StixelEstimation module

Module function

The StixelEstimation module extracts columnar pixels (Stixel) from the disparity map, including the ground position, object height and depth information of each column.

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Core function analysis

1. GroundEstimation(Mat& imgDisp8)

• Function: Estimate the ground through the v-disparity method.

• Process:

• Calculate the v-disparity map.

• Use RANSAC to fit the ground line.

• Remove the ground pixels in the disparity map.

2. RmSky(Mat& imgDisp8)

• Function: Remove the pixels in the sky area and keep the valid area below the ground.

3. StixelDistanceEstimation(...)

• Function: Analyze pixels by column and generate Stixel data, including the ground height and the top position of the object.

• Data structure:

  typedef struct _stixel_t {
  int nCol;
  int nGround;
  int nHeight;
  uchar chDisparity;
  double dX, dZ;
  } stixel_t;

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Example of use

The following is the basic call of StixelEstimation:

CStixelEstimation stixelEstimator(param);
stixelEstimator.EstimateStixels(disp16);
vector<stixel_t> stixels = stixelEstimator.m_vecobjStixels;

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Notes

1. v-disparity stability: The algorithm relies on the assumption that the ground is flat, and complex terrain may affect the effect.

2. Parameter adjustment: The number of iterations and thresholds of RANSAC fitting the ground line need to be adjusted according to the data.

For more details, please refer to Main implementation details.