image.h

/*******************************************************
 * Copyright (c) 2014, ArrayFire
 * All rights reserved.
 *
 * This file is distributed under 3-clause BSD license.
 * The complete license agreement can be obtained at:
 * http://arrayfire.com/licenses/BSD-3-Clause
 ********************************************************/

#pragma once
#include <af/defines.h>
#include <af/features.h>

#ifdef __cplusplus
namespace af
{
class array;

/**
   C++ Interface for calculating the gradients

   \param[out] dx the gradient along first dimension
   \param[out] dy the gradient along second dimension
   \param[in] in is the input array

   \ingroup calc_func_grad
*/
AFAPI void grad(array& dx, array& dy, const array& in);

/**
    C++ Interface for loading an image

    \param[in] filename is name of file to be loaded
    \param[in] is_color boolean denoting if the image should be loaded as 1 channel or 3 channel
    \return image loaded as \ref af::array()

    \ingroup imageio_func_load
*/
AFAPI array loadImage(const char* filename, const bool is_color=false);

/**
    C++ Interface for saving an image

    \param[in] filename is name of file to be loaded
    \param[in] in is the arrayfire array to be saved as an image

    \ingroup imageio_func_save
*/
AFAPI void saveImage(const char* filename, const array& in);

#if AF_API_VERSION >= 31
/**
    C++ Interface for loading an image from memory

    \param[in] ptr is the location of the image data in memory. This is the pointer
    created by saveImage.
    \return image loaded as \ref af::array()

    \note The pointer used is a void* cast of the FreeImage type FIMEMORY which is
    created using the FreeImage_OpenMemory API. If the user is opening a FreeImage
    stream external to ArrayFire, that pointer can be passed to this function as well.

    \ingroup imagemem_func_load
*/
AFAPI array loadImageMem(const void *ptr);
#endif

#if AF_API_VERSION >= 31
/**
    C++ Interface for saving an image to memory

    \param[in] in is the arrayfire array to be saved as an image
    \param[in] format is the type of image to create in memory. The enum borrows from
    the FREE_IMAGE_FORMAT enum of FreeImage. Other values not included in imageFormat
    but included in FREE_IMAGE_FORMAT can also be passed to this function.

    \return a void* pointer which is a type cast of the FreeImage type FIMEMORY* pointer.

    \note Ensure that \ref deleteImageMem is called on this pointer. Otherwise there will
    be memory leaks

    \ingroup imagemem_func_save
*/
AFAPI void* saveImageMem(const array& in, const imageFormat format = AF_FIF_PNG);
#endif

#if AF_API_VERSION >= 31
/**
    C++ Interface for deleting memory created by \ref saveImageMem or
    \ref af_save_image_memory

    \param[in] ptr is the pointer to the FreeImage stream created by saveImageMem.

    \ingroup imagemem_func_delete
*/
AFAPI void deleteImageMem(void *ptr);
#endif

#if AF_API_VERSION >= 32
/**
    C++ Interface for loading an image as its original type

    This load image function allows you to load images as u8, u16 or f32
    depending on the type of input image as shown by the table below.

     Bits per Color (Gray/RGB/RGBA Bits Per Pixel) | Array Type  | Range
    -----------------------------------------------|-------------|---------------
      8 ( 8/24/32  BPP)                            | u8          | 0 - 255
     16 (16/48/64  BPP)                            | u16         | 0 - 65535
     32 (32/96/128 BPP)                            | f32         | 0 - 1

    \param[in] filename is name of file to be loaded
    \return image loaded as \ref af::array()

    \ingroup imageio_func_load
*/
AFAPI array loadImageNative(const char* filename);
#endif

#if AF_API_VERSION >= 32
/**
    C++ Interface for saving an image without modifications

    This function only accepts u8, u16, f32 arrays. These arrays are saved to
    images without any modifications.

    You must also note that note all image type support 16 or 32 bit images.

    The best options for 16 bit images are PNG, PPM and TIFF.
    The best option for 32 bit images is TIFF.
    These allow lossless storage.

    The images stored have the following properties:

     Array Type  | Bits per Color (Gray/RGB/RGBA Bits Per Pixel) | Range
    -------------|-----------------------------------------------|---------------
     u8          |  8 ( 8/24/32  BPP)                            | 0 - 255
     u16         | 16 (16/48/64  BPP)                            | 0 - 65535
     f32         | 32 (32/96/128 BPP)                            | 0 - 1

    \param[in] filename is name of file to be saved
    \param[in] in is the array to be saved. Should be u8 for saving 8-bit image,
    u16 for 16-bit image, and f32 for 32-bit image.

