@spec bowImgDescriptorExtractor(Evision.Feature2D.t(), Evision.DescriptorMatcher.t()) ::
  t() | {:error, String.t()}

The constructor.

Positional Arguments

• dextractor: Evision.Feature2D.

  Descriptor extractor that is used to compute descriptors for an input image and its keypoints.

• dmatcher: Evision.DescriptorMatcher.

  Descriptor matcher that is used to find the nearest word of the trained vocabulary for each keypoint descriptor of the image.

Return

• self: Evision.BOWImgDescriptorExtractor.t()

Python prototype (for reference only):

BOWImgDescriptorExtractor(dextractor, dmatcher) -> <BOWImgDescriptorExtractor object>

@spec compute(t(), Evision.Mat.maybe_mat_in(), [Evision.KeyPoint.t()]) ::
  Evision.Mat.t() | {:error, String.t()}

compute

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()
• image: Evision.Mat
• keypoints: [Evision.KeyPoint]

Return

• imgDescriptor: Evision.Mat.t().

  Computed output image descriptor.

Has overloading in C++

Python prototype (for reference only):

compute(image, keypoints[, imgDescriptor]) -> imgDescriptor

@spec compute(
  t(),
  Evision.Mat.maybe_mat_in(),
  [Evision.KeyPoint.t()],
  [{atom(), term()}, ...] | nil
) ::
  Evision.Mat.t() | {:error, String.t()}

compute

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()
• image: Evision.Mat
• keypoints: [Evision.KeyPoint]

Return

• imgDescriptor: Evision.Mat.t().

  Computed output image descriptor.

Has overloading in C++

Python prototype (for reference only):

compute(image, keypoints[, imgDescriptor]) -> imgDescriptor

@spec descriptorSize(Keyword.t()) :: any() | {:error, String.t()}

@spec descriptorSize(t()) :: integer() | {:error, String.t()}

Returns an image descriptor size if the vocabulary is set. Otherwise, it returns 0.

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()

Return

• retval: integer()

Python prototype (for reference only):

descriptorSize() -> retval

@spec descriptorType(Keyword.t()) :: any() | {:error, String.t()}

@spec descriptorType(t()) :: integer() | {:error, String.t()}

Returns an image descriptor type.

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()

Return

• retval: integer()

Python prototype (for reference only):

descriptorType() -> retval

@spec getVocabulary(Keyword.t()) :: any() | {:error, String.t()}

@spec getVocabulary(t()) :: Evision.Mat.t() | {:error, String.t()}

Returns the set vocabulary.

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()

Return

• retval: Evision.Mat.t()

Python prototype (for reference only):

getVocabulary() -> retval

@spec setVocabulary(t(), Evision.Mat.maybe_mat_in()) :: t() | {:error, String.t()}

Sets a visual vocabulary.

Positional Arguments

• self: Evision.BOWImgDescriptorExtractor.t()

• vocabulary: Evision.Mat.

  Vocabulary (can be trained using the inheritor of BOWTrainer ). Each row of the vocabulary is a visual word (cluster center).

Python prototype (for reference only):

setVocabulary(vocabulary) -> None