Class Imgcodecs

java.lang.Object
org.opencv.imgcodecs.Imgcodecs

public class Imgcodecs extends Object
  • Field Details

    • IMREAD_UNCHANGED

      public static final int IMREAD_UNCHANGED
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    • IMREAD_GRAYSCALE

      public static final int IMREAD_GRAYSCALE
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    • IMREAD_COLOR

      public static final int IMREAD_COLOR
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    • IMREAD_ANYDEPTH

      public static final int IMREAD_ANYDEPTH
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    • IMREAD_ANYCOLOR

      public static final int IMREAD_ANYCOLOR
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    • IMREAD_LOAD_GDAL

      public static final int IMREAD_LOAD_GDAL
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    • IMREAD_REDUCED_GRAYSCALE_2

      public static final int IMREAD_REDUCED_GRAYSCALE_2
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    • IMREAD_REDUCED_COLOR_2

      public static final int IMREAD_REDUCED_COLOR_2
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    • IMREAD_REDUCED_GRAYSCALE_4

      public static final int IMREAD_REDUCED_GRAYSCALE_4
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    • IMREAD_REDUCED_COLOR_4

      public static final int IMREAD_REDUCED_COLOR_4
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    • IMREAD_REDUCED_GRAYSCALE_8

      public static final int IMREAD_REDUCED_GRAYSCALE_8
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    • IMREAD_REDUCED_COLOR_8

      public static final int IMREAD_REDUCED_COLOR_8
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    • IMREAD_IGNORE_ORIENTATION

      public static final int IMREAD_IGNORE_ORIENTATION
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    • IMWRITE_EXR_COMPRESSION_NO

      public static final int IMWRITE_EXR_COMPRESSION_NO
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    • IMWRITE_EXR_COMPRESSION_RLE

      public static final int IMWRITE_EXR_COMPRESSION_RLE
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    • IMWRITE_EXR_COMPRESSION_ZIPS

      public static final int IMWRITE_EXR_COMPRESSION_ZIPS
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    • IMWRITE_EXR_COMPRESSION_ZIP

      public static final int IMWRITE_EXR_COMPRESSION_ZIP
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    • IMWRITE_EXR_COMPRESSION_PIZ

      public static final int IMWRITE_EXR_COMPRESSION_PIZ
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    • IMWRITE_EXR_COMPRESSION_PXR24

      public static final int IMWRITE_EXR_COMPRESSION_PXR24
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    • IMWRITE_EXR_COMPRESSION_B44

      public static final int IMWRITE_EXR_COMPRESSION_B44
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    • IMWRITE_EXR_COMPRESSION_B44A

      public static final int IMWRITE_EXR_COMPRESSION_B44A
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    • IMWRITE_EXR_COMPRESSION_DWAA

      public static final int IMWRITE_EXR_COMPRESSION_DWAA
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    • IMWRITE_EXR_COMPRESSION_DWAB

      public static final int IMWRITE_EXR_COMPRESSION_DWAB
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    • IMWRITE_EXR_TYPE_HALF

      public static final int IMWRITE_EXR_TYPE_HALF
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    • IMWRITE_EXR_TYPE_FLOAT

      public static final int IMWRITE_EXR_TYPE_FLOAT
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    • IMWRITE_JPEG_QUALITY

      public static final int IMWRITE_JPEG_QUALITY
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    • IMWRITE_JPEG_PROGRESSIVE

      public static final int IMWRITE_JPEG_PROGRESSIVE
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    • IMWRITE_JPEG_OPTIMIZE

      public static final int IMWRITE_JPEG_OPTIMIZE
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    • IMWRITE_JPEG_RST_INTERVAL

      public static final int IMWRITE_JPEG_RST_INTERVAL
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    • IMWRITE_JPEG_LUMA_QUALITY

      public static final int IMWRITE_JPEG_LUMA_QUALITY
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    • IMWRITE_JPEG_CHROMA_QUALITY

      public static final int IMWRITE_JPEG_CHROMA_QUALITY
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    • IMWRITE_JPEG_SAMPLING_FACTOR

