diff --git a/src/TensorFlowNET.Core/APIs/tf.array.cs b/src/TensorFlowNET.Core/APIs/tf.array.cs
index f2402a6f..df8e69c3 100644
--- a/src/TensorFlowNET.Core/APIs/tf.array.cs
+++ b/src/TensorFlowNET.Core/APIs/tf.array.cs
@@ -139,5 +139,16 @@ namespace Tensorflow
         /// <returns></returns>
         public Tensor shape(Tensor input, string name = null, TF_DataType out_type = TF_DataType.TF_INT32)
             => array_ops.shape_internal(input, name, optimize: true, out_type: out_type);
+
+        /// <summary>
+        /// Unpacks the given dimension of a rank-`R` tensor into rank-`(R-1)` tensors.
+        /// </summary>
+        /// <param name="value"></param>
+        /// <param name="num"></param>
+        /// <param name="axis"></param>
+        /// <param name="name"></param>
+        /// <returns></returns>
+        public Tensor[] unstack(Tensor value, int? num = null, int axis = 0, string name = "unstack")
+            => array_ops.unstack(value, num: num, axis: axis, name: name);
     }
 }
diff --git a/src/TensorFlowNET.Core/APIs/tf.image.cs b/src/TensorFlowNET.Core/APIs/tf.image.cs
index 832010e5..57b8b093 100644
--- a/src/TensorFlowNET.Core/APIs/tf.image.cs
+++ b/src/TensorFlowNET.Core/APIs/tf.image.cs
@@ -40,6 +40,11 @@ namespace Tensorflow
             public Tensor resize_bilinear(Tensor images, Tensor size, bool align_corners = false, string name = null)
                 => gen_image_ops.resize_bilinear(images, size, align_corners: align_corners, name: name);
 
+            public Tensor resize_images(Tensor images, Tensor size, ResizeMethod method = ResizeMethod.BILINEAR,
+                    bool align_corners = false, bool preserve_aspect_ratio = false, string name = null)
+                => image_ops_impl.resize_images(images, size, method: method,
+                    align_corners: align_corners, preserve_aspect_ratio: preserve_aspect_ratio, name: name);
+
             public Tensor convert_image_dtype(Tensor image, TF_DataType dtype, bool saturate = false, string name = null)
                 => gen_image_ops.convert_image_dtype(image, dtype, saturate: saturate, name: name);
 
diff --git a/src/TensorFlowNET.Core/Operations/array_ops.py.cs b/src/TensorFlowNET.Core/Operations/array_ops.py.cs
index 83a469dc..c52e2821 100644
--- a/src/TensorFlowNET.Core/Operations/array_ops.py.cs
+++ b/src/TensorFlowNET.Core/Operations/array_ops.py.cs
@@ -308,6 +308,18 @@ namespace Tensorflow
         public static (Tensor, Tensor) unique(Tensor x, TF_DataType out_idx = TF_DataType.TF_INT32, string name = null)
             => gen_array_ops.unique(x, out_idx: out_idx, name: name);
 
+        public static Tensor[] unstack(Tensor value, int? num = null, int axis = 0, string name = "unstack")
+        {
+            if(num == null)
+            {
+                value = ops.convert_to_tensor(value);
+                var value_shape = value.TensorShape;
+                num = value_shape.dims[axis];
+            }
+
+            return gen_array_ops.unpack(value, num: num.Value, axis: axis, name: name);
+        }
+
         public static Tensor where(Tensor condition, object x = null, object y = null, string name = null)
         {
             if( x == null && y == null)
diff --git a/src/TensorFlowNET.Core/Operations/gen_array_ops.cs b/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
index ea020599..3e9ce699 100644
--- a/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
+++ b/src/TensorFlowNET.Core/Operations/gen_array_ops.cs
@@ -248,6 +248,12 @@ namespace Tensorflow
             return (_op.outputs[0], _op.outputs[1]);
         }
 
+        public static Tensor[] unpack(Tensor value, int num, int axis = 0, string name = null)
+        {
+            var _op = _op_def_lib._apply_op_helper("Unpack", name, new { value, num, axis });
+            return _op.outputs;
+        }
+
         public static Tensor where()
         {
             throw new NotImplementedException("where");
diff --git a/src/TensorFlowNET.Core/Operations/image_ops_impl.cs b/src/TensorFlowNET.Core/Operations/image_ops_impl.cs
index 6cf9f77e..b7573b92 100644
--- a/src/TensorFlowNET.Core/Operations/image_ops_impl.cs
+++ b/src/TensorFlowNET.Core/Operations/image_ops_impl.cs
@@ -129,6 +129,22 @@ namespace Tensorflow
             throw new NotImplementedException("");
         }
 