    \ingroup imageio_func_save
*/
AFAPI void saveImageNative(const char* filename, const array& in);
#endif

#if AF_API_VERSION >= 33
/**
    Function to check if Image IO is available

    \returns true if ArrayFire was commpiled with ImageIO support, false otherwise.
    \ingroup imageio_func_available
*/
AFAPI bool isImageIOAvailable();
#endif

/**
    C++ Interface for resizing an image to specified dimensions

    \param[in] in is input image
    \param[in] odim0 is the size for the first output dimension
    \param[in] odim1 is the size for the second output dimension
    \param[in] method is the interpolation type (Nearest by default)
    \return the resized image of specified by \p odim0 and \p odim1

    \ingroup transform_func_resize
*/
AFAPI array resize(const array& in, const dim_t odim0, const dim_t odim1, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for resizing an image to specified scales

    \param[in] scale0 is scale used for first input dimension
    \param[in] scale1 is scale used for second input dimension
    \param[in] in is input image
    \param[in] method is the interpolation type (Nearest by default)
    \return the image scaled by the specified by \p scale0 and \p scale1

    \ingroup transform_func_resize
*/
AFAPI array resize(const float scale0, const float scale1, const array& in, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for resizing an image to specified scale

    \param[in] scale is scale used for both input dimensions
    \param[in] in is input image
    \param[in] method is the interpolation type (Nearest by default)
    \return the image scaled by the specified by \p scale

    \ingroup transform_func_resize
*/
AFAPI array resize(const float scale, const array& in, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for rotating an image

    \param[in] in is input image
    \param[in] theta is the degree (in radians) by which the input is rotated
    \param[in] crop if true the output is cropped original dimensions. If false the output dimensions scale based on \p theta
    \param[in] method is the interpolation type (Nearest by default)
    \return the image rotated by \p theta

    \ingroup transform_func_rotate
*/
AFAPI array rotate(const array& in, const float theta, const bool crop=true, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for transforming an image

    \param[in] in is input image
    \param[in] transform is transformation matrix
    \param[in] odim0 is the first output dimension
    \param[in] odim1 is the second output dimension
    \param[in] method is the interpolation type (Nearest by default)
    \param[in] inverse if true applies inverse transform, if false applies forward transoform
    \return the transformed image

    \ingroup transform_func_transform
*/
AFAPI array transform(const array& in, const array& transform, const dim_t odim0 = 0, const dim_t odim1 = 0,
                      const interpType method=AF_INTERP_NEAREST, const bool inverse=true);

#if AF_API_VERSION >= 33
/**
    C++ Interface for transforming coordinates

    \param[in] tf is transformation matrix
    \param[in] d0 is the first input dimension
    \param[in] d1 is the second input dimension
    \return the transformed coordinates

    \ingroup transform_func_coordinates
*/
AFAPI array transformCoordinates(const array& tf, const float d0, const float d1);
#endif

/**
    C++ Interface for translating an image

    \param[in] in is input image
    \param[in] trans0 is amount by which the first dimension is translated
    \param[in] trans1 is amount by which the second dimension is translated
    \param[in] odim0 is the first output dimension
    \param[in] odim1 is the second output dimension
    \param[in] method is the interpolation type (Nearest by default)
    \return the translated image

    \ingroup transform_func_translate
*/
AFAPI array translate(const array& in, const float trans0, const float trans1, const dim_t odim0 = 0, const dim_t odim1 = 0, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for scaling an image

    \param[in] in is input image
    \param[in] scale0 is amount by which the first dimension is scaled
    \param[in] scale1 is amount by which the second dimension is scaled
    \param[in] odim0 is the first output dimension
    \param[in] odim1 is the second output dimension
    \param[in] method is the interpolation type (Nearest by default)
    \return the scaled image

    \ingroup transform_func_scale
*/
AFAPI array scale(const array& in, const float scale0, const float scale1, const dim_t odim0 = 0, const dim_t odim1 = 0, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for skewing an image