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR
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    • IMWRITE_PNG_COMPRESSION

      public static final int IMWRITE_PNG_COMPRESSION
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    • IMWRITE_PNG_STRATEGY

      public static final int IMWRITE_PNG_STRATEGY
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    • IMWRITE_PNG_BILEVEL

      public static final int IMWRITE_PNG_BILEVEL
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    • IMWRITE_PXM_BINARY

      public static final int IMWRITE_PXM_BINARY
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    • IMWRITE_EXR_TYPE

      public static final int IMWRITE_EXR_TYPE
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    • IMWRITE_EXR_COMPRESSION

      public static final int IMWRITE_EXR_COMPRESSION
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    • IMWRITE_EXR_DWA_COMPRESSION_LEVEL

      public static final int IMWRITE_EXR_DWA_COMPRESSION_LEVEL
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    • IMWRITE_WEBP_QUALITY

      public static final int IMWRITE_WEBP_QUALITY
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    • IMWRITE_HDR_COMPRESSION

      public static final int IMWRITE_HDR_COMPRESSION
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    • IMWRITE_PAM_TUPLETYPE

      public static final int IMWRITE_PAM_TUPLETYPE
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    • IMWRITE_TIFF_RESUNIT

      public static final int IMWRITE_TIFF_RESUNIT
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    • IMWRITE_TIFF_XDPI

      public static final int IMWRITE_TIFF_XDPI
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    • IMWRITE_TIFF_YDPI

      public static final int IMWRITE_TIFF_YDPI
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    • IMWRITE_TIFF_COMPRESSION

      public static final int IMWRITE_TIFF_COMPRESSION
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    • IMWRITE_JPEG2000_COMPRESSION_X1000

      public static final int IMWRITE_JPEG2000_COMPRESSION_X1000
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    • IMWRITE_HDR_COMPRESSION_NONE

      public static final int IMWRITE_HDR_COMPRESSION_NONE
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    • IMWRITE_HDR_COMPRESSION_RLE

      public static final int IMWRITE_HDR_COMPRESSION_RLE
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    • IMWRITE_JPEG_SAMPLING_FACTOR_411

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR_411
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    • IMWRITE_JPEG_SAMPLING_FACTOR_420

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR_420
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    • IMWRITE_JPEG_SAMPLING_FACTOR_422

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR_422
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    • IMWRITE_JPEG_SAMPLING_FACTOR_440

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR_440
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    • IMWRITE_JPEG_SAMPLING_FACTOR_444

      public static final int IMWRITE_JPEG_SAMPLING_FACTOR_444
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    • IMWRITE_PAM_FORMAT_NULL

      public static final int IMWRITE_PAM_FORMAT_NULL
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    • IMWRITE_PAM_FORMAT_BLACKANDWHITE

      public static final int IMWRITE_PAM_FORMAT_BLACKANDWHITE
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    • IMWRITE_PAM_FORMAT_GRAYSCALE

      public static final int IMWRITE_PAM_FORMAT_GRAYSCALE
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    • IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA

      public static final int IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA
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    • IMWRITE_PAM_FORMAT_RGB

      public static final int IMWRITE_PAM_FORMAT_RGB
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    • IMWRITE_PAM_FORMAT_RGB_ALPHA

      public static final int IMWRITE_PAM_FORMAT_RGB_ALPHA
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    • IMWRITE_PNG_STRATEGY_DEFAULT

      public static final int IMWRITE_PNG_STRATEGY_DEFAULT
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    • IMWRITE_PNG_STRATEGY_FILTERED

      public static final int IMWRITE_PNG_STRATEGY_FILTERED
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    • IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY

      public static final int IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY
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    • IMWRITE_PNG_STRATEGY_RLE

      public static final int IMWRITE_PNG_STRATEGY_RLE
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    • IMWRITE_PNG_STRATEGY_FIXED

      public static final int IMWRITE_PNG_STRATEGY_FIXED
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  • Constructor Details

