adaptiveThreshold | R Documentation |
adaptiveThreshold
transforms a grayscale image to a
binary image using an adaptive threshold.
adaptiveThreshold(
image,
max_value = 255,
method = "mean",
threshold_type = "inverse",
block_size = 31,
C = 25,
target = "new",
in_place = NULL
)
image |
An an 8-bit (8U) single-channel |
max_value |
Non-zero value assigned to the pixels for which the condition determined by 'threshold_type' is satisfied (default: 255). |
method |
The name of the adaptive thresholding algorithm to use. It can be either 'mean' - mean of the block_size * block_size neighborhood - or 'gaussian' - Gaussian weighted sum of the block_size * block_size neighborhood (default: 'mean'). |
threshold_type |
The name of the threshold type to use. It can be either 'binary' or 'inverse' (default: 'inverse'). If 'binary', each pixel is replaced by 'max_value' if its value is above the adaptive threshold, and by zero otherwise. If 'inverse' each pixel is replaced by zero if its value is above the adaptive threshold, and by 'max_value' otherwise. |
block_size |
Size of a pixel neighborhood that is used to calculate a threshold value for the pixel (default: 31). It must be an odd number greater than 1. |
C |
Constant subtracted from the mean or weighted mean. Normally, it is positive but may be zero or negative as well (default: 25). |
target |
The location where the results should be stored. It can take 3 values:
|
in_place |
Deprecated. Use |
If target="new"
, the function returns an Image
object. If target="self"
, the function returns nothing and modifies
image
in place. If target
is an Image
object,
the function returns nothing and modifies that Image
object in
place.
Simon Garnier, garnier@njit.edu
Image
balloon <- image(system.file("sample_img/balloon1.png", package = "Rvision"))
balloon_gray <- changeColorSpace(balloon, "GRAY")
balloon_th <- adaptiveThreshold(balloon_gray)
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