    \param[in] in is input image
    \param[in] skew0 is amount by which the first dimension is skewed
    \param[in] skew1 is amount by which the second dimension is skewed
    \param[in] odim0 is the first output dimension
    \param[in] odim1 is the second output dimension
    \param[in] inverse if true applies inverse transform, if false applies forward transoform
    \param[in] method is the interpolation type (Nearest by default)
    \return the skewed image

    \ingroup transform_func_skew
*/
AFAPI array skew(const array& in, const float skew0, const float skew1, const dim_t odim0 = 0, const dim_t odim1 = 0, const bool inverse=true, const interpType method=AF_INTERP_NEAREST);

/**
    C++ Interface for bilateral filter

    \param[in]  in array is the input image
    \param[in]  spatial_sigma is the spatial variance parameter that decides the filter window
    \param[in]  chromatic_sigma is the chromatic variance parameter
    \param[in]  is_color indicates if the input \p in is color image or grayscale
    \return     the processed image

    \ingroup image_func_bilateral
*/
AFAPI array bilateral(const array &in, const float spatial_sigma, const float chromatic_sigma, const bool is_color=false);

/**
   C++ Interface for histogram

   \snippet test/histogram.cpp ex_image_hist_minmax

   \param[in]  in is the input array
   \param[in]  nbins  Number of bins to populate between min and max
   \param[in]  minval minimum bin value (accumulates -inf to min)
   \param[in]  maxval minimum bin value (accumulates max to +inf)
   \return     histogram array of type u32

   \ingroup image_func_histogram
 */
AFAPI array histogram(const array &in, const unsigned nbins, const double minval, const double maxval);

/**
   C++ Interface for histogram

   \snippet test/histogram.cpp ex_image_hist_nominmax

   \param[in]  in is the input array
   \param[in]  nbins  Number of bins to populate between min and max
   \return     histogram array of type u32

   \ingroup image_func_histogram
 */
AFAPI array histogram(const array &in, const unsigned nbins);

/**
    C++ Interface for mean shift

    \param[in]  in array is the input image
    \param[in]  spatial_sigma is the spatial variance parameter that decides the filter window
    \param[in]  chromatic_sigma is the chromatic variance parameter
    \param[in]  iter is the number of iterations filter operation is performed
    \param[in]  is_color indicates if the input \p in is color image or grayscale
    \return     the processed image

    \ingroup image_func_mean_shift
*/
AFAPI array meanShift(const array& in, const float spatial_sigma, const float chromatic_sigma, const unsigned iter, const bool is_color=false);

/**
    C++ Interface for minimum filter

    \param[in]  in array is the input image
    \param[in]  wind_length is the kernel height
    \param[in]  wind_width is the kernel width
    \param[in]  edge_pad value will decide what happens to border when running
                filter in their neighborhood. It takes one of the values [\ref AF_PAD_ZERO | \ref AF_PAD_SYM]
    \return     the processed image

    \ingroup image_func_minfilt
*/
AFAPI array minfilt(const array& in, const dim_t wind_length = 3, const dim_t wind_width = 3, const borderType edge_pad = AF_PAD_ZERO);

/**
    C++ Interface for maximum filter

    \param[in]  in array is the input image
    \param[in]  wind_length is the kernel height
    \param[in]  wind_width is the kernel width
    \param[in]  edge_pad value will decide what happens to border when running
                filter in their neighborhood. It takes one of the values [\ref AF_PAD_ZERO | \ref AF_PAD_SYM]
    \return     the processed image

    \ingroup image_func_maxfilt
*/
AFAPI array maxfilt(const array& in, const dim_t wind_length = 3, const dim_t wind_width = 3, const borderType edge_pad = AF_PAD_ZERO);

/**
    C++ Interface for image dilation (max filter)

    \param[in]  in array is the input image
    \param[in]  mask is the neighborhood window
    \return     the dilated image

    \note if \p mask is all ones, this function behaves like max filter

    \ingroup image_func_dilate
*/
AFAPI array dilate(const array& in, const array& mask);

/**
    C++ Interface for 3D image dilation

    \param[in]  in array is the input volume
    \param[in]  mask is the neighborhood delta volume
    \return     the dilated volume

    \ingroup image_func_dilate3d
*/
AFAPI array dilate3(const array& in, const array& mask);

/**
    C++ Interface for image erosion (min filter)

    \param[in]  in array is the input image
    \param[in]  mask is the neighborhood window
    \return     the eroded image