    • Imgcodecs

      public Imgcodecs()
  • Method Details

    • imread

      public static Mat imread(String filename, int flags)
      Loads an image from a file. imread The function imread loads an image from the specified file and returns it. If the image cannot be read (because of missing file, improper permissions, unsupported or invalid format), the function returns an empty matrix ( Mat::data==NULL ). Currently, the following file formats are supported:
      • Windows bitmaps - \*.bmp, \*.dib (always supported)
      • JPEG files - \*.jpeg, \*.jpg, \*.jpe (see the *Note* section)
      • JPEG 2000 files - \*.jp2 (see the *Note* section)
      • Portable Network Graphics - \*.png (see the *Note* section)
      • WebP - \*.webp (see the *Note* section)
      • Portable image format - \*.pbm, \*.pgm, \*.ppm \*.pxm, \*.pnm (always supported)
      • PFM files - \*.pfm (see the *Note* section)
      • Sun rasters - \*.sr, \*.ras (always supported)
      • TIFF files - \*.tiff, \*.tif (see the *Note* section)
      • OpenEXR Image files - \*.exr (see the *Note* section)
      • Radiance HDR - \*.hdr, \*.pic (always supported)
      • Raster and Vector geospatial data supported by GDAL (see the *Note* section)
      Note:
      • The function determines the type of an image by the content, not by the file extension.
      • In the case of color images, the decoded images will have the channels stored in B G R order.
      • When using IMREAD_GRAYSCALE, the codec's internal grayscale conversion will be used, if available. Results may differ to the output of cvtColor()
      • On Microsoft Windows\* OS and MacOSX\*, the codecs shipped with an OpenCV image (libjpeg, libpng, libtiff, and libjasper) are used by default. So, OpenCV can always read JPEGs, PNGs, and TIFFs. On MacOSX, there is also an option to use native MacOSX image readers. But beware that currently these native image loaders give images with different pixel values because of the color management embedded into MacOSX.
      • On Linux\*, BSD flavors and other Unix-like open-source operating systems, OpenCV looks for codecs supplied with an OS image. Install the relevant packages (do not forget the development files, for example, "libjpeg-dev", in Debian\* and Ubuntu\*) to get the codec support or turn on the OPENCV_BUILD_3RDPARTY_LIBS flag in CMake.
      • In the case you set *WITH_GDAL* flag to true in CMake and REF: IMREAD_LOAD_GDAL to load the image, then the [GDAL](http://www.gdal.org) driver will be used in order to decode the image, supporting the following formats: [Raster](http://www.gdal.org/formats_list.html), [Vector](http://www.gdal.org/ogr_formats.html).
      • If EXIF information is embedded in the image file, the EXIF orientation will be taken into account and thus the image will be rotated accordingly except if the flags REF: IMREAD_IGNORE_ORIENTATION or REF: IMREAD_UNCHANGED are passed.
      • Use the IMREAD_UNCHANGED flag to keep the floating point values from PFM image.
      • By default number of pixels must be less than 2^30. Limit can be set using system variable OPENCV_IO_MAX_IMAGE_PIXELS
      Parameters:
      filename - Name of file to be loaded.
      flags - Flag that can take values of cv::ImreadModes
      Returns:
      automatically generated
    • imread

      public static Mat imread(String filename)
      Loads an image from a file. imread The function imread loads an image from the specified file and returns it. If the image cannot be read (because of missing file, improper permissions, unsupported or invalid format), the function returns an empty matrix ( Mat::data==NULL ). Currently, the following file formats are supported:
      • Windows bitmaps - \*.bmp, \*.dib (always supported)
      • JPEG files - \*.jpeg, \*.jpg, \*.jpe (see the *Note* section)
      • JPEG 2000 files - \*.jp2 (see the *Note* section)
      • Portable Network Graphics - \*.png (see the *Note* section)
      • WebP - \*.webp (see the *Note* section)
      • Portable image format - \*.pbm, \*.pgm, \*.ppm \*.pxm, \*.pnm (always supported)
      • PFM files - \*.pfm (see the *Note* section)
      • Sun rasters - \*.sr, \*.ras (always supported)
      • TIFF files - \*.tiff, \*.tif (see the *Note* section)
      • OpenEXR Image files - \*.exr (see the *Note* section)
      • Radiance HDR - \*.hdr, \*.pic (always supported)
      • Raster and Vector geospatial data supported by GDAL (see the *Note* section)
      Note:
      • The function determines the type of an image by the content, not by the file extension.
      • In the case of color images, the decoded images will have the channels stored in B G R order.
      • When using IMREAD_GRAYSCALE, the codec's internal grayscale conversion will be used, if available. Results may differ to the output of cvtColor()
      • On Microsoft Windows\* OS and MacOSX\*, the codecs shipped with an OpenCV image (libjpeg, libpng, libtiff, and libjasper) are used by default. So, OpenCV can always read JPEGs, PNGs, and TIFFs. On MacOSX, there is also an option to use native MacOSX image readers. But beware that currently these native image loaders give images with different pixel values because of the color management embedded into MacOSX.
      • On Linux\*, BSD flavors and other Unix-like open-source operating systems, OpenCV looks for codecs supplied with an OS image. Install the relevant packages (do not forget the development files, for example, "libjpeg-dev", in Debian\* and Ubuntu\*) to get the codec support or turn on the OPENCV_BUILD_3RDPARTY_LIBS flag in CMake.
      • In the case you set *WITH_GDAL* flag to true in CMake and REF: IMREAD_LOAD_GDAL to load the image, then the [GDAL](http://www.gdal.org) driver will be used in order to decode the image, supporting the following formats: [Raster](http://www.gdal.org/formats_list.html), [Vector](http://www.gdal.org/ogr_formats.html).
      • If EXIF information is embedded in the image file, the EXIF orientation will be taken into account and thus the image will be rotated accordingly except if the flags REF: IMREAD_IGNORE_ORIENTATION or REF: IMREAD_UNCHANGED are passed.
      • Use the IMREAD_UNCHANGED flag to keep the floating point values from PFM image.
      • By default number of pixels must be less than 2^30. Limit can be set using system variable OPENCV_IO_MAX_IMAGE_PIXELS
      Parameters:
      filename - Name of file to be loaded.
      Returns:
      automatically generated
    • imreadmulti

