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cv - Convert image to contour shapes (:cv_to_shapes)

Declaration​

shapes, visualized = img:cv_to_shapes([ options ])

Parameters​

  • options
    Optional, table

    Option fields
    {
        should_visualize = false | true,  -- optional, whether to output visualization, default false
        closed = false | true,            -- optional, whether shapes are closed, default false
        blur_size = integer_value,        -- optional, blur kernel size, positive odd number only, default 3
        canny_threshold1 = 100,           -- optional, Canny lower threshold, default 100
        canny_threshold2 = 200,           -- optional, Canny upper threshold, default 200
        approx_epsilon = integer_value,   -- optional, contour approximation percentage of perimeter, default 2
    }

Returns​

  • shapes
    Table. List of shapes on the image

    Shapes structure
    {
        { -- shape 1
            { -- vertex 1
                ["y"] = number_value,
                ["x"] = number_value,
            },
            { -- vertex 2
                ["y"] = number_value,
                ["x"] = number_value,
            },
            ...
        },
        { -- shape 2
            { -- vertex 1
                ["y"] = number_value,
                ["x"] = number_value,
            },
            { -- vertex 2
                ["y"] = number_value,
                ["x"] = number_value,
            },
            ...
        },
        ...
    }

  • visualized
    Image object. When options.should_visualize is true, this is the visualization image

Description​

Convert contours on the image into shapes (vertex lists)
Prefer simple, clear, closed shapes for better results

Example​

local cv = require("image.cv")
local img = image.load_file(XXT_SCRIPTS_PATH..'/1.png')
local shapes, visimg = img:cv_to_shapes({
    blur_size = 3,
    approx_epsilon = 2,
    closed = true,
    should_visualize = true,
})
nLog(shapes)
dialog():add_image(visimg):show()