    \note This function can be used as min filter by using a mask of all ones

    \ingroup image_func_erode
*/
AFAPI array erode(const array& in, const array& mask);

/**
    C++ Interface for 3d for image erosion

    \param[in]  in array is the input volume
    \param[in]  mask is the neighborhood delta volume
    \return     the eroded volume

    \ingroup image_func_erode3d
*/
AFAPI array erode3(const array& in, const array& mask);

/**
    C++ Interface for getting regions in an image

    Below given are sample input and output for each type of connectivity value for \p type

    <table border="0">
    <tr>
    <td> Example for \p type == \ref AF_CONNECTIVITY_8 </td>
    <td> Example for \p type == \ref AF_CONNECTIVITY_4 </td>
    </tr>
    <tr>
    <td>
        \snippet test/regions.cpp ex_image_regions
    </td>
    <td>
        \snippet test/regions.cpp ex_image_regions_4conn
    </td>
    </tr>
    </table>

    \param[in]  in array should be binary image of type \ref b8
    \param[in]  connectivity can take one of the following [\ref AF_CONNECTIVITY_4 | \ref AF_CONNECTIVITY_8]
    \param[in]  type is type of output array
    \return     returns array with labels indicating different regions. Throws exceptions if any issue occur.

    \ingroup image_func_regions
*/
AFAPI array regions(const array& in, const af::connectivity connectivity=AF_CONNECTIVITY_4, const dtype type=f32);

/**
   C++ Interface for extracting sobel gradients

   \param[out] dx is derivative along horizontal direction
   \param[out] dy is derivative along vertical direction
   \param[in]  img is an array with image data
   \param[in]  ker_size sobel kernel size or window size

   \note If \p img is 3d array, a batch operation will be performed.

   \ingroup image_func_sobel
 */
AFAPI void sobel(array &dx, array &dy, const array &img, const unsigned ker_size=3);

/**
   C++ Interface for sobel filtering

   \param[in]  img is an array with image data
   \param[in]  ker_size sobel kernel size or window size
   \param[in]  isFast = true uses \f$G=G_x+G_y\f$, otherwise \f$G=\sqrt (G_x^2+G_y^2)\f$
   \return     an array with sobel gradient values

   \note If \p img is 3d array, a batch operation will be performed.

   \ingroup image_func_sobel
 */
AFAPI array sobel(const array &img, const unsigned ker_size=3, const bool isFast=false);

/**
   C++ Interface for RGB to gray conversion

   \param[in]  in is an array in the RGB colorspace
   \param[in]  rPercent is percentage of red channel value contributing to grayscale intensity
   \param[in]  gPercent is percentage of green channel value contributing to grayscale intensity
   \param[in]  bPercent is percentage of blue channel value contributing to grayscale intensity
   \return     array in Grayscale colorspace

   \note \p in must be three dimensional for RGB to Grayscale conversion.

   \ingroup image_func_rgb2gray
 */
AFAPI array rgb2gray(const array& in, const float rPercent=0.2126f, const float gPercent=0.7152f, const float bPercent=0.0722f);

/**
   C++ Interface for gray to RGB conversion

   \param[in]  in is an array in the Grayscale colorspace
   \param[in]  rFactor is percentage of intensity value contributing to red channel
   \param[in]  gFactor is percentage of intensity value contributing to green channel
   \param[in]  bFactor is percentage of intensity value contributing to blue channel
   \return     array in RGB colorspace

   \note \p in must be two dimensional for Grayscale to RGB conversion.

   \ingroup image_func_gray2rgb
 */
AFAPI array gray2rgb(const array& in, const float rFactor=1.0, const float gFactor=1.0, const float bFactor=1.0);

/**
   C++ Interface for histogram equalization

   \snippet test/histogram.cpp ex_image_histequal

   \param[in]  in is the input array, non-normalized input (!! assumes values [0-255] !!)
   \param[in]  hist target histogram to approximate in output (based on number of bins)
   \return     data with histogram approximately equal to histogram

   \note \p in must be two dimensional.