      public static boolean imreadmulti(String filename, List<Mat> mats, int flags)
      Loads a multi-page image from a file. The function imreadmulti loads a multi-page image from the specified file into a vector of Mat objects.
      Parameters:
      filename - Name of file to be loaded.
      mats - A vector of Mat objects holding each page.
      flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR. SEE: cv::imread
      Returns:
      automatically generated
    • imreadmulti

      public static boolean imreadmulti(String filename, List<Mat> mats)
      Loads a multi-page image from a file. The function imreadmulti loads a multi-page image from the specified file into a vector of Mat objects.
      Parameters:
      filename - Name of file to be loaded.
      mats - A vector of Mat objects holding each page. SEE: cv::imread
      Returns:
      automatically generated
    • imreadmulti

      public static boolean imreadmulti(String filename, List<Mat> mats, int start, int count, int flags)
      Loads a of images of a multi-page image from a file. The function imreadmulti loads a specified range from a multi-page image from the specified file into a vector of Mat objects.
      Parameters:
      filename - Name of file to be loaded.
      mats - A vector of Mat objects holding each page.
      start - Start index of the image to load
      count - Count number of images to load
      flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR. SEE: cv::imread
      Returns:
      automatically generated
    • imreadmulti

      public static boolean imreadmulti(String filename, List<Mat> mats, int start, int count)
      Loads a of images of a multi-page image from a file. The function imreadmulti loads a specified range from a multi-page image from the specified file into a vector of Mat objects.
      Parameters:
      filename - Name of file to be loaded.
      mats - A vector of Mat objects holding each page.
      start - Start index of the image to load
      count - Count number of images to load SEE: cv::imread
      Returns:
      automatically generated
    • imcount

      public static long imcount(String filename, int flags)
      Returns the number of images inside the give file The function imcount will return the number of pages in a multi-page image, or 1 for single-page images
      Parameters:
      filename - Name of file to be loaded.
      flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR.
      Returns:
      automatically generated
    • imcount

      public static long imcount(String filename)
      Returns the number of images inside the give file The function imcount will return the number of pages in a multi-page image, or 1 for single-page images
      Parameters:
      filename - Name of file to be loaded.
      Returns:
      automatically generated
    • imwrite

      public static boolean imwrite(String filename, Mat img, MatOfInt params)
      Saves an image to a specified file. The function imwrite saves the image to the specified file. The image format is chosen based on the filename extension (see cv::imread for the list of extensions). In general, only 8-bit single-channel or 3-channel (with 'BGR' channel order) images can be saved using this function, with these exceptions:
      • 16-bit unsigned (CV_16U) images can be saved in the case of PNG, JPEG 2000, and TIFF formats
      • 32-bit float (CV_32F) images can be saved in PFM, TIFF, OpenEXR, and Radiance HDR formats; 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel)
      • PNG images with an alpha channel can be saved using this function. To do this, create 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).
      • Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below).
      If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way. If the format, depth or channel order is different, use Mat::convertTo and cv::cvtColor to convert it before saving. Or, use the universal FileStorage I/O functions to save the image to XML or YAML format. The sample below shows how to create a BGRA image, how to set custom compression parameters and save it to a PNG file. It also demonstrates how to save multiple images in a TIFF file: INCLUDE: snippets/imgcodecs_imwrite.cpp
      Parameters:
      filename - Name of the file.
      img - (Mat or vector of Mat) Image or Images to be saved.
      params - Format-specific parameters encoded as pairs (paramId_1, paramValue_1, paramId_2, paramValue_2, ... .) see cv::ImwriteFlags
      Returns:
      automatically generated
    • imwrite

