Black and white

Binarizes an image according to the given threshold.

The pixels darker than the threshold become black and the pixels brighter than the threshold become white. If the threshold is negative, the image is binarized automatically with a threshold which best separates dark and bright pixels.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• threshold

  – Threshold which separates dark and bright pixels. A negative value means automatic thresholding.

Outputs

• image – Binarized black and white 8-bit gray-level image in gray8 format. The size of the output image is the same as the size of the input image. The intensity of black is zero and the intensity of white is 255.

Blur

Blurs the image using a Gaussian filter.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• filterSize

  – Size of the Gaussian filter. The bigger the size, the more the image is blurred. For instance, 5 gives light blurring and 99 (which is the maximum value) gives heavy blurring.

Outputs

• image – Blurred image. The size and format of the output image are the same as those of the input image.

Color distance

Returns a grayscale image which is constructed by measuring the difference between the color of each pixel and the reference color.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• referenceColor

  – The color to measure distance from. The better a pixel in the input image matches with the reference color, the brighter the corresponding pixel in the output image will be. The color is given in "#rrggbb" hexadecimal format. For example, "#ff0000" means red, "#00ff00" means green and "#0000ff" means blue.

Outputs

• image – A grayscale image in gray8 format. The image represents color distance map to the specified reference color.

Crop

Crops an area from the input image.

The area is defined by the pixel coordinates of the top-left corner and width and height of the cropped image.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• x

  – X-coordinate of the top-left corner of the sub-image.

• y

  – Y-coordinate of the top-left corner of the sub-image.

• width

  – Width of the sub-image in pixels.

• height

  – Height of the sub-image in pixels.

Outputs

• image – Output image. The format of the output image is the same as that of the input image. If a part (or even all) of the sub-image does not overlap with the input image, the non-overlapping area will be black. If width or height is negative, the output image will be empty. Negative x and y values are allowed.

Crop center

Crops an area from the center of the input image.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• width

  – Width of the crop area in pixels.

• height

  – Height of the crop area in pixels.

Outputs

• image – Output image. The format of the output image is the same as that of the input image. If width or height are larger than the size of the input image, the area outside the input image will be black. If width or height is negative, the output image will be empty.

Edges

Produces a black-and-white (binary) image where the edges of the objects in the input image are shown.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• smoothness

  – Determines how much blurring is applied to the input image prior to finding the edges. If smoothness = 0, there is no smoothing and plenty of edges will be drawn. If smoothness = 10 (which is the maximum value), there will be few edges and the edges will appear to be rounded.

Outputs

• image – Binary image in gray8 format. The edges are drawn with white color (255) on black background (0). The size of the output image is the same as the size of the input image.

Gray

Converts the input image to grayscale.

Inputs

• image – Input image in rgb, rgba or gray8 format.

Outputs

• image – Grayscale image in gray8 format. The size of the output image is the same as the size of the input image.

Huemap

Sets the chromaticity of a pixel in the output image according to the brightness of the corresponding pixel in the input image.

The smallest possible intensity is mapped to lowIntensityHue and the largest possible intensity to highIntensityHue. Chromacity values for other intensities are determined with linear interpolation. The chromacity values are given in degrees which describe rotation on circular color plane. For full color circle, set highIntensityHue = 0 and lowIntensityHue = 360.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• lowIntensityHue

  – Chromaticity value to which darkest pixels are mapped. Some examples of the mapping between degrees of rotation and colors are:

  Rotation	Color
  0 deg	Red
  60 deg	Yellow
  120 deg	Green
  180 deg	Cyan
  240 deg	Blue
  300 deg	Magenta
  360 deg	Red

• highIntensityHue – - Chromaticity value to which highest intensity pixels are mapped.

Outputs

• image – Output image in rgba (if input has alpha channel) or rgb (otherwise) format. The size of the output image is the same as the size of the input image.

Invert

Inverts the colors of the input image.

Inputs

• image – Input image in rgb, rgba or gray8 format.

Outputs

• image – Inverted image. If the input is a color image, each color channel will be inverted individually. The size and format of the output image are the same as those of the input image.

Mirror

Mirrors an input image about its vertical axis.

Inputs

• image – Input image in rgb, rgba or gray8 format.

Outputs

• image – Mirrored image. The format and size of the output image are the same as those of the input image.

Rotate

Rotates an input image about its center.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• angle

  – Rotation angle in degrees. Positive angle means clockwise rotation. Negative angle means counter-clockwise rotation.

Outputs

• image – Rotated image The format of the output image is the same as that of the input image. The size is large enough to contain the rotated image without clipping.

Sharpen

Sharpens the edges of the objects in the input image.

For instance, sharpening can make slightly blurred text easier to read.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• weight

  – Weight of the sharpening mask. The bigger the weight, the more sharpening is applied. Zero means no sharpening. Typically values between 1 and 10 give the best results.

Outputs

• image – Sharpened image. The size and format of the output image are the same as those of the input image.

Single color

Produces a single-color image where each pixel has the same hue but different intensity, like in a grayscale image.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• hue

  – Chromaticity value in hue degrees. Some examples of the mapping between degrees of rotation and colors are:

  Rotation	Color
  0 deg	Red
  60 deg	Yellow
  120 deg	Green
  180 deg	Cyan
  240 deg	Blue
  300 deg	Magenta
  360 deg	Red

• saturation – - The target saturation of the result color. The value range is 0-1. 0.0 means grayscale, 1.0 means fully saturated.

Outputs

• image – Output image in rgba (if input has alpha channel) or rgb (otherwise) format. The size of the output image is the same as the size of the input image.

Stretch

Stretch (or shrink) the input image into the given size.

Inputs

• image

  – Input image in rgb, rgba or gray8 format.

• width

  – Width of the output image in pixels.

• height

  – Height of the output image in pixels.

Outputs

• image – Output image. The format of the output image is the same as that of the input image. The size is determined by width and height.