   \ingroup image_func_histequal
 */
AFAPI array histEqual(const array& in, const array& hist);

/**
   C++ Interface for generating gausian kernels

   \param[in]  rows number of rows of the kernel
   \param[in]  cols number of columns of the kernel
   \param[in]  sig_r (default 0) (calculated internally as 0.25 * rows + 0.75)
   \param[in]  sig_c (default 0) (calculated internally as 0.25 * cols + 0.75)
   \return     an array with values generated using gaussian function

   \ingroup image_func_gauss
 */
AFAPI array gaussianKernel(const int rows, const int cols, const double sig_r = 0, const double sig_c = 0);

/**
   C++ Interface for converting HSV to RGB

   \param[in]  in is an array in the HSV colorspace
   \return     array in RGB colorspace

   \note \p in must be three dimensional

   \ingroup image_func_hsv2rgb
 */
AFAPI array hsv2rgb(const array& in);

/**
   C++ Interface for converting RGB to HSV

   \param[in]  in is an array in the RGB colorspace
   \return     array in HSV colorspace

   \note \p in must be three dimensional

   \ingroup image_func_rgb2hsv
 */
AFAPI array rgb2hsv(const array& in);

/**
   C++ Interface wrapper for colorspace conversion

   \param[in]  image is the input array
   \param[in]  to is the target array colorspace
   \param[in]  from is the input array colorspace
   \return     array in target colorspace

   \note  \p image must be 3 dimensional for \ref AF_HSV to \ref AF_RGB, \ref AF_RGB to
   \ref AF_HSV, & \ref AF_RGB to \ref AF_GRAY transformations. For \ref AF_GRAY to \ref AF_RGB
   transformation, 2D array is expected.

   \ingroup image_func_colorspace
 */
AFAPI array colorSpace(const array& image, const CSpace to, const CSpace from);

#if AF_API_VERSION >= 31
/**
   C++ Interface for rearranging windowed sections of an input into columns
   (or rows)

   \param[in]  in is the input array
   \param[in]  wx is the window size along dimension 0
   \param[in]  wy is the window size along dimension 1
   \param[in]  sx is the stride along dimension 0
   \param[in]  sy is the stride along dimension 1
   \param[in]  px is the padding along dimension 0
   \param[in]  py is the padding along dimension 1
   \param[in]  is_column determines whether the section becomes a column (if
               true) or a row (if false)
   \returns    an array with the input's sections rearraged as columns (or rows)

   \note \p in can hold multiple images for processing if it is three or
         four-dimensional
   \note \p wx and \p wy must be between [1, input.dims(0 (1)) + px (py)]
   \note \p sx and \p sy must be greater than 1
   \note \p px and \p py must be between [0, wx (wy) - 1]. Padding becomes part of
         the input image prior to the windowing

   \ingroup image_func_unwrap
*/
AFAPI array unwrap(const array& in, const dim_t wx, const dim_t wy,
                   const dim_t sx, const dim_t sy, const dim_t px=0, const dim_t py=0,
                   const bool is_column = true);
#endif

#if AF_API_VERSION >= 31
/**
   C++ Interface for performing the opposite of \ref unwrap()

   \param[in]  in is the input array
   \param[in]  ox is the output's dimension 0 size
   \param[in]  oy is the output's dimension 1 size
   \param[in]  wx is the window size along dimension 0
   \param[in]  wy is the window size along dimension 1
   \param[in]  sx is the stride along dimension 0
   \param[in]  sy is the stride along dimension 1
   \param[in]  px is the padding along dimension 0
   \param[in]  py is the padding along dimension 1
   \param[in]  is_column determines whether an output patch is formed from a
               column (if true) or a row (if false)
   \returns    an array with the input's columns (or rows) reshaped as patches

   \note Wrap is typically used to recompose an unwrapped image. If this is the
         case, use the same parameters that were used in \ref unwrap(). Also
         use the original image size (before unwrap) for \p ox and \p oy.
   \note The window/patch size, \p wx \f$\times\f$ \p wy, must equal
         `input.dims(0)` (or `input.dims(1)` if \p is_column is false).
   \note \p sx and \p sy must be at least 1
   \note \p px and \p py must be between [0, wx) and [0, wy), respectively
   \note The number of patches, `input.dims(1)` (or `input.dims(0)` if
         \p is_column is false), must equal \f$nx \times\ ny\f$, where
         \f$\displaystyle nx = \frac{ox + 2px - wx}{sx} + 1\f$ and
         \f$\displaystyle ny = \frac{oy + 2py - wy}{sy} + 1\f$
   \note Batched wrap can be performed on multiple 2D slices at once if \p in
         is three or four-dimensional

