : returns a string representation of the contents of the image suitable for printing small images
• double getpixel(int x, int y, int z) const : returns the value of the pixel at coordinates x,y,z as a double
• void putpixel(int x, int y, int z, double value) : set the value of the pixel at coordinates x,y,z from the double argument value
• void save(char *filename) const : saves the image in filename . The file format is deduced from the filename extension. For supported formats see the OpenCV function cvSaveImage .
• void show(int id = 0, char *title = "OpenCV Viewer") const : raises an OpenCV window and show the image (based on cvShowImage ). The argument id , an integer in range 0-9, chooses one of 10 possible windows.
• Image slice(int x0, int x1, int y0, int y1, int z0, int z1) const : returns an image formed by the subset defined by the arguments: width from x0 to x1, height from y0 to y1 and depth from z0 to z1
• Image uint8() const : returns an uint8 copy of the image
• Image uint16() const : returns an uint16 copy of the image
• Image int32() const : returns an int32 copy of the image
• int isnull() const : returns 1 if this is an empty image
• int isbinary() const : returns 1 if this is a binary image

The class Image is a proxy for the internal toolbox image type. It takes care of chores like memory release and exception catching. When a toolbox function returns an image, an object of this class is created to be returned to the caller. The object constructor catches any error ocurred in the function implementation and, in case of error, throws a morphException .

To free your code of the memory allocation statements, keep your images created in local space, so the underlying C++ system will take care of the memory releasing. Only in the case of returning an image to another procedure, create the image in the heap with the new operator.

See the code of the demonstrations for examples of use of the Image class.