//ProjectGray returns a greyscale sinogram (or radon projection) of img // N(default: 360): number of image rotation on which a projection will be done // A naive simplistic approach // Sinograms looks like this : // θ1 θ2 θ3...θN // | | | | // | | | | func ProjectGray(src image.Image, N int) (*image.Gray, error) { if N == 0 { N = 360 } step := 180.0 / float64(N) size := src.Bounds().Size() overX := int(float64(size.X) * 1.1) overY := int(float64(size.Y) * 1.1) var img image.Image = image.NewGray(image.Rect(0, 0, size.X+overX, size.Y+overY)) img = imaging.Overlay(img, src, image.Pt(overX/2, overY/2), 1) size = img.Bounds().Size() D := max(size.X, size.Y) out := image.NewGray(image.Rect(0, 0, N, D)) // for each given angle θ for n := 0; n < N; n++ { θ := float64(n) * step draw := image.NewRGBA(image.Rect(0, 0, img.Bounds().Dy(), img.Bounds().Dx())) //have a duplicate img rotated by θ err := graphics.Rotate(draw, img, &graphics.RotateOptions{Angle: manipulator.Rad(θ)}) if err != nil { return out, err } sinogram := make([]float64, size.X) // get column average profile for y := 0; y < size.Y; y++ { for x := 0; x < size.X; x++ { greyColor, _ := color.GrayModel.Convert(draw.At(x, y)).(color.Gray) sinogram[x] = sinogram[x] + float64(greyColor.Y) } } //Set out line with sinogram for d := 0; d < D; d++ { out.Set(n, d, color.Gray{uint8(sinogram[d] / float64(size.Y))}) } } return out, nil }
func Overlay(images []*ingest.Image) (*ingest.Image, error) { if len(images) == 0 { return nil, fmt.Errorf("empty slice was passed in") } else if len(images) == 1 { return images[0], nil } meta := CommonMeta(images) path := OverlayName(images) fi, err := os.Stat(path) if err != nil && os.IsNotExist(err) { // ok we will make it below } else if err != nil { return nil, err } else if fi.Size() > 0 { return &ingest.Image{path, meta}, nil } imgs := make([]image.Image, 0, len(images)) for _, i := range images { img, err := ingest.LoadImage(i.Path) if err != nil { return nil, err } imgs = append(imgs, img) } overlay := imgs[0] for i := 1; i < len(imgs); i++ { overlay = imaging.Overlay(overlay, imgs[i], image.Pt(0, 0), .50) } err = ingest.WriteJpeg(path, overlay) if err != nil { return nil, err } return &ingest.Image{path, meta}, nil }