+        /// <summary>
+        /// Resize `images` to `size` using the specified `method`.
+        /// </summary>
+        /// <param name="images"></param>
+        /// <param name="size"></param>
+        /// <param name="method"></param>
+        /// <param name="align_corners"></param>
+        /// <param name="preserve_aspect_ratio"></param>
+        /// <param name="name"></param>
+        /// <returns></returns>
+        public static Tensor resize_images(Tensor images, Tensor size, ResizeMethod method = ResizeMethod.BILINEAR,
+            bool align_corners = false, bool preserve_aspect_ratio = false, string name = null)
+        {
+            throw new NotImplementedException("");
+        }
+
         /// <summary>
         /// Resize `images` to `size` using nearest neighbor interpolation.
         /// </summary>
@@ -146,4 +162,12 @@ namespace Tensorflow
                   half_pixel_centers: half_pixel_centers,
                   name: name);
     }
+
+    public enum ResizeMethod
+    {
+        BILINEAR = 0,
+        NEAREST_NEIGHBOR = 1,
+        BICUBIC = 2,
+        AREA = 3
+    }
 }
diff --git a/src/TensorFlowNET.Core/Tensors/shape_utils.cs b/src/TensorFlowNET.Core/Tensors/shape_utils.cs
new file mode 100644
index 00000000..859d931b
--- /dev/null
+++ b/src/TensorFlowNET.Core/Tensors/shape_utils.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using static Tensorflow.Binding;
+
+namespace Tensorflow
+{
+    public class shape_utils
+    {
+        public static Tensor static_or_dynamic_map_fn(Func<Tensor, Tensor> fn, Tensor elems, TF_DataType dtype = TF_DataType.DtInvalid,
+            int parallel_iterations = 32, bool back_prop = true)
+        {
+            var outputs = tf.unstack(elems).Select(arg => fn(arg)).ToArray();
+
+            throw new NotImplementedException("");
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Core/Preprocessor.cs b/src/TensorFlowNET.Models/ObjectDetection/Core/Preprocessor.cs
new file mode 100644
index 00000000..ac3cc805
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/Core/Preprocessor.cs
@@ -0,0 +1,69 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using static Tensorflow.Binding;
+
+namespace Tensorflow.Models.ObjectDetection.Core
+{
+    public class Preprocessor
+    {
+        public static Tensor[] resize_to_range(ResizeToRangeArgs args)
+        {
+            var image = args.image;
+            var min_dimension = args.min_dimension;
+            var max_dimension = args.max_dimension;
+            var method = args.method;
+            var align_corners = args.align_corners;
+
+            if (image.NDims != 3)
+                throw new ValueError("Image should be 3D tensor");
+
+            
+            Func<Tensor, Tensor> _resize_landscape_image = (image1) =>
+            {
+                return tf.image.resize_images(image1,
+                    tf.stack(new[] { min_dimension, max_dimension }),
+                    method: method,
+                        align_corners: align_corners,
+                        preserve_aspect_ratio: true);
+            };
+            Func<Tensor, Tensor> _resize_portrait_image = (image1) =>
+            {
+                return tf.image.resize_images(image1,
+                    tf.stack(new[] { min_dimension, max_dimension }),
+                    method: method,
+                        align_corners: align_corners,
+                        preserve_aspect_ratio: true);
+            };
+
+            return tf_with(tf.name_scope("ResizeToRange", values: new { image, min_dimension }), delegate
+            {
+                Tensor new_image, new_size;
+
+                if (image.TensorShape.is_fully_defined())
+                    throw new NotImplementedException("");
+                else
+                {
+                    new_image = tf.cond(
+                      tf.less(tf.shape(image)[0], tf.shape(image)[1]),
+                      () => _resize_landscape_image(image),
+                      () => _resize_portrait_image(image));
+                    new_size = tf.shape(new_image);
+                }
+
+                if (args.pad_to_max_dimension)
+                {
+                    throw new NotImplementedException("");
+                }
+
+                var result = new List<Tensor> { new_image };
+                if (args.masks != null)
+                    throw new NotImplementedException("");
+
+                result.Add(new_size);
+
+                return result.ToArray();
+            });
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Core/ResizeToRangeArgs.cs b/src/TensorFlowNET.Models/ObjectDetection/Core/ResizeToRangeArgs.cs
new file mode 100644
index 00000000..2fe799a6
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/Core/ResizeToRangeArgs.cs
@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using static Tensorflow.tensorflow.image_internal;
+
+namespace Tensorflow.Models.ObjectDetection.Core
+{
+    public class ResizeToRangeArgs
+    {
+        public Tensor image { get; set; }
+        public int[] masks { get; set; }
+        public int min_dimension { get; set; }
+        public int max_dimension { get; set; }
+        public ResizeMethod method {get;set;}
+        public bool align_corners { get; set; }
+        public bool pad_to_max_dimension { get; set; }
+        public int[] per_channel_pad_value { get; set; }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
index 083d4e4f..beb18198 100644
--- a/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
+++ b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
+using static Tensorflow.Binding;
 
 namespace Tensorflow.Models.ObjectDetection
 {
@@ -13,8 +14,23 @@ namespace Tensorflow.Models.ObjectDetection
             _args = args;
         }
 
-        public (Tensor, Tensor) preprocess(Tensor tensor)
+        /// <summary>
+        /// Feature-extractor specific preprocessing.
+        /// </summary>
+        /// <param name="inputs"></param>
+        /// <returns></returns>
+        public (Tensor, Tensor) preprocess(Tensor inputs)
         {
+            tf_with(tf.name_scope("Preprocessor"), delegate
+            {
+                /*var outputs = shape_utils.static_or_dynamic_map_fn(
+                  _image_resizer_fn,
+                  elems: inputs,
+                  dtype: new[] { tf.float32, tf.int32 },
+                  parallel_iterations: _parallel_iterations);*/
+
+            });
+
             throw new NotImplementedException("");
         }
     }