Walabot API Beta
All you need to know to create a Walabot Application
Imaging Features

Walabot can provide your application with several types of imaging data. These depend primarily on two types of settings:

  • Scan profile: Defines various scanning details such as the appropriate internal antenna sets and frequencies to use.
  • Get action : Define how the image is processed and what data is provided to the application.

Scan Profiles

The following profiles are available:

  • Short-range: Short-range, penetrative scanning inside dielectric materials such as walls.
  • Profiles for distance scanning:
    • Sensor/Tracker: High-resolution images, but slower capture rate.
    • Sensor narrow: Lower-resolution images for a fast capture rate. Useful for tracking quick movement.

Get Actions

The following types of Get actions are available:

  • Raw image: Provides tridimensional (3-D) image data.
  • Raw image slice: Provides bidimensional (2-D) image data (3D image is projected to 2D plane) of the slice where the strongest signal is produced.
  • Image energy: Provides a number representing the sum of all the raw image’s pixels’ signal power.
  • Imaging targets (if the short-range scan profile was used), Sensor targets (if one of the sensor scan profiles was used), and Tracker targets (if the tracker scan profile was used): Provide a list of and the number of identified targets (in the current API version, Imaging targets provides only the single target with the strongest signal).
  • Raw Signals raw signals as recorded by the sensor. Each signal (i,j) represents the reflected pulse transmitted from antenna i, reflected from the target and received in antenna j.

Examples

Here are a few examples of applicative displays based on data provided by various profile / get combinations:

  • Raw image slice of data from short-range scanning:
    Inwall_raw
  • Raw image slice and sensor targets from sensor scanning (Object tracking):
    Sensor
  • Imaging target (pipe) from short-range scanning:
    Pipe

Dynamic Filtering

For applications that require tracking movement, Walabot can apply a dynamic-imaging filter that removes static signals, leaving only changing signals. In addition to the Moving Target Identification (MTI) filter, the Derivative filter is available for the specific frequencies typical of breathing. Here’s an example display of Derivative-filtered image energy from sensor-narrow scanning (breathing):

Breathing

Calibration and Sensitivity

Walabot calibrates scanning to ignore or reduce the signals of fixed reflectors such as walls. Additionally, for raw images (3-D and Slice), Walabot removes very weak signals according to a configurable sensitivity threshold.

Arena

Upon Get actions, Walabot processes and provides image data for a configurable, delimited space known as the arena, with configurable image resolution. If the triggered scan used the short-range profile, the arena size should have similar dimensions as Walabot, and you’ll specify it by Cartesian coordinates (ranges and resolution on the x, y, z axes); If one of the Sensor or Tracker profiles was used, the arena is usually much larger and
a Spherical coordinates system is being used (ranges and resolution along radial distance and Theta and Phi angles).

Your application can convert spherical coordinates to Cartesian ones, using the formulae:

formulae.png

For example: Sensor conversion

Coordinate Systems

For arena definitions, and in image data provided by Walabot, Cartesian (X-Y-Z) axes start from Walabot's center as the origin, and their positive directions are:

Walabot card axes

Walabot axes



When Walabot is in its plastic case, Walabot's bottom as in the above figure is at the USB connector, and the side visible in the above figure (the front) faces away from the case's Walabot logo (the logo is in the back). For spherical coordinates, radial distance (R) is from Walabot along the Z axis, and polar angle (Θ) is from the Z axis.

Walabot Polar Coordinate.png

Azimuth angle is from the X axis to orthogonal projection on the XY plane.

Units are in centimeters and degrees as relevant.

Now that you understand what Walabot can do, you can begin to design high-level application flow according to the Imaging Tasks.


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