Package deepnetts.util

Class ImageUtils

java.lang.Object

deepnetts.util.ImageUtils

public final class ImageUtils
extends Object

Utility methods to work with images. https://machinelearningmastery.com/best-practices-for-preparing-and-augmenting-image-data-for-convolutional-neural-networks/ random rescaling, horizontal flips, perturbations to brightness, contrast, and color, as well as random cropping. https://mxnet.apache.org/versions/1.5.0/tutorials/python/types_of_data_augmentation.html

Method Summary

Modifier and Type	Method	Description
static void	createIndexFile(HashMap<File,BufferedImage> imageMap, String imageFile, boolean useAbsPath)
static List<BufferedImage>	cropAtCornersAndCenter(BufferedImage img, int cropWidth, int cropHeight)	Returns five crops of a given image: four from each corner and one at center
static BufferedImage	flipHorizontal(BufferedImage img)
static BufferedImage	flipVertical(BufferedImage img)
static void	generateNoisyImage(int width, int height, int numberOfImages, String destPath)
static void	generateRandomColoredImages(int width, int height, int numberOfImages, String destPath)	Generates a specified number of randomly full colored images of a specified size.
static void	generateRandomFilledRectImages(int width, int height, int numberOfImages, String destPath)
static String	getImageType(File file)	Returns the extension of the given image file.
static BufferedImage	grayscale(BufferedImage img)	Returns grayscale version of the given image.
static HashMap<File,BufferedImage>	loadFileImageMapFromDirectory(File dir)	Loads JPG, JPEG or PNG images from specified directory and returns them as a map with File object as a key and BufferedImage object as a value.
static List<BufferedImage>	loadImagesFromDirectory(File dir)	Loads all images from the specified directory, and returns them as a list.
static BufferedImage	randomCrop(BufferedImage img, int cropWidth, int cropHeight)	Randomly crop image with specified width and height.
static List<BufferedImage>	randomCrop(BufferedImage img, int cropWidth, int cropHeight, int cropNum, Random random)	Crops specified number of random sub-images with specified dimensions.
static BufferedImage	randomTintAndBrightness(BufferedImage img)
static List<BufferedImage>	randomTintAndBrightness(BufferedImage img, float maxTint, int maxBrightness, int num, Random random)	Still not working as it should
static BufferedImage[]	randomTranslateImage(BufferedImage img, int stepCount, int stepSize)	Returns an array of images created by translating specified input image by specified number of count with specified step size.
static BufferedImage	scaleAndCenter(BufferedImage img, int targetWidth, int targetHeight, int padding, Color bgColor)	Scales input image to specified target width or height, centers and returns resulting image.
static BufferedImage	scaleBySmallerAndCrop(BufferedImage img, int targetWidth, int targetHeight)	Scales input image to specified target width or height, crops and returns resulting image.
static BufferedImage	scaleBySmallerTarget(BufferedImage img, int targetWidth, int targetHeight)
static BufferedImage	scaleImage(BufferedImage img, int newWidth, int newHeight)	Scales specified image to given size and returns new image with specified width and height.
static List<BufferedImage>	translateImage(BufferedImage img)	Generates 4 translated variations of the given image: translates it for one third of an image width and height in each direction.
static void	writeImages(List<BufferedImage> images, String targetPath, String fileNamePrefix, String fileType)	Writes list of images to specified file path.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

translateImage

public static List<BufferedImage> translateImage(BufferedImage img)

Generates 4 translated variations of the given image: translates it for one third of an image width and height in each direction. Uses black color to fill background extra space. TODO: add param for background color or pattern to use to fill the empty space.

Parameters:

img - image to translate

Returns:

scaleImage

public static BufferedImage scaleImage(BufferedImage img,
 int newWidth,
 int newHeight)

Scales specified image to given size and returns new image with specified width and height. Original image is not changed..

Parameters:

img - image to sclae

newWidth - width of scaled image

newHeight - height of scaled image

Returns:

scaleAndCenter

public static BufferedImage scaleAndCenter(BufferedImage img,
 int targetWidth,
 int targetHeight,
 int padding,
 Color bgColor)

Scales input image to specified target width or height, centers and returns resulting image. Scaling factor is calculated using larger dimension (width or height). Keeps aspect ratio and image type, and bgColor parameter to fill background.

Parameters:

img - image to scale

targetWidth - witdth to scale to

targetHeight - height to scale to

padding - minimalno rastojanje od ivica slike koja se smanjuje i centrira

bgColor - , umesto bgColor bolje da bude neki pattern koji popinjava tipa random pixels

Returns:

scaled and centered image

scaleBySmallerAndCrop

public static BufferedImage scaleBySmallerAndCrop(BufferedImage img,
 int targetWidth,
 int targetHeight)

Scales input image to specified target width or height, crops and returns resulting image. Scaling factor is calculated using smaller dimension (width or height). Keeps aspect ratio and image type, and bgColor parameter to fill background.

