lib/dnn/image.rb in ruby-dnn-1.2.0 vs lib/dnn/image.rb in ruby-dnn-1.2.1

@@ -112,9 +112,44 @@
         x = x.mean(axis: 2, keepdims: true).concatenate(img[true, true, 3..3], axis: 2)
       end
       Numo::UInt8.cast(x)
     end
 
+    # Image convert image channel to RGB.
+    # @param [Numo::UInt8] img Image to RGB.
+    def self.to_rgb(img)
+      img_check(img)
+      case img.shape[2]
+      when 1
+        return img.concatenate(img, axis: 2).concatenate(img, axis: 2)
+      when 2
+        img = img[true, true, 0...1]
+        return img.concatenate(img, axis: 2).concatenate(img, axis: 2)
+      when 4
+        return img[true, true, 0...3].clone
+      end
+      img
+    end
+
+    # Image convert image channel to RGBA.
+    # @param [Numo::UInt8] img Image to RGBA.
+    def self.to_rgba(img)
+      img_check(img)
+      case img.shape[2]
+      when 1
+        alpha = Numo::UInt8.new(*img.shape[0..1], 1).fill(255)
+        return img.concatenate(img, axis: 2).concatenate(img, axis: 2).concatenate(alpha, axis: 2)
+      when 2
+        alpha = img[true, true, 1...2]
+        img = img[true, true, 0...1]
+        return img.concatenate(img, axis: 2).concatenate(img, axis: 2).concatenate(alpha, axis: 2)
+      when 3
+        alpha = Numo::UInt8.new(*img.shape[0..1], 1).fill(255)
+        return img.concatenate(alpha, axis: 2)
+      end
+      img
+    end
+
     private_class_method def self.img_check(img)
       raise TypeError, "img: #{img.class} is not an instance of the Numo::UInt8 class." unless img.is_a?(Numo::UInt8)
       if img.shape.length != 3
         raise ImageShapeError, "img shape is #{img.shape}. But img shape must be 3 dimensional."
       elsif !img.shape[2].between?(1, 4)