Downsample an image by discarding every odd row.

Downsample an image by discarding every odd column.

Downsample an image by discarding every odd row and column.

Upsample an image by inserting a row of back pixels after each row of a source image.

Upsample an image by inserting a column of back pixels after each column of a source image.

Upsample an image by inserting a row and a column of back pixels after each row and a column of a source image.

Concatenate two images together into one. Both input images must have the same number of rows.

Concatenate two images together into one. Both input images must have the same number of columns.

Crop an image, i.e. retrieves a sub-image image with m rows and n columns. Make sure (m + i, n + j) is not greater than dimensions of a source image.

Flip an image vertically.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_flipV.jpg" $ flipV frog

Flip an image horizontally.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_flipH.jpg" $ flipH frog

Rotate an image clockwise by 90°.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_rotate90.jpg" $ rotate90 frog

Rotate an image by 180°.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_rotate180.jpg" $ rotate180 frog

Rotate an image clockwise by 270°.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_rotate270.jpg" $ rotate270 frog

Rotate an image clockwise by an angle Θ in radians.

>>> frog <- readImageRGBA "images/frog.jpg"
>>> writeImage "images/frog_rotate330.png" $ rotate (Bilinear (Fill 0)) (11*pi/6) frog

Resize an image using an interpolation method.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_resize.jpg" $ resize (Bilinear Edge) (100, 640) frog

Scale an image. Same as resize, except scaling factors are supplied instead of new dimensions.

 scale (Bilinear Edge) (0.5, 2) frog == resize (Bilinear Edge) (100, 640) frog

Implementation for an interpolation method.

Nearest Neighbor interpolation method.

Bilinear interpolation method.

Convolution of an image using a kernel. Border resolution technique is required.

Example using Sobel operator:

>>> frog <- readImageY "frog.jpg"
>>> let frogX = convolve Edge (fromLists [[-1, 0, 1], [-2, 0, 2], [-1, 0, 1]]) frog
>>> let frogY = convolve Edge (fromLists [[-1,-2,-1], [ 0, 0, 0], [ 1, 2, 1]]) frog
>>> displayImage $ normalize $ sqrt (frogX ^ 2 + frogY ^ 2)

Convolve image's rows with a vector kernel represented by a list of pixels.

Convolve image's columns with a vector kernel represented by a list of pixels.

Approach to be used near the borders during various transformations. Whenever a function needs information not only about a pixel of interest, but also about it's neighbours, it will go out of bounds around the image edges, hence is this set of approaches that can be used in such situtation.

This function magnifies an image by a positive factor and draws a grid around the original pixels. It is here simply as useful inspection tool.

>>> frog <- readImageRGB "images/frog.jpg"
>>> writeImage "images/frog_eye_grid.png" $ pixelGrid 10 $ crop (51, 112) (20, 20) frog