Parameters:

img - image to scale

targetWidth - target image width

targetHeight - target image height

Returns:

scaled and cropped image

scaleBySmallerTarget

public static BufferedImage scaleBySmallerTarget(BufferedImage img,
 int targetWidth,
 int targetHeight)

flipHorizontal

public static BufferedImage flipHorizontal(BufferedImage img)

flipVertical

public static BufferedImage flipVertical(BufferedImage img)

loadImagesFromDirectory

public static List<BufferedImage> loadImagesFromDirectory(File dir)
                                                   throws IOException

Loads all images from the specified directory, and returns them as a list.

Parameters:

dir -

Returns:

list of images as BufferedImage instances

Throws:

IOException

loadFileImageMapFromDirectory

public static HashMap<File,BufferedImage> loadFileImageMapFromDirectory(File dir)
                                                                 throws IOException

Loads JPG, JPEG or PNG images from specified directory and returns them as a map with File object as a key and BufferedImage object as a value. Skips all subdirectories.

Parameters:

dir - directory to load

Returns:

map of files and images.

Throws:

IOException

getImageType

public static String getImageType(File file)

Returns the extension of the given image file.

Parameters:

file -

Returns:

grayscale

public static BufferedImage grayscale(BufferedImage img)

Returns grayscale version of the given image. Original image is not changed.

Parameters:

img -

Returns:

createIndexFile

public static void createIndexFile(HashMap<File,BufferedImage> imageMap,
 String imageFile,
 boolean useAbsPath)
                            throws IOException

Parameters:

imageMap -

imageFile -

useAbsPath -

Throws:

IOException

randomTranslateImage

public static BufferedImage[] randomTranslateImage(BufferedImage img,
 int stepCount,
 int stepSize)

Returns an array of images created by translating specified input image by specified number of count with specified step size.

Parameters:

img - image to translate

stepCount - number of

stepSize -

Returns:

randomCrop

public static List<BufferedImage> randomCrop(BufferedImage img,
 int cropWidth,
 int cropHeight,
 int cropNum,
 Random random)

Crops specified number of random sub-images with specified dimensions.

Parameters:

img - image to crop

cropWidth - width of the cropped image

cropHeight - height of the cropped image

cropNum - number of images to crop

random - random number generator used to generate random positions

Returns:

list of randomly cropped images

cropAtCornersAndCenter

public static List<BufferedImage> cropAtCornersAndCenter(BufferedImage img,
 int cropWidth,
 int cropHeight)

Returns five crops of a given image: four from each corner and one at center

Parameters:

img - image to crop

cropWidth - width of the cropped area

cropHeight - height of the cropped area

Returns:

five crops from the corners and center of the image

randomCrop

public static BufferedImage randomCrop(BufferedImage img,
 int cropWidth,
 int cropHeight)

Randomly crop image with specified width and height. Returns cropped image, while original image is unchanged.

Parameters:

img -

cropWidth -

cropHeight -

Returns:

cropped image

randomTintAndBrightness

public static List<BufferedImage> randomTintAndBrightness(BufferedImage img,
 float maxTint,
 int maxBrightness,
 int num,
 Random random)

Still not working as it should

Parameters:

img -

tint -

brightness -

Returns:

https://en.wikipedia.org/wiki/Normalization_(image_processing)

randomTintAndBrightness

public static BufferedImage randomTintAndBrightness(BufferedImage img)

writeImages

public static void writeImages(List<BufferedImage> images,
 String targetPath,
 String fileNamePrefix,
 String fileType)
                        throws IOException

Writes list of images to specified file path.

Parameters:

images - images to write

targetPath - path to write to

fileNamePrefix - prefix of image file name to use (eg. for prefix pattern "someImage" it will create file someImage_1.jpg )

fileType - type of file/images to write

Throws:

IOException

generateRandomColoredImages

public static void generateRandomColoredImages(int width,
 int height,
 int numberOfImages,
 String destPath)
                                        throws IOException

Generates a specified number of randomly full colored images of a specified size. Images are saved at specified destination path named using negative_x.jpg name pattern

Parameters:

width - image width

height - image height

numberOfImages - number of images to generate

destPath - destination path to save images

Throws:

IOException

generateRandomFilledRectImages

public static void generateRandomFilledRectImages(int width,
 int height,
 int numberOfImages,
 String destPath)
                                           throws IOException

Throws:

IOException

generateNoisyImage

public static void generateNoisyImage(int width,
 int height,
 int numberOfImages,
 String destPath)
                               throws IOException

Throws:

IOException