imaging/convolution_test.go

package imaging

import (
	"image"
	"testing"
)

func TestConvolve3x3(t *testing.T) {
	testCases := []struct {
		name    string
		src     image.Image
		kernel  [9]float64
		options *ConvolveOptions
		want    *image.NRGBA
	}{
		{
			"Convolve3x3 0x0",
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 0, 0),
				Stride: 0,
				Pix:    []uint8{},
			},
			[9]float64{
				0, 0, 0,
				0, 1, 0,
				0, 0, 0,
			},
			nil,
			&image.NRGBA{Rect: image.Rect(0, 0, 0, 0)},
		},
		{
			"Convolve3x3 4x4 identity",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 3, 3),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
			[9]float64{
				0, 0, 0,
				0, 1, 0,
				0, 0, 0,
			},
			nil,
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 4, 4),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
		},
		{
			"Convolve3x3 4x4 abs",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 3, 3),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
			[9]float64{
				0, 0, 0,
				0, -1, 0,
				0, 0, 0,
			},
			&ConvolveOptions{Abs: true},
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 4, 4),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
		},
		{
			"Convolve3x3 4x4 bias",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 3, 3),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
			[9]float64{
				0, 0, 0,
				0, 1, 0,
				0, 0, 0,
			},
			&ConvolveOptions{Bias: 0x10},
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 4, 4),
				Stride: 4 * 4,
				Pix: []uint8{
					0x10, 0x11, 0x12, 0x03, 0x14, 0x15, 0x16, 0x07, 0x18, 0x19, 0x1a, 0x0b, 0x1c, 0x1d, 0x1e, 0x0f,
					0x20, 0x21, 0x22, 0x13, 0x24, 0x25, 0x26, 0x17, 0x28, 0x29, 0x2a, 0x1b, 0x2c, 0x2d, 0x2e, 0x1f,
					0x30, 0x31, 0x32, 0x23, 0x34, 0x35, 0x36, 0x27, 0x38, 0x39, 0x3a, 0x2b, 0x3c, 0x3d, 0x3e, 0x2f,
					0x40, 0x41, 0x42, 0x33, 0x44, 0x45, 0x46, 0x37, 0x48, 0x49, 0x4a, 0x3b, 0x4c, 0x4d, 0x4e, 0x3f,
				},
			},
		},
		{
			"Convolve3x3 4x4 norm",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 3, 3),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
			[9]float64{
				1, 1, 1,
				1, 1, 1,
				1, 1, 1,
			},
			&ConvolveOptions{Normalize: true},
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 4, 4),
				Stride: 4 * 4,
				Pix: []uint8{
					0x07, 0x08, 0x09, 0x03, 0x09, 0x0a, 0x0b, 0x07, 0x0d, 0x0e, 0x0f, 0x0b, 0x10, 0x11, 0x12, 0x0f,
					0x11, 0x12, 0x13, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1b, 0x1c, 0x1d, 0x1f,
					0x21, 0x22, 0x23, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2b, 0x2c, 0x2d, 0x2f,
					0x2c, 0x2d, 0x2e, 0x33, 0x2f, 0x30, 0x31, 0x37, 0x33, 0x34, 0x35, 0x3b, 0x35, 0x36, 0x37, 0x3f,
				},
			},
		},
		{
			"Convolve3x3 3x3 laplacian",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 2, 2),
				Stride: 3 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x01, 0xff, 0x00, 0x01, 0x02, 0xff, 0x00, 0x01, 0x03, 0xff,
					0x00, 0x01, 0x04, 0xff, 0x10, 0x10, 0x10, 0xff, 0x00, 0x01, 0x05, 0xff,
					0x00, 0x01, 0x06, 0xff, 0x00, 0x01, 0x07, 0xff, 0x00, 0x01, 0x08, 0xff,
				},
			},
			[9]float64{
				-1, -1, -1,
				-1, 8, -1,
				-1, -1, -1,
			},
			nil,
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 3, 3),
				Stride: 3 * 4,
				Pix: []uint8{
					0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff,
					0x00, 0x00, 0x00, 0xff, 0x80, 0x78, 0x5c, 0xff, 0x00, 0x00, 0x00, 0xff,
					0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0x00, 0x00, 0xff,
				},
			},
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			got := Convolve3x3(tc.src, tc.kernel, tc.options)
			if !compareNRGBA(got, tc.want, 0) {
				t.Fatalf("got result %#v want %#v", got, tc.want)
			}
		})
	}
}