      public static boolean imwrite(String filename, Mat img)
      Saves an image to a specified file. The function imwrite saves the image to the specified file. The image format is chosen based on the filename extension (see cv::imread for the list of extensions). In general, only 8-bit single-channel or 3-channel (with 'BGR' channel order) images can be saved using this function, with these exceptions:
      • 16-bit unsigned (CV_16U) images can be saved in the case of PNG, JPEG 2000, and TIFF formats
      • 32-bit float (CV_32F) images can be saved in PFM, TIFF, OpenEXR, and Radiance HDR formats; 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel)
      • PNG images with an alpha channel can be saved using this function. To do this, create 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).
      • Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below).
      If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way. If the format, depth or channel order is different, use Mat::convertTo and cv::cvtColor to convert it before saving. Or, use the universal FileStorage I/O functions to save the image to XML or YAML format. The sample below shows how to create a BGRA image, how to set custom compression parameters and save it to a PNG file. It also demonstrates how to save multiple images in a TIFF file: INCLUDE: snippets/imgcodecs_imwrite.cpp
      Parameters:
      filename - Name of the file.
      img - (Mat or vector of Mat) Image or Images to be saved.
      Returns:
      automatically generated
    • imwritemulti

      public static boolean imwritemulti(String filename, List<Mat> img, MatOfInt params)
    • imwritemulti

      public static boolean imwritemulti(String filename, List<Mat> img)
    • imdecode

      public static Mat imdecode(Mat buf, int flags)
      Reads an image from a buffer in memory. The function imdecode reads an image from the specified buffer in the memory. If the buffer is too short or contains invalid data, the function returns an empty matrix ( Mat::data==NULL ). See cv::imread for the list of supported formats and flags description. Note: In the case of color images, the decoded images will have the channels stored in B G R order.
      Parameters:
      buf - Input array or vector of bytes.
      flags - The same flags as in cv::imread, see cv::ImreadModes.
      Returns:
      automatically generated
    • imdecodemulti

      public static boolean imdecodemulti(Mat buf, int flags, List<Mat> mats)
      Reads a multi-page image from a buffer in memory. The function imdecodemulti reads a multi-page image from the specified buffer in the memory. If the buffer is too short or contains invalid data, the function returns false. See cv::imreadmulti for the list of supported formats and flags description. Note: In the case of color images, the decoded images will have the channels stored in B G R order.
      Parameters:
      buf - Input array or vector of bytes.
      flags - The same flags as in cv::imread, see cv::ImreadModes.
      mats - A vector of Mat objects holding each page, if more than one.
      Returns:
      automatically generated
    • imencode

      public static boolean imencode(String ext, Mat img, MatOfByte buf, MatOfInt params)
      Encodes an image into a memory buffer. The function imencode compresses the image and stores it in the memory buffer that is resized to fit the result. See cv::imwrite for the list of supported formats and flags description.
      Parameters:
      ext - File extension that defines the output format. Must include a leading period.
      img - Image to be written.
      buf - Output buffer resized to fit the compressed image.
      params - Format-specific parameters. See cv::imwrite and cv::ImwriteFlags.
      Returns:
      automatically generated
    • imencode

      public static boolean imencode(String ext, Mat img, MatOfByte buf)
      Encodes an image into a memory buffer. The function imencode compresses the image and stores it in the memory buffer that is resized to fit the result. See cv::imwrite for the list of supported formats and flags description.
      Parameters:
      ext - File extension that defines the output format. Must include a leading period.
      img - Image to be written.
      buf - Output buffer resized to fit the compressed image.
      Returns:
      automatically generated
    • haveImageReader

      public static boolean haveImageReader(String filename)
      Returns true if the specified image can be decoded by OpenCV
      Parameters:
      filename - File name of the image
      Returns:
      automatically generated
    • haveImageWriter

      public static boolean haveImageWriter(String filename)
      Returns true if an image with the specified filename can be encoded by OpenCV
      Parameters:
      filename - File name of the image
      Returns:
      automatically generated