COMPMID-913: Fix preprocessing step for TF models.

Change-Id: If0fbb6bbe5384038124d3dc189274b8266f796ca
Reviewed-on: https://eu-gerrit-1.euhpc.arm.com/120771
Reviewed-by: Anthony Barbier <anthony.barbier@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>
Tested-by: Jenkins <bsgcomp@arm.com>

2 files changed, 88 insertions, 58 deletions

diff --git a/utils/GraphUtils.cpp b/utils/GraphUtils.cpp
index a36cf8ea9f..448343a977 100644
--- a/utils/GraphUtils.cpp
+++ b/utils/GraphUtils.cpp
@@ -36,6 +36,41 @@
 
 using namespace arm_compute::graph_utils;
 
+void TFPreproccessor::preprocess(ITensor &tensor)
+{
+    Window window;
+    window.use_tensor_dimensions(tensor.info()->tensor_shape());
+
+    execute_window_loop(window, [&](const Coordinates & id)
+    {
+        const float value                                     = *reinterpret_cast<float *>(tensor.ptr_to_element(id));
+        float       res                                       = value / 255.f;      // Normalize to [0, 1]
+        res                                                   = (res - 0.5f) * 2.f; // Map to [-1, 1]
+        *reinterpret_cast<float *>(tensor.ptr_to_element(id)) = res;
+    });
+}
+
+CaffePreproccessor::CaffePreproccessor(std::array<float, 3> mean, bool bgr)
+    : _mean(mean), _bgr(bgr)
+{
+    if(_bgr)
+    {
+        std::swap(_mean[0], _mean[2]);
+    }
+}
+
+void CaffePreproccessor::preprocess(ITensor &tensor)
+{
+    Window window;
+    window.use_tensor_dimensions(tensor.info()->tensor_shape());
+
+    execute_window_loop(window, [&](const Coordinates & id)
+    {
+        const float value                                     = *reinterpret_cast<float *>(tensor.ptr_to_element(id)) - _mean[id.z()];
+        *reinterpret_cast<float *>(tensor.ptr_to_element(id)) = value;
+    });
+}
+
 PPMWriter::PPMWriter(std::string name, unsigned int maximum)
     : _name(std::move(name)), _iterator(0), _maximum(maximum)
 {
@@ -76,28 +111,14 @@ bool DummyAccessor::access_tensor(ITensor &tensor)
     return ret;
 }
 
-PPMAccessor::PPMAccessor(std::string ppm_path, bool bgr,
-                         float mean_r, float mean_g, float mean_b,
-                         float std_r, float std_g, float std_b)
-    : _ppm_path(std::move(ppm_path)), _bgr(bgr), _mean_r(mean_r), _mean_g(mean_g), _mean_b(mean_b), _std_r(std_r), _std_g(std_g), _std_b(std_b)
+PPMAccessor::PPMAccessor(std::string ppm_path, bool bgr, std::unique_ptr<IPreprocessor> preprocessor)
+    : _ppm_path(std::move(ppm_path)), _bgr(bgr), _preprocessor(std::move(preprocessor))
 {
 }
 
 bool PPMAccessor::access_tensor(ITensor &tensor)
 {
     utils::PPMLoader ppm;
-    const float      mean[3] =
-    {
-        _bgr ? _mean_b : _mean_r,
-        _mean_g,
-        _bgr ? _mean_r : _mean_b
-    };
-    const float std[3] =
-    {
-        _bgr ? _std_b : _std_r,
-        _std_g,
-        _bgr ? _std_r : _std_b
-    };
 
     // Open PPM file
     ppm.open(_ppm_path);
@@ -108,15 +129,11 @@ bool PPMAccessor::access_tensor(ITensor &tensor)
     // Fill the tensor with the PPM content (BGR)
     ppm.fill_planar_tensor(tensor, _bgr);
 
-    // Subtract the mean value from each channel
-    Window window;
-    window.use_tensor_dimensions(tensor.info()->tensor_shape());
-
-    execute_window_loop(window, [&](const Coordinates & id)
+    // Preprocess tensor
+    if(_preprocessor)
     {
-        const float value                                     = *reinterpret_cast<float *>(tensor.ptr_to_element(id)) - mean[id.z()];
-        *reinterpret_cast<float *>(tensor.ptr_to_element(id)) = value / std[id.z()];
-    });
+        _preprocessor->preprocess(tensor);
+    }
 
     return true;
 }
diff --git a/utils/GraphUtils.h b/utils/GraphUtils.h
index b48e5b563d..cc6f40417e 100644
--- a/utils/GraphUtils.h
+++ b/utils/GraphUtils.h
@@ -29,6 +29,7 @@
 #include "arm_compute/graph/ITensorAccessor.h"
 #include "arm_compute/graph/Types.h"
 
