Class DescribeDenseHogFastAlg<Input extends ImageBase<Input>>

java.lang.Object
boofcv.alg.feature.dense.BaseDenseHog<Input>
boofcv.alg.feature.dense.DescribeDenseHogFastAlg<Input>

public class DescribeDenseHogFastAlg<Input extends ImageBase<Input>>
extends BaseDenseHog<Input>

A variant on the original Histogram of Oriented Gradients (HOG) [1] in which spatial Gaussian weighting has been omitted, allowing for cell histograms to be computed only once. This results in about a two times speed up.

For a description of standard HOG see DescribeImageDenseHoG. Difference from standard HOG

  • No gaussian spatial weighting for each pixel inside a block
  • No bilinear interpolation between cell centers

[1] Dalal, Navneet, and Bill Triggs. "Histograms of oriented gradients for human detection." Computer Vision and Pattern Recognition, 2005. CVPR 2005.

  • Constructor Details

    • DescribeDenseHogFastAlg

      public DescribeDenseHogFastAlg​(int orientationBins, int pixelsPerCell, int cellsPerBlockX, int cellsPerBlockY, int stepBlock, ImageType<Input> imageType)
      Configures HOG descriptor computation
      Parameters:
      orientationBins - Number of bins in a cell's histogram. 9 recommended
      pixelsPerCell - Number of pixel's wide a cell is. 8 recommended
      cellsPerBlockX - Number of cells's wide a block is. 3 recommended
      cellsPerBlockY - Number of cells's wide a block is. 3 recommended
      stepBlock - Number of cells which are skipped between each block
  • Method Details

    • process

      public void process()
      Computes the descriptor across the input image
      Specified by:
      process in class BaseDenseHog<Input extends ImageBase<Input>>
    • getDescriptorsInRegion

      public void getDescriptorsInRegion​(int pixelX0, int pixelY0, int pixelX1, int pixelY1, List<TupleDesc_F64> output)
      Convenience function which returns a list of all the descriptors computed inside the specified region in the image
      Parameters:
      pixelX0 - Pixel coordinate X-axis lower extent
      pixelY0 - Pixel coordinate Y-axis lower extent
      pixelX1 - Pixel coordinate X-axis upper extent
      pixelY1 - Pixel coordinate Y-axis upper extent
      output - List of descriptions
    • getCellRows

      public int getCellRows()
    • getCellCols

      public int getCellCols()
    • getCell

      public DescribeDenseHogFastAlg.Cell getCell​(int row, int col)