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cv - Compare images (:cv_compare_image)

Declaration​

shapes, visualized = img:cv_compare_image(other_img[, options])

Parameters​

  • other_img
    Image object. The image to compare with

  • options
    Table

    Option fields
    {
        should_visualize = false | true,  -- optional, whether to output visualization, default false
        approx_epsilon = integer_value,   -- optional, contour approximation percentage of perimeter, simplifies complex contours, default 2
    }

Returns​

  • shapes
    Table. The list of difference shapes between the two images

    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​

Compare two images to find differences and return vertex lists of difference regions
The two images must have the same size

Example​

local cv = require("image.cv")
local img1 = image.load_file(XXT_SCRIPTS_PATH..'/1.png')
local img2 = image.load_file(XXT_SCRIPTS_PATH..'/2.png')
-- returns a list of shapes; may contain multiple shapes
local shapes, visimg = img1:cv_compare_image(img2)
nLog(shapes) -- print shapes
dialog():add_image(visimg):show() -- visualize difference image