Quantization

Quantizes the image into discrete intensities levels.

Usage

Arrays, Grayscale Images and RGB Images

For arrays, grayscale images (Array{<:Gray}) and RGB images (Array{<:RGB}) we provide the following method:

quantization(X, levels; minv=0, maxv=1)

We round the intensities of the array values to levels different value levels. minv and maxv indicate the minimum and maximum value of the discretization interval. For Normed datatypes like Normed{UInt8, 8} you can't choose values above 1 and below 0.

Examples

Images

Some examples with images.

using Noise, TestImages, Images
img_gray = testimage("fabio_gray_256")
img_color = testimage("fabio_color_256")

img_gray_noise = quantization(img_gray, 20)
img_gray_noise_heavy= quantization(img_gray, 5)
img_color_noise = quantization(img_color, 10)

The images are in the same order as the commands are. The left image has 20 different value levels. The middle image only 5. The right image has 20 different value levels for each color channel.

Gray image with 20 levels	Gray image with 5 levels	RGB image with 20 color levels each

1D Arrays

Some examples with 1D arrays.

using Noise, Plots

x = LinRange(0.0, 10.0, 300)
y = sin.(x)
y_noise = quantization(y, 20, minv=-1, maxv=1)
y_noise_2 = quantization(y, 5, minv=-1, maxv=1)

plot(x,y);
plot!(x, y_noise);
plot!(x, y_noise_2);

qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: linuxfb, minimal, offscreen, vnc, xcb.

Aborted (core dumped)
connect: Connection refused
GKS: can't connect to GKS socket application

GKS: Open failed in routine OPEN_WS
GKS: GKS not in proper state. GKS must be either in the state WSOP or WSAC in routine ACTIVATE_WS

The green curve consists of 5 different levels, the orange one of 20. As it can be seen, already 20 different value sample the original signal quite good.