Measuring temperatures

Note

The temperature measurement functionality is available for radiometric cameras.

Basic steps to temperature measurements

  • Adjust the camera focus. This is very important for a correct temperature measurement.

  • Select a temperature range that matches the expected temperature of the object you are inspecting.

  • Adjusting the temperature scale can make it possible to detect anomalies and smaller temperature differences in the part of the image of interest.

  • For accurate temperature measurements, it is important to set the measurement parameters.

Measurement tools

To measure a temperature, you can use one or more measurement tools, e.g., a spot or a box.

  1. Alarm

  2. Result table

  3. Box

  4. Spot

  5. Temperature scale

Add and remove a tool

On the main toolbar, select Measurement. This displays a toolbar, where you can do the following:

  • Remove all tools.

  • Add a center spot.

  • Add a hot spot detection within a box area.

  • Add a cold spot detection within a box area.

  • Add a user preset.

Edit a user preset

A user preset is a measurement tool, or a group of measurement tools, with predefined characteristics.

To edit a user preset, do the following:

  1. On the main toolbar, select Measurement.

  2. Select User preset. Push and hold, by using the joystick or tapping the screen. This displays a toolbar.

  3. Select Add measurement. This displays a toolbar, where you can do the following:

    • Add a spot.

    • Add a box.

    • Add a circle.

    • Add a line.

    • Set up a differential calculation (delta).

      Note

      Before you can set up a difference calculation, you must first add at least one measurement tool.

  4. The added tool is displayed with one or more handles.

  5. Push the joystick or tap the menu button. This displays a toolbar, where you can do the following (depending on the type of tool):

  6. When all measurement tools have been added, select Save as user preset.

Move and resize a tool

Note

Any changes of position and size of the current tool will be lost if you select another measurement tool. If you wish to keep the position and size settings, use the user preset feature. See section Edit a user preset.

Move a spot

  1. Activate edit mode by tapping the spot on the screen. The spot is now displayed with a handle.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. On the toolbar, do one or more of the following:

    1. Select Move and push the joystick. Move the joystick up/down and left/right to move the tool.

      You can also tap and drag the spot.

    2. Select Center to center the spot on the screen.

    3. To exit edit mode, do one of the following:

      • Push the joystick and select Done.

      • Tap the screen outside the tool.

Move and resize a box, circle, or line tool

  1. Activate edit mode by tapping the tool on the screen. The tool is now displayed with one or more handles.

    Note

    For the box tool, tap one of the corners.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. Select Move/resize. This displays a toolbar, where you can do one or more of the following:

    • Select Resize and push the joystick. Move the joystick up/down and left/right to resize the tool.

      You can also tap and hold one of the outer handles and drag the handle to resize the tool.

    • Select Move and push the joystick. Move the joystick up/down and left/right to move the tool.

      You can also tap the middle handle and drag to move the tool.

    • Select Center to center the box or circle tool on the screen.

    • Select Rotate & center line to rotate and center the line tool.

  4. To exit edit mode, do one of the following:

    • Push the joystick and select Done.

    • Tap the screen outside the tool.

Display values in the result table

For the box, circle, and line tools, you can set the camera to display the maximum, minimum, and average values in the result table.

To display values in the result table, do the following:

  1. Activate edit mode by tapping the tool on the screen. The tool is now displayed with one or more handles.

    Note

    For the box tool, tap one of the corners.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. Select Max/Min/Avg. This displays a toolbar, where you can do one or more of the following:

    • Display the maximum value.

    • Display the minimum value.

    • Display the average value.

    • Display the maximum and minimum markers (hot/cold spots).

  4. Push the joystick or tap the button to toggle the function between inactive and active.

  5. When completed, do one of the following:

    • Push the Back button. On the toolbar, select Done.

    • Tap the screen outside the tool.

Display a graph

For the line tool, you can set the camera to display a graph.

To display a graph, do the following:

  1. Select the line tool by tapping the tool on the screen. The tool is now displayed with one or more handles.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. Select Graph/Max/Min/Avg and then select Graph.

  4. Push the joystick or tap the button to toggle the function between inactive and active.

  5. When completed, do one of the following:

    • Push the Back button. On the toolbar, select Done.

