Images as arrays

JuliaImages are two-dimensional arrays, and every pixel can be either scalar or a one-dimensional array:

• Grayscale images represent pixels as scalar values and they are called Gray
• RGB is a three-dimensional array which represents each point in three different colors, such as red, green, and blue
• PNG images with a transparent background are called RGBA

Accessing pixels

When you use a load command in Julia, it reads the image and encodes it in RGB. In the following example, we will see how Julia manages information for a single pixel:

using Images
img = load("sample-images/cats-3061372_640.jpg")
img[1:1, 1:1, :]

After Julia executes the preceding set of commands, you should expect to see the following output:

julia> img[1:1, 1:1, :]
1×1×1 Array{RGB4{N0f8},3}:
[:, :, 1] =
 RGB4{N0f8}(0.349,0.282,0.212)

Pay attention to the last line. Our pixel is composed of an RGB object with 0.349,0.282,0.212 being the values corresponding to the values for each of the three channels. 

You will...