Added a version of setup_hashed_features() for scan_image_boxes objects.

dlib/image_processing/setup_hashed_features.h

@@ -24,6 +24,10 @@ namespace dlib
         ): error(a) {}
     };
 
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+//                                 stuff for scan_image_pyramid
+// ----------------------------------------------------------------------------------------
 // ----------------------------------------------------------------------------------------
 
     template <
@@ -95,6 +99,79 @@ namespace dlib
         setup_hashed_features(scanner, images, fe, bits, num_samples);
     }
 
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+//                                 stuff for scan_image_boxes
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_array,
+        typename feature_extractor
+        >
+    void setup_hashed_features (
+        scan_image_boxes<hashed_feature_image<feature_extractor, projection_hash> >& scanner,
+        const image_array& images,
+        const feature_extractor& fe,
+        int bits,
+        unsigned long num_samples = 200000
+    )
+    {
+        // make sure requires clause is not broken
+        DLIB_ASSERT(0 < bits && bits <= 32 &&
+                    num_samples > 1 && 
+                    images.size() > 0,
+            "\t void setup_hashed_features()"
+            << "\n\t Invalid inputs were given to this function. "
+            << "\n\t bits:          " << bits 
+            << "\n\t num_samples:   " << num_samples 
+            << "\n\t images.size(): " << images.size() 
+            );
+
+        pyramid_disable pyr;
+
+        const random_subset_selector<typename feature_extractor::descriptor_type>& samps = 
+            randomly_sample_image_features(images, pyr, fe, num_samples);
+
+        if (samps.size() <= 1)
+            throw dlib::image_hash_construction_failure("Images too small, not able to gather enough samples to make hash");
+
+        projection_hash phash = create_random_projection_hash(samps, bits);
+
+        hashed_feature_image<feature_extractor, projection_hash> hfe;
+        hfe.set_hash(phash);
+        hfe.copy_configuration(fe);
+        scanner.copy_configuration(hfe);
+    }
+
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_array,
+        typename feature_extractor
+        >
+    void setup_hashed_features (
+        scan_image_boxes<hashed_feature_image<feature_extractor, projection_hash> >& scanner,
+        const image_array& images,
+        int bits,
+        unsigned long num_samples = 200000
+    )
+    {
+        // make sure requires clause is not broken
+        DLIB_ASSERT(0 < bits && bits <= 32 &&
+                    num_samples > 1 && 
+                    images.size() > 0,
+            "\t void setup_hashed_features()"
+            << "\n\t Invalid inputs were given to this function. "
+            << "\n\t bits:          " << bits 
+            << "\n\t num_samples:   " << num_samples 
+            << "\n\t images.size(): " << images.size() 
+            );
+
+        feature_extractor fe;
+        setup_hashed_features(scanner, images, fe, bits, num_samples);
+    }
+
 // ----------------------------------------------------------------------------------------
 
 }

dlib/image_processing/setup_hashed_features_abstract.h

@@ -85,6 +85,71 @@ namespace dlib
               feature vectors.
     !*/
 
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_array,
+        typename feature_extractor
+        >
+    void setup_hashed_features (
+        scan_image_boxes<hashed_feature_image<feature_extractor, projection_hash> >& scanner,
+        const image_array& images,
+        const feature_extractor& fe,
+        int bits,
+        unsigned long num_samples = 200000
+    );
+    /*!
+        requires
+            - 0 < bits <= 32
+            - num_samples > 1
+            - images.size() > 0
+            - it must be valid to pass images[0] into scanner.load().
+              (also, image_array must be an implementation of dlib/array/array_kernel_abstract.h)
+        ensures
+            - Creates a projection_hash suitable for hashing the feature vectors produced by
+              fe and then configures scanner to use this hash function.
+            - The hash function will map vectors into integers in the range [0, pow(2,bits))
+            - The hash function will be setup so that it hashes a random sample of num_samples
+              vectors from fe such that each bin ends up with roughly the same number of 
+              elements in it.
+        throws
+            - image_hash_construction_failure
+              This exception is thrown if there is a problem creating the projection_hash.
+              This should only happen the images are so small they contain less than 2
+              feature vectors.
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <
+        typename image_array,
+        typename feature_extractor
+        >
+    void setup_hashed_features (
+        scan_image_boxes<hashed_feature_image<feature_extractor, projection_hash> >& scanner,
+        const image_array& images,
+        int bits,
+        unsigned long num_samples = 200000
+    );
+    /*!
+        requires
+            - 0 < bits <= 32
+            - num_samples > 1
+            - images.size() > 0
+            - it must be valid to pass images[0] into scanner.load().
+              (also, image_array must be an implementation of dlib/array/array_kernel_abstract.h)
+        ensures
+            - performs: setup_hashed_features(scanner, images, feature_extractor(), bits, num_samples)
+        throws
+            - image_hash_construction_failure
+              This exception is thrown if there is a problem creating the projection_hash.
+              This should only happen the images are so small they contain less than 2
+              feature vectors.
+    !*/
+
 // ----------------------------------------------------------------------------------------
 
 }