   \ingroup image_func_wrap
*/
AFAPI array wrap(const array& in,
                 const dim_t ox, const dim_t oy,
                 const dim_t wx, const dim_t wy,
                 const dim_t sx, const dim_t sy,
                 const dim_t px = 0, const dim_t py = 0,
                 const bool is_column = true);
#endif

#if AF_API_VERSION >= 31
/**
   C++ Interface wrapper for summed area tables

   \param[in]  in is the input array
   \returns the summed area table of input image

   \ingroup image_func_sat
*/
AFAPI array sat(const array& in);
#endif

#if AF_API_VERSION >= 31
/**
   C++ Interface for converting YCbCr to RGB

   \param[in]  in is an array in the YCbCr colorspace
   \param[in]  standard specifies the ITU-R BT "xyz" standard which determines the Kb, Kr values
   used in colorspace conversion equation
   \return     array in RGB colorspace

   \note \p in must be three dimensional and values should lie in the range [0,1]

   \ingroup image_func_ycbcr2rgb
 */
AFAPI array ycbcr2rgb(const array& in, const YCCStd standard=AF_YCC_601);
#endif

#if AF_API_VERSION >= 31
/**
   C++ Interface for converting RGB to YCbCr

   \param[in]  in is an array in the RGB colorspace
   \param[in]  standard specifies the ITU-R BT "xyz" standard which determines the Kb, Kr values
   used in colorspace conversion equation
   \return     array in YCbCr colorspace

   \note \p in must be three dimensional and values should lie in the range [0,1]

   \ingroup image_func_rgb2ycbcr
 */
AFAPI array rgb2ycbcr(const array& in, const YCCStd standard=AF_YCC_601);
#endif

#if AF_API_VERSION >= 34
/**
   C++ Interface for calculating an image moment

   \param[out] out is a pointer to a pre-allocated array where the calculated moment(s) will be placed.
   User is responsible for ensuring enough space to hold all requested moments
   \param[in]  in is the input image
   \param[in] moment is moment(s) to calculate

   \ingroup image_func_moments
 */
AFAPI void moments(double* out, const array& in, const momentType moment=AF_MOMENT_FIRST_ORDER);
#endif

#if AF_API_VERSION >= 34
/**
   C++ Interface for calculating image moments

   \param[in]  in contains the input image(s)
   \param[in] moment is moment(s) to calculate
   \return array containing the requested moment of each image

   \ingroup image_func_moments
 */
AFAPI array moments(const array& in, const momentType moment=AF_MOMENT_FIRST_ORDER);
#endif

#if AF_API_VERSION >= 35
/**
   C++ Interface for canny edge detector

   \param[in] in                  is the input image
   \param[in] thresholdType       determines if user set high threshold is to be used or not. It
                                  can take values defined by the enum \ref af_canny_threshold
   \param[in] lowThresholdRatio   is the lower threshold % of maximum or auto-derived high threshold
   \param[in] highThresholdRatio  is the higher threshold % of maximum value in gradient image used
                                  in hysteresis procedure. This value is ignored if
                                  \ref AF_CANNY_THRESHOLD_AUTO_OTSU is chosen as
                                  \ref af_canny_threshold
   \param[in] sobelWindow     is the window size of sobel kernel for computing gradient direction and
                              magnitude
   \param[in] isFast     indicates if L<SUB>1</SUB> norm(faster but less accurate) is used to compute
                         image gradient magnitude instead of L<SUB>2</SUB> norm.
   \return binary array containing edges

   \ingroup image_func_canny
*/
AFAPI array canny(const array& in, const cannyThreshold thresholdType,
                  const float lowThresholdRatio, const float highThresholdRatio,
                  const unsigned sobelWindow = 3, const bool isFast = false);
#endif

#if AF_API_VERSION >= 36
/**
   C++ Interface for gradient anisotropic(non-linear diffusion) smoothing

   \param[in] in is the input image, expects non-integral (float/double) typed af::array
   \param[in] timestep is the time step used in solving the diffusion equation.
   \param[in] conductance parameter controls the sensitivity of conductance in diffusion equation.
   \param[in] iterations is the number of times the diffusion step is performed.
   \param[in] fftype indicates whether quadratic or exponential flux function is used by algorithm.
    \param[in] diffusionKind will let the user choose what kind of diffusion method to perform. It will take
               any value of enum \ref diffusionEq
   \return A filtered image that is of same size as the input.