func TestConvolve5x5(t *testing.T) {
	testCases := []struct {
		name    string
		src     image.Image
		kernel  [25]float64
		options *ConvolveOptions
		want    *image.NRGBA
	}{
		{
			"Convolve5x5 4x4 translate",
			&image.NRGBA{
				Rect:   image.Rect(-1, -1, 3, 3),
				Stride: 4 * 4,
				Pix: []uint8{
					0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
					0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
					0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
					0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
			[25]float64{
				0, 0, 0, 0, 0,
				0, 0, 0, 0, 0,
				0, 0, 0, 0, 0,
				0, 0, 0, 0, 0,
				0, 0, 0, 0, 1,
			},
			nil,
			&image.NRGBA{
				Rect:   image.Rect(0, 0, 4, 4),
				Stride: 4 * 4,
				Pix: []uint8{
					0x28, 0x29, 0x2a, 0x03, 0x2c, 0x2d, 0x2e, 0x07, 0x2c, 0x2d, 0x2e, 0x0b, 0x2c, 0x2d, 0x2e, 0x0f,
					0x38, 0x39, 0x3a, 0x13, 0x3c, 0x3d, 0x3e, 0x17, 0x3c, 0x3d, 0x3e, 0x1b, 0x3c, 0x3d, 0x3e, 0x1f,
					0x38, 0x39, 0x3a, 0x23, 0x3c, 0x3d, 0x3e, 0x27, 0x3c, 0x3d, 0x3e, 0x2b, 0x3c, 0x3d, 0x3e, 0x2f,
					0x38, 0x39, 0x3a, 0x33, 0x3c, 0x3d, 0x3e, 0x37, 0x3c, 0x3d, 0x3e, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
				},
			},
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			got := Convolve5x5(tc.src, tc.kernel, tc.options)
			if !compareNRGBA(got, tc.want, 0) {
				t.Fatalf("got result %#v want %#v", got, tc.want)
			}
		})
	}
}

func TestNormalizeKernel(t *testing.T) {
	testCases := []struct {
		name   string
		kernel []float64
		want   []float64
	}{
		{
			name: "positive sum",
			kernel: []float64{
				2, 0, 2,
				0, 2, 0,
				2, 0, 2,
			},
			want: []float64{
				0.2, 0, 0.2,
				0, 0.2, 0,
				0.2, 0, 0.2,
			},
		},
		{
			name: "negative sum",
			kernel: []float64{
				-2, 0, -2,
				2, 2, 2,
				-2, 0, -2,
			},
			want: []float64{
				1, 0, 1,
				-1, -1, -1,
				1, 0, 1,
			},
		},
		{
			name: "zero sum",
			kernel: []float64{
				0, 2, 0,
				2, 0, -2,
				0, -2, 0,
			},
			want: []float64{
				0, 0.5, 0,
				0.5, 0, -0.5,
				0, -0.5, 0,
			},
		},
		{
			name: "all zero",
			kernel: []float64{
				0, 0, 0,
				0, 0, 0,
				0, 0, 0,
			},
			want: []float64{
				0, 0, 0,
				0, 0, 0,
				0, 0, 0,
			},
		},
	}
	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			normalizeKernel(tc.kernel)
			for i := range tc.kernel {
				if tc.kernel[i] != tc.want[i] {
					t.Fatalf("got kernel %v want %v", tc.kernel, tc.want)
				}
			}
		})
	}
}

func BenchmarkConvolve3x3(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		Convolve3x3(
			testdataBranchesJPG,
			[9]float64{
				-1, -1, 0,
				-1, 0, 1,
				0, 1, 1,
			},
			nil,
		)
	}
}

func BenchmarkConvolve5x5(b *testing.B) {
	b.ReportAllocs()
	for i := 0; i < b.N; i++ {
		Convolve5x5(
			testdataBranchesJPG,
			[25]float64{
				-1, -1, -1, -1, 0,
				-1, -1, -1, 0, 1,
				-1, -1, 0, 1, 1,
				-1, 0, 1, 1, 1,
				0, 1, 1, 1, 1,
			},
			nil,
		)
	}
}