MLECO-2874: Move NMS out of the OD use_case

* Add ImageUtils
* Move image related code from UseCaseCommonUtils to ImageUtils
* Move NMS related code to ImageUtils
* Delete test specific ImageUtils and use new ImageUtils

Signed-off-by: Richard Burton <richard.burton@arm.com>
Change-Id: Icbf5dd9c6a941b0126ecdf69a0c9d9969f22729f
diff --git a/source/math/PlatformMath.cc b/source/math/PlatformMath.cc
index cc603f3..b666d29 100644
--- a/source/math/PlatformMath.cc
+++ b/source/math/PlatformMath.cc
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021 Arm Limited. All rights reserved.
+ * Copyright (c) 2021-2022 Arm Limited. All rights reserved.
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
@@ -303,6 +303,11 @@
         }
     }
 
+    float MathUtils::SigmoidF32(float x)
+    {
+        return 1.f/(1.f + std::exp(-x));
+    }
+
 } /* namespace math */
 } /* namespace app */
 } /* namespace arm */