   \ingroup image_func_anisotropic_diffusion
*/
AFAPI array anisotropicDiffusion(const af::array& in, const float timestep,
                                 const float conductance, const unsigned iterations,
                                 const fluxFunction fftype=AF_FLUX_EXPONENTIAL,
                                 const diffusionEq diffusionKind=AF_DIFFUSION_GRAD);
#endif

#if AF_API_VERSION >= 37
/**
  C++ Interface for Iterative deconvolution algorithm

  \param[in] in is the blurred input image
  \param[in] ker is the kernel(point spread function) known to have caused
             the blur in the system
  \param[in] iterations is the number of iterations the algorithm will run
  \param[in] relaxFactor is the relaxation factor multiplied with distance
             of estimate from observed image.
  \param[in] algo takes value of type enum \ref af_iterative_deconv_algo
             indicating the iterative deconvolution algorithm to be used
  \return sharp image estimate generated from the blurred input

  \note \p relax_factor argument is ignore when it
  \ref AF_ITERATIVE_DECONV_RICHARDSONLUCY algorithm is used.

  \ingroup image_func_iterative_deconv
 */
AFAPI array iterativeDeconv(const array& in, const array& ker,
                            const unsigned iterations, const float relaxFactor,
                            const iterativeDeconvAlgo algo);

/**
   C++ Interface for Tikhonov deconvolution algorithm

   \param[in] in is the blurred input image
   \param[in] psf is the kernel(point spread function) known to have caused
              the blur in the system
   \param[in] gamma is a user defined regularization constant
   \param[in] algo takes different meaning depending on the algorithm chosen.
              If \p algo is AF_INVERSE_DECONV_TIKHONOV, then \p gamma is
              a user defined regularization constant.
   \return sharp image estimate generated from the blurred input

   \ingroup image_func_inverse_deconv
 */
AFAPI array inverseDeconv(const array& in, const array& psf,
                          const float gamma, const inverseDeconvAlgo algo);
#endif
}
#endif

#ifdef __cplusplus
extern "C" {
#endif

    /**
        C Interface for calculating the gradients

        \param[out] dx the gradient along first dimension
        \param[out] dy the gradient along second dimension
        \param[in]  in is the input array
        \return     \ref AF_SUCCESS if the color transformation is successful,
        otherwise an appropriate error code is returned.

        \ingroup calc_func_grad
    */
    AFAPI af_err af_gradient(af_array *dx, af_array *dy, const af_array in);

    /**
        C Interface for loading an image

        \param[out] out will contain the image
        \param[in] filename is name of file to be loaded
        \param[in] isColor boolean denoting if the image should be loaded as 1 channel or 3 channel
        \return     \ref AF_SUCCESS if the color transformation is successful,
        otherwise an appropriate error code is returned.

        \ingroup imageio_func_load
    */
    AFAPI af_err af_load_image(af_array *out, const char* filename, const bool isColor);

    /**
        C Interface for saving an image

        \param[in] filename is name of file to be loaded
        \param[in] in is the arrayfire array to be saved as an image
        \return     \ref AF_SUCCESS if the color transformation is successful,
        otherwise an appropriate error code is returned.

        \ingroup imageio_func_save
    */
    AFAPI af_err af_save_image(const char* filename, const af_array in);

#if AF_API_VERSION >= 31
    /**
        C Interface for loading an image from memory

        \param[out] out is an array that will contain the image
        \param[in] ptr is the FIMEMORY pointer created by either saveImageMem function, the
        af_save_image_memory function, or the FreeImage_OpenMemory API.
        \return     \ref AF_SUCCESS if successful

        \ingroup imagemem_func_load
    */
    AFAPI af_err af_load_image_memory(af_array *out, const void* ptr);
#endif

#if AF_API_VERSION >= 31
    /**
        C Interface for saving an image to memory using FreeImage

        \param[out] ptr is the FIMEMORY pointer created by FreeImage.
        \param[in] in is the arrayfire array to be saved as an image
        \param[in] format is the type of image to create in memory. The enum borrows from
        the FREE_IMAGE_FORMAT enum of FreeImage. Other values not included in af_image_format
        but included in FREE_IMAGE_FORMAT can also be passed to this function.
        \return     \ref AF_SUCCESS if successful.

