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41 
42 #ifndef __OPENCV_SEEDS_HPP__
43 #define __OPENCV_SEEDS_HPP__
44 #ifdef __cplusplus
45 
46 #include <opencv2/core.hpp>
47 
48 namespace cv
49 {
50 namespace ximgproc
51 {
52 
53 //! @addtogroup ximgproc_superpixel
54 //! @{
55 
56 /** @brief Class implementing the SEEDS (Superpixels Extracted via Energy-Driven Sampling) superpixels
57 algorithm described in @cite VBRV14 .
58 
59 The algorithm uses an efficient hill-climbing algorithm to optimize the superpixels' energy
60 function that is based on color histograms and a boundary term, which is optional. The energy
61 function encourages superpixels to be of the same color, and if the boundary term is activated, the
62 superpixels have smooth boundaries and are of similar shape. In practice it starts from a regular
63 grid of superpixels and moves the pixels or blocks of pixels at the boundaries to refine the
64 solution. The algorithm runs in real-time using a single CPU.
65  */
66 class CV_EXPORTS_W SuperpixelSEEDS : public Algorithm
67 {
68 public:
69 
70     /** @brief Calculates the superpixel segmentation on a given image stored in SuperpixelSEEDS object.
71 
72     The function computes the superpixels segmentation of an image with the parameters initialized
73     with the function createSuperpixelSEEDS().
74      */
75     CV_WRAP virtual int getNumberOfSuperpixels() = 0;
76 
77     /** @brief Calculates the superpixel segmentation on a given image with the initialized
78     parameters in the SuperpixelSEEDS object.
79 
80     This function can be called again for other images without the need of initializing the
81     algorithm with createSuperpixelSEEDS(). This save the computational cost of allocating memory
82     for all the structures of the algorithm.
83 
84     @param img Input image. Supported formats: CV_8U, CV_16U, CV_32F. Image size & number of
85     channels must match with the initialized image size & channels with the function
86     createSuperpixelSEEDS(). It should be in HSV or Lab color space. Lab is a bit better, but also
87     slower.
88 
89     @param num_iterations Number of pixel level iterations. Higher number improves the result.
90 
91     The function computes the superpixels segmentation of an image with the parameters initialized
92     with the function createSuperpixelSEEDS(). The algorithms starts from a grid of superpixels and
93     then refines the boundaries by proposing updates of blocks of pixels that lie at the boundaries
94     from large to smaller size, finalizing with proposing pixel updates. An illustrative example
95     can be seen below.
96 
97     ![image](pics/superpixels_blocks2.png)
98      */
99     CV_WRAP virtual void iterate(InputArray img, int num_iterations=4) = 0;
100 
101     /** @brief Returns the segmentation labeling of the image.
102 
103     Each label represents a superpixel, and each pixel is assigned to one superpixel label.
104 
105     @param labels_out Return: A CV_32UC1 integer array containing the labels of the superpixel
106     segmentation. The labels are in the range [0, getNumberOfSuperpixels()].
107 
108     The function returns an image with ssthe labels of the superpixel segmentation. The labels are in
109     the range [0, getNumberOfSuperpixels()].
110      */
111     CV_WRAP virtual void getLabels(OutputArray labels_out) = 0;
112 
113     /** @brief Returns the mask of the superpixel segmentation stored in SuperpixelSEEDS object.
114 
115     @param image Return: CV_8UC1 image mask where -1 indicates that the pixel is a superpixel border,
116     and 0 otherwise.
117 
118     @param thick_line If false, the border is only one pixel wide, otherwise all pixels at the border
119     are masked.
120 
121     The function return the boundaries of the superpixel segmentation.
122 
123     @note
124        -   (Python) A demo on how to generate superpixels in images from the webcam can be found at
125             opencv_source_code/samples/python2/seeds.py
126         -   (cpp) A demo on how to generate superpixels in images from the webcam can be found at
127             opencv_source_code/modules/ximgproc/samples/seeds.cpp. By adding a file image as a command
128             line argument, the static image will be used instead of the webcam.
129         -   It will show a window with the video from the webcam with the superpixel boundaries marked
130             in red (see below). Use Space to switch between different output modes. At the top of the
131             window there are 4 sliders, from which the user can change on-the-fly the number of
132             superpixels, the number of block levels, the strength of the boundary prior term to modify
133             the shape, and the number of iterations at pixel level. This is useful to play with the
134             parameters and set them to the user convenience. In the console the frame-rate of the
135             algorithm is indicated.
136 
137     ![image](pics/superpixels_demo.png)
138      */
139     CV_WRAP virtual void getLabelContourMask(OutputArray image, bool thick_line = false) = 0;
140 
~SuperpixelSEEDS()141     virtual ~SuperpixelSEEDS() {}
142 };
143 
144 /** @brief Initializes a SuperpixelSEEDS object.
145 
146 @param image_width Image width.
147 @param image_height Image height.
148 @param image_channels Number of channels of the image.
149 @param num_superpixels Desired number of superpixels. Note that the actual number may be smaller
150 due to restrictions (depending on the image size and num_levels). Use getNumberOfSuperpixels() to
151 get the actual number.
152 @param num_levels Number of block levels. The more levels, the more accurate is the segmentation,
153 but needs more memory and CPU time.
154 @param prior enable 3x3 shape smoothing term if \>0. A larger value leads to smoother shapes. prior
155 must be in the range [0, 5].
156 @param histogram_bins Number of histogram bins.
157 @param double_step If true, iterate each block level twice for higher accuracy.
158 
159 The function initializes a SuperpixelSEEDS object for the input image. It stores the parameters of
160 the image: image_width, image_height and image_channels. It also sets the parameters of the SEEDS
161 superpixel algorithm, which are: num_superpixels, num_levels, use_prior, histogram_bins and
162 double_step.
163 
164 The number of levels in num_levels defines the amount of block levels that the algorithm use in the
165 optimization. The initialization is a grid, in which the superpixels are equally distributed through
166 the width and the height of the image. The larger blocks correspond to the superpixel size, and the
167 levels with smaller blocks are formed by dividing the larger blocks into 2 x 2 blocks of pixels,
168 recursively until the smaller block level. An example of initialization of 4 block levels is
169 illustrated in the following figure.
170 
171 ![image](pics/superpixels_blocks.png)
172  */
173 CV_EXPORTS_W Ptr<SuperpixelSEEDS> createSuperpixelSEEDS(
174     int image_width, int image_height, int image_channels,
175     int num_superpixels, int num_levels, int prior = 2,
176     int histogram_bins=5, bool double_step = false);
177 
178 //! @}
179 
180 }
181 }
182 #endif
183 #endif
184