+#include <array>
 #include <random>
 #include <string>
 #include <vector>
@@ -37,6 +38,38 @@ namespace arm_compute
 {
 namespace graph_utils
 {
+/** Preprocessor interface **/
+class IPreprocessor
+{
+public:
+    virtual ~IPreprocessor()                 = default;
+    virtual void preprocess(ITensor &tensor) = 0;
+};
+
+/** Caffe preproccessor */
+class CaffePreproccessor : public IPreprocessor
+{
+public:
+    /** Default Constructor
+     *
+     * @param mean Mean array in RGB ordering
+     * @param bgr  Boolean specifying if the preprocessing should assume BGR format
+     */
+    CaffePreproccessor(std::array<float, 3> mean = std::array<float, 3> { { 0, 0, 0 } }, bool bgr = true);
+    void preprocess(ITensor &tensor) override;
+
+private:
+    std::array<float, 3> _mean;
+    bool _bgr;
+};
+
+/** TF preproccessor */
+class TFPreproccessor : public IPreprocessor
+{
+public:
+    void preprocess(ITensor &tensor) override;
+};
+
 /** PPM writer class */
 class PPMWriter : public graph::ITensorAccessor
 {
@@ -85,18 +118,11 @@ class PPMAccessor final : public graph::ITensorAccessor
 public:
     /** Constructor
      *
-     * @param[in] ppm_path Path to PPM file
-     * @param[in] bgr      (Optional) Fill the first plane with blue channel (default = false)
-     * @param[in] mean_r   (Optional) Red mean value to be subtracted from red channel
-     * @param[in] mean_g   (Optional) Green mean value to be subtracted from green channel
-     * @param[in] mean_b   (Optional) Blue mean value to be subtracted from blue channel
-     * @param[in] std_r    (Optional) Red standard deviation value to be divided from red channel
-     * @param[in] std_g    (Optional) Green standard deviation value to be divided from green channel
-     * @param[in] std_b    (Optional) Blue standard deviation value to be divided from blue channel
+     * @param[in] ppm_path     Path to PPM file
+     * @param[in] bgr          (Optional) Fill the first plane with blue channel (default = false)
+     * @param[in] preprocessor (Optional) PPM pre-processing object
      */
-    PPMAccessor(std::string ppm_path, bool bgr = true,
-                float mean_r = 0.0f, float mean_g = 0.0f, float mean_b = 0.0f,
-                float std_r = 1.f, float std_g = 1.f, float std_b = 1.f);
+    PPMAccessor(std::string ppm_path, bool bgr = true, std::unique_ptr<IPreprocessor> preprocessor = nullptr);
     /** Allow instances of this class to be move constructed */
     PPMAccessor(PPMAccessor &&) = default;
 
@@ -104,14 +130,9 @@ public:
     bool access_tensor(ITensor &tensor) override;
 
 private:
-    const std::string _ppm_path;
-    const bool        _bgr;
-    const float       _mean_r;
-    const float       _mean_g;
-    const float       _mean_b;
-    const float       _std_r;
-    const float       _std_g;
-    const float       _std_b;
+    const std::string              _ppm_path;
+    const bool                     _bgr;
+    std::unique_ptr<IPreprocessor> _preprocessor;
 };
 
 /** Result accessor class */
@@ -226,21 +247,15 @@ inline std::unique_ptr<graph::ITensorAccessor> get_weights_accessor(const std::s
  *
  * @note If ppm_path is empty will generate a DummyAccessor else will generate a PPMAccessor
  *
- * @param[in] ppm_path Path to PPM file
- * @param[in] mean_r   Red mean value to be subtracted from red channel
- * @param[in] mean_g   Green mean value to be subtracted from green channel
- * @param[in] mean_b   Blue mean value to be subtracted from blue channel
- * @param[in] std_r    (Optional) Red standard deviation value to be divided from red channel
- * @param[in] std_g    (Optional) Green standard deviation value to be divided from green channel
- * @param[in] std_b    (Optional) Blue standard deviation value to be divided from blue channel
- * @param[in] bgr      (Optional) Fill the first plane with blue channel (default = true)
+ * @param[in] ppm_path     Path to PPM file
+ * @param[in] preprocessor Preproccessor object
+ * @param[in] bgr          (Optional) Fill the first plane with blue channel (default = true)
  *
  * @return An appropriate tensor accessor
  */
-inline std::unique_ptr<graph::ITensorAccessor> get_input_accessor(const std::string &ppm_path,
-                                                                  float mean_r = 0.f, float mean_g = 0.f, float mean_b = 0.f,
-                                                                  float std_r = 1.f, float std_g = 1.f, float std_b = 1.f,
-                                                                  bool bgr = true)
+inline std::unique_ptr<graph::ITensorAccessor> get_input_accessor(const std::string             &ppm_path,
+                                                                  std::unique_ptr<IPreprocessor> preprocessor = nullptr,
+                                                                  bool                           bgr          = true)
 {
     if(ppm_path.empty())
     {
@@ -248,9 +263,7 @@ inline std::unique_ptr<graph::ITensorAccessor> get_input_accessor(const std::str
     }
     else
     {
-        return arm_compute::support::cpp14::make_unique<PPMAccessor>(ppm_path, bgr,
-                                                                     mean_r, mean_g, mean_b,
-                                                                     std_r, std_g, std_b);
+        return arm_compute::support::cpp14::make_unique<PPMAccessor>(ppm_path, bgr, std::move(preprocessor));
     }
 }