        \ingroup imagemem_func_save
    */
    AFAPI af_err af_save_image_memory(void** ptr, const af_array in, const af_image_format format);
#endif

#if AF_API_VERSION >= 31
    /**
        C Interface for deleting an image from memory

        \param[in] ptr is the FIMEMORY pointer created by either saveImageMem function, the
        af_save_image_memory function, or the FreeImage_OpenMemory API.
        \return     \ref AF_SUCCESS if successful

        \ingroup imagemem_func_delete
    */
    AFAPI af_err af_delete_image_memory(void* ptr);
#endif

#if AF_API_VERSION >= 32
    /**
        C Interface for loading an image as is original type

        This load image function allows you to load images as u8, u16 or f32
        depending on the type of input image as shown by the table below.

         Bits per Color (Gray/RGB/RGBA Bits Per Pixel) | Array Type  | Range
        -----------------------------------------------|-------------|---------------
          8 ( 8/24/32  BPP)                            | u8          | 0 - 255
         16 (16/48/64  BPP)                            | u16         | 0 - 65535
         32 (32/96/128 BPP)                            | f32         | 0 - 1

        \param[out] out contains them image
        \param[in] filename is name of file to be loaded
        \return     \ref AF_SUCCESS if successful

        \ingroup imageio_func_load
    */
    AFAPI af_err af_load_image_native(af_array *out, const char* filename);
#endif

#if AF_API_VERSION >= 32
    /**
        C Interface for saving an image without modifications

        This function only accepts u8, u16, f32 arrays. These arrays are saved to
        images without any modifications.

        You must also note that note all image type support 16 or 32 bit images.

        The best options for 16 bit images are PNG, PPM and TIFF.
        The best option for 32 bit images is TIFF.
        These allow lossless storage.

        The images stored have the following properties:

         Array Type  | Bits per Color (Gray/RGB/RGBA Bits Per Pixel) | Range
        -------------|-----------------------------------------------|---------------
         u8          |  8 ( 8/24/32  BPP)                            | 0 - 255
         u16         | 16 (16/48/64  BPP)                            | 0 - 65535
         f32         | 32 (32/96/128 BPP)                            | 0 - 1

        \param[in] filename is name of file to be saved
        \param[in] in is the array to be saved. Should be u8 for saving 8-bit image,
        u16 for 16-bit image, and f32 for 32-bit image.

        \return     \ref AF_SUCCESS if successful

        \ingroup imageio_func_save
    */
    AFAPI af_err af_save_image_native(const char* filename, const af_array in);
#endif

#if AF_API_VERSION >= 33
    /**
        Function to check if Image IO is available

        \param[out] out is true if ArrayFire was commpiled with ImageIO support,
        false otherwise.

        \return     \ref AF_SUCCESS if successful

        \ingroup imageio_func_available
    */
    AFAPI af_err af_is_image_io_available(bool *out);
#endif

    /**
       C Interface for resizing an image to specified dimensions

       \param[out] out will contain the resized image of specified by \p odim0 and \p odim1
       \param[in] in is input image
       \param[in] odim0 is the size for the first output dimension
       \param[in] odim1 is the size for the second output dimension
       \param[in] method is the interpolation type (Nearest by default)

       \return     \ref AF_SUCCESS if the color transformation is successful,
       otherwise an appropriate error code is returned.

       \ingroup transform_func_resize
    */
    AFAPI af_err af_resize(af_array *out, const af_array in, const dim_t odim0, const dim_t odim1, const af_interp_type method);

    /**
       C Interface for transforming an image

       \param[out] out will contain the transformed image
       \param[in] in is input image
       \param[in] transform is transformation matrix
       \param[in] odim0 is the first output dimension
       \param[in] odim1 is the second output dimension
       \param[in] method is the interpolation type (Nearest by default)
       \param[in] inverse if true applies inverse transform, if false applies forward transoform
       \return     \ref AF_SUCCESS if the color transformation is successful,
       otherwise an appropriate error code is returned.

       \ingroup transform_func_transform
    */
    AFAPI af_err af_transform(af_array *out, const af_array in, const af_array transform,
                              const dim_t odim0, const dim_t odim1,
                              const af_interp_type method, const bool inverse);

#if AF_API_VERSION >= 33
    /**
       C Interface for transforming an image
       C++ Interface for transforming coordinates

       \param[out] out the transformed coordinates
       \param[in] tf is transformation matrix
       \param[in] d0 is the first input dimension
       \param[in] d1 is the second input dimension