Increasing the Geomet­rical Resol­u­tion with Micro­Scan

One of the key innovations of the high-end camera series ImageIR® and VarioCAM® High Definition is MicroScan. With the help of this function the number of pixels being used can be quadrupled compared to the native number of pixels of the FPA detector being used. This allows thermography of significantly higher image quality. Users can apply infrared cameras to produce thermograms with geometrical resolutions up to (2.560 x 2.048) IR pixels. Such recordings show measurement objects with a superb image quality.

InfraTec Glossary MicroScan - Thermal image hand with magnifier
0 | 2

The Following will be Achieved by Micro­Scan

Depending on the point of view, MicroScan has the following effects:

It...

  • quadruples the number of pixels

  • doubles the spatial sampling rate and thus the (spatial) Nyquist frequency of the measurement system

  • divides the pixel grid in half

  • reduces aliasing artefacts

  • increases the quality of the images

The practical significance of the difference between the use of the native detector format of an infrared camera and the image format obtained using MicroScan can best be depicted visually. The following comparison shows the images of a Siemens star – one without and one with the MicroScan function activated. In each of the two figures two red, circular markings are shown. Inside the large circle, the frequency of the Siemens star's rays exceeds the Nyquist frequency of the detector. The smaller circle encloses the part of the Siemens-star in which the ray’s frequency exceeds the Nyquist frequency with MicroScan. For reasons of mechanical stabilization, however, the Siemens star here no longer has a ray structure, but is compact.

InfraTec Glossary MicroScan - Aliasing
Figure of the Siemens star without activated MicroScan function
InfraTec Glossary MicroScan - Aliasing
Figure of the Siemens star with activated MicroScan function – quadrupling the number of pixels and reducing the pixel grid by half

Aliasing and Nyquist Frequency

This example of the Siemens-star reveals the significant improvement in image quality with MicroScan. The sampling frequency of the infrared camera results from the reciprocal of the so-called pixel pitch, which is the distance between the centre of two neighbouring pixels. These are effects, which cannot be eliminated by the application of software-based filters. Aliasing occurs if the sampling rate of a measuring instrument is lower than half of the frequency of the measured signal. This frequency is called Nyquist frequency:

ƒnyquist = ½ · ƒsampling

In our application, however, this is not a temporal frequency, which is expressed in Hz, but spatial frequencies with the unit m-1 (1 / meter). The sampling frequency of the thermographic camera results from the reciprocal of the so-called pixel pitch, which is the distance between the centre of two neighbouring pixels. Assuming that this pixel pitch of a thermogram corresponds to a distance of 2 mm on the measurement object, the Nyquist frequency would be 1/2 * 1/(2 mm) = 0,25 mm-1. Structures in the object that have a periodicity < 4 mm therefore generate aliasing artefacts. Thus, the sampling frequency at which the original signal is measured, has to be more than twice as high as the highest frequency contained in the original signal ƒsignal:

ƒsampling > 2 · ƒsignal

This is How Micro­Scan Works with the Camera Series ImageIR®

In the models of the camera series ImageIR®, a fast-rotating MicroScan wheel integrated in the infrared camera ensures the practical implementation of MicroScan. Four plane-parallel windows permeable to infrared are integrated in the filter wheel, each tilted by a precisely defined angle. The tilting causes the image on the detector to be displaced laterally by half a pixel pitch for each window. These individual images are merged in real time to form a thermogram with four times the number of pixels. Each pixel in the image represents a real temperature measurement value and not an interpolated pixel.

InfraTec Glossary MicroScan comparison

This is not only very precise, but also very fast. How fast can be demonstrated on the example of the ImageIR® 8300 hp. If the infrared camera runs with (640 x 512) IR pixels in full frame mode at its maximum frame rate, the MicroScan wheel spins at more than 5.000 rotations per minute. Due to such high speeds, users applying MicroScan can thermographically analyze processes with fast moving targets or rapidly changing temperatures. Therefore, this technology is predestined not only for use in microthermography, but also for a wide variety of security applications.

This is How Micro­Scan Works with the Camera Series Vari­oCAM® High Defin­i­tion

In the VarioCAM® High Definition camera series the MicroScan function is implemented via a tilted germanium disc positioned between the IR detector and the optics.

