Thermal Camera Output Data

This topic describes the output data of a thermal camera sensor.

Thermal cameras are well suited for detection in low-dimmed or hazy environments and particularly suited for pedestrian detection. This sensor produces reliable images depicting the spatial distribution of heat in shades of grey and can also produce associated temperature maps providing the temperature in kelvins for each pixel of a produced image.

Output Data

The thermal camera output can take the form of:

  • serialized protobuf binary content, produced in the shared memory and available through AVxcelerate Sensors Simulator APIs. These output data are produced by default unless Shared Memory Access is set to false in the Thermal Camera Simulation Parameters.

  • files saved to the disk when the Camera Recording format is set to PNG.
    Note: The only valid Camera Recording Format for a thermal camera is PNG. If the camera recording format is not set, or if another recording format type is set, no output will be saved to disk.

Output Types

The thermal camera outputs one or two types of results depending on how you set the simulation parameters:

  • Grayscale image

    Note: The image type produced depends on what was defined in the simulation parameters.

    Similarly to a camera simulation, the thermal camera outputs a .png image per simulation time step. However, the .png is rendered in grayscale.

    The grayscale image is an image where the only colors are shades of grey. They are particularly used in the depiction of heat maps.

    In such images, each pixel (encoded within the 0-255 range) is only meant to illustrate the temperature relationship between the objects of a given scene. Hence, the grey color scale must not be interpreted as an absolute indicator of the temperature but as a relative temperature indicator.

    Figure 1. Example of PNG file


  • Temperature Map (particularly useful in a debugging context)

    Text (*.txt) file providing the temperature of each pixel of the rendered image in kelvins.

    The values are organized as a table to effectively represent the generated image:
    • the number of lines = the image's resolution height
    • the number of values per line = the image's resolution width
    Figure 2. Example of Temperature Map


    Tip: You can convert the temperature map output into an xmp file using the Virtual Photometric Lab.
    1. The character used as decimal separator must be a dot ('.') not a comma (','), if needed replace the commas with dots.
    2. Add the following header to the *.txt file:
      3
14
2
1
-3.84	3.84	-3.072	3.072
640 512
SeparatedByLayer 1

      For more details about this header content, refer to Speos Labs User's Guide > Exporting a txt file from Virtual Photometric Lab.

    3. Import the *txt file in the Virtual Photometric Lab.
    4. Save the file as an xmp.