    • Tap the screen outside the tool.

Set up a difference calculation

A difference calculation gives the difference (delta) between two measurement results. You can also set up a difference calculation for a measurement result and a fixed temperature.

You can set up a difference calculation when previewing an image, when defining user presets, or when editing an image in the archive.

Note

Before you can set up a difference calculation, you must first add at least one measurement tool.

To set up a difference calculation, do the following:

  1. If you are defining user presets, select Add measurement. This displays a toolbar.

  2. If you are in edit mode in the Gallery, do the following:

    1. Push the joystick or tap the screen. This displays a toolbar.

    2. Select Measurement. This displays a toolbar.

  3. On the toolbar, select Add delta. This displays a dialog box where you can select the measurement tools that you want to use in the difference calculation. You can also select a fixed-temperature reference.

  4. To close the dialog box, push the Back button.

Set up a measurement alarm

You can make the camera trigger an alarm when certain measurement conditions are met.

The camera supports the following types of alarm:

  • Above: Triggers an alarm when the temperature is above the preset alarm temperature.

  • Below: Triggers an alarm when the temperature is below the preset alarm temperature.

Set up an alarm for a spot, box, circle, or line tool

Note

Before you can set up an alarm for a box, circle, or line tool, you must first set the camera to display at least one value (maximum, minimum, or average) in the result table. For more information, see section Display values in the result table.

To set an alarm, do the following:

  1. Select the tool by tapping the tool on the screen. The tool is now displayed with one or more handles.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. On the toolbar, select Set alarm. This displays a dialog box.

  4. In the dialog box, you can define the settings for the alarm.

    • Alarm condition: The condition that triggers the alarm (Above or Below). Select Off to deactivate the alarm.

    • Select measurement: Available options are the values you have previously defined for the tool (Max, Min, and/or Avg).

    • Alarm limit: The temperature value that will be the critical condition when an alarm is triggered or not.

  5. To close the dialog box, push the Back button.

  6. To exit edit mode, do one of the following:

    • Push the joystick and select Done.

    • Tap the screen outside the tool.

Set up an alarm for a difference calculation

You can set up an alarm for a difference calculation when defining user presets, or when editing an image in the archive.

To set up an alarm for a difference calculation, do the following:

  1. If you are in edit mode in the Gallery, do the following:

    1. Push the joystick or tap the screen. This displays a toolbar.

    2. Select Measurement. This displays a toolbar.

  2. On the toolbar, select Select > Delta. This displays a toolbar.

  3. Select Set alarm on delta. This displays a dialog box.

  4. In the dialog box, you can define the settings for the alarm.

    • Alarm condition: The condition that triggers the alarm (Above or Below). Select Off to deactivate the alarm.

    • Alarm limit: The temperature value that will be the critical condition when an alarm is triggered or not.

  5. To close the dialog box, push the Back button.

Temperature range

The camera is calibrated for different temperature ranges. The available temperature range options depend on the camera model.

For accurate temperature measurements, you must select a temperature range that matches the expected temperature of the object you are inspecting.

To change the temperature range, do one of the following:

  • Push the Temperature range button and then select a temperature range by using the joystick or touching the screen. See also section Temperature range.

  • On the Settings menu, select Camera temperature range. This displays a menu where you can select the temperature range.

Measurement parameters

For very accurate measurements, it is important to set the measurement parameters.

Note

During normal operation there is typically no need to change the default measurement parameters, see section Recommended values.

Types of parameters

The camera can use these measurement parameters:

  • External IR window compensation, i.e., the temperature of any protective windows, protective shields, etc., that are set up between the camera and the object of interest. If no protective window is used, this value is irrelevant and should be left inactive.

  • Object distance, i.e., the distance between the camera and the object of interest.

  • Atmospheric temperature, i.e., the temperature of the air between the camera and the object of interest.

  • Relative humidity, i.e., the relative humidity of the air between the camera and the object of interest.

  • Reflected temperature, which is used when compensating for the radiation from the surroundings reflected by the object into the camera. This property of the object is called “reflectivity.”

  • Emissivity, i.e., how much radiation an object emits, compared with the radiation of a theoretical reference object at the same temperature (called a “blackbody”). The opposite of emissivity is reflectivity. The emissivity determines how much of the radiation originates from the object as opposed to being reflected by it.

    Note

    There is an Emissivity mode setting, which you can use to enter the emissivity by material instead of by value. Select Settings > Device settings > User interface options > Emissivity mode > Select from materials table.

Emissivity is the most important measurement parameter to set correctly. If the Emissivity is set to a low value, the Reflected temperature also becomes important. The parameters Object distance, Atmospheric temperature, and Relative humidity are relevant for longer distances. The External IR window compensation must be activated if a protective window is used.

Set the measurement parameters

You can set the measurement parameters globally. You can also change the Emissivity, Reflected temperature, and Object distance parameters locally for a measurement tool.

Local parameters are normally only effective for a fixed setup, where each measurement tool is set for a specific object of interest. For a general handheld application, the global parameters are usually sufficient.

Note

  • Emissivity and Reflected temperature are the two most important measurement parameters to set correctly in the camera.

  • If you change the Emissivity, monitor the temperature range and make sure it remains appropriate.

Set global parameters

  1. Push the joystick or tap the menu button. This displays the main toolbar.

  2. Select Measurement parameters. This displays a toolbar.

  3. On the toolbar, select a parameter. This displays a dialog box, where you can change the parameter value.

  4. To close the dialog box, push the Back button.

Change local parameters

You can change the local parameters for a measurement tool.

A P next to the measurement tool on the screen indicates that local parameters have been activated for the tool.

  1. Select the tool by tapping the tool on the screen. The tool is now displayed with one or more handles.

  2. Push the joystick or tap the menu button. This displays a toolbar.

  3. Select Use local parameters.

  4. Push the joystick or tap the button to activate the use of local parameters. This displays a toolbar.

  5. On the toolbar, select a parameter. This displays a dialog box, where you can change the parameter value.

  6. To close the dialog box, push the Back button.

  7. To exit edit mode, do one of the following:

    • Push the joystick and select Done.

    • Tap the screen outside the tool.

Note

When you select another measurement tool, the local parameters are reset. If you wish to keep the local parameter settings, use the user preset feature. See section Edit a user preset.

Color alarms and isotherms

By using color alarms (isotherms), anomalies can easily be discovered in an infrared image. The isotherm command applies a contrasting color to all pixels with a temperature above, below, or between the set temperature levels.

The camera also features isotherm types that are specific to the building trade:

  • Condensation alarm: Detects areas with potential moisture problems. The alarm will trigger when the relative humidity is above a preset value.

  • Insulation alarm: Detects areas where there may be an insulation deficiency in the building. The alarm will trigger when the insulation level is below a preset value of the energy leakage through a wall.

Above alarm: Highlights all pixels with a temperature above the specified temperature level.

Below alarm: Highlights all pixels with a temperature below the specified temperature level.

Interval alarm: Highlights all pixels with a temperature between two specified temperature levels.

Condensation alarm: Highlights areas with potential moisture problems.

Insulation alarm: Highlights areas where there may be an insulation deficiency in a building.

Set up a color alarm

To set up a color alarm, do the following:

  1. Push the joystick or tap the menu button. This displays the main toolbar.

  2. Select Color. This displays a toolbar.

  3. On the toolbar, select a color alarm. This displays a dialog box where you can define the settings for the alarm.

    Settings for the Above alarm and Below alarm:

    • Temperature limit

    • Palette

    Settings for the Interval alarm:

    • Low temperature

    • High temperature

    • Palette

    Settings for the Condensation alarm:

    • Atmospheric temperature: The current atmospheric temperature.

    • Relative humidity: The current relative humidity.

    • Relative humidity limit: The relative humidity level at which you want the alarm to be triggered. A relative humidity of 100% means that water vapor condenses from the air as liquid water (= dewpoint). A relative humidity of about 70% or above can cause mold.

    Settings for the Insulation alarm:

    • Indoor temperature: The current indoor temperature.

    • Outdoor temperature: The current outdoor temperature.

    • Thermal index: The insulation level (an integer between 0 and 100).

  4. To close the dialog box, push the Back button.