The disk rotates and deflects the beam path for all pixels of the sensor matrix. Four individual images, taken every quarter turn of the disk, are then combined to form a high-resolution thermal image. The offset between images is precisely defined, so that the distances between the pixels are fully filled. The fill factor, which describes the relationship between the sensitive cell and the insulation, increases to 100%. This results in a complete image of the measurement object.

InfraTec Glossary MicroScan - VarioCAM HD head with notebook

Infrared Cameras from InfraTec with Micro­Scan Func­tion

Infrared cameras

Users of the Micro­Scan Func­tion Benefit from The Following Advant­ages

In the everyday use of thermographic cameras, MicroScan proves itself particularly through an obvious quality gain with regard to the recognisability of details. The images show the objects to be measured in extremely high resolution. This is illustrated by a glance at the edges and structures of the objects: Even oblique object edges or curves are exactly reproduced by digital zoom. The use of MicroScan simplifies the evaluation and analysis in the field of thermography for users because significantly more details can be easily recognized in the images. The MicroScan function is suitable for continuous operation and can be used without time restrictions.

Usage of Micro­Scan Func­tion

Relevant Indus­tries & Applic­a­tions

thermal imaging in electronics

Elec­tronics & Elec­trical Engin­eering

Measure temperature distributions of smallest electronic components with infrared cameras.

thermal imaging for environmental studies

Envir­on­mental Studies

Look for smallest temperature differences in landscapes, biotopes and labs using infrared camera models of highest measurement precision.

microthermography

Micro-Ther­mo­graphy

Micro-thermography allows for the thermal analysis of smallest structures in the micrometer range, providing a detailed representation of the temperature distribution on complex electronic assemblies.

All branches and application areas
Contact to thermography division of InfraTec

Would You Like to Know More?

It is not unusual for tasks to be associated with special requirements. Discuss your specific application needs with our specialists, receive further technical information or learn more about our additional services.

United Kingdom & Irland
InfraTec GmbH Infrarotsensorik und MesstechnikGostritzer Straße 61 - 6301217 DresdenGERMANY

Further Glossary Items relating to MicroScan

InfraTec thermography - Feature EverSharp

Ever­Sharp Func­tion

With the innovative EverSharp function all objects of the image scene are displayed sharply, not depending on camera distance or lens. With the help of special algorithms thermal images with different focus positions are combined automatically, so that only the sharp object structures are displayed in the resulting thermal image. Thus, thermal images turn out very impressive as all objects are displayed in superb image quality.

InfraTec thermography - High-speed Mode

High-speed Mode – Increase Frame Rate and Sens­it­ivity

Due to the binning technology, infrared cameras have two speed modes – the standard mode and the high-speed mode, in which the frame rate increases more than three times. The field of view remains constant in both modes, so the scene captured by the camera does not change. In high-speed mode, the thermal resolution also increases by a factor of two.

HighSense for thermographic camera series ImageIR®

High­Sense – Always the Optimal Camera Setting

Thanks to HighSense, ImageIR® users have the option of setting up individual measuring ranges based on the factory calibration that best suit the respective task. Depending on the measuring task, the required temperature range can be selected and the optimum integration time for this purpose is calculated – or one decides to proceed in reverse order. Thus, the calibration can be retained even in the case of changed integration times.

Thermography with ImageIR series - HDR feature - Picture credits: © iStock.com / Vershinin M

HDR – Simultaneous Mapping of Wide Temperature Ranges

The High Dynamic Range (HDR) function of the Infrared ImageIR® camera series enables measurement scenarios with extremely different temperatures to be recorded continuously. When recording in HDR mode, multiple thermograms with different integration times and different filters are recorded quickly in succession and compiled into an overall image with a high dynamic range. The measuring range can span up to 1,500 K. Users obtain high-contrast images in a wide temperature range characterized by high measurement accuracy.

Significantly extended temperature range using the MIT function

Multi Integration Time (MIT)

To measure temperatures spanning more than one calibration range requires the acquisition of multiple thermograms with different calibrations. This can be achieved by using our Multi Integration Time feature (MIT). This function increases the dynamic range up to 16 bit and significantly extends the temperature measurement ranges.

Thermal image during ignition of an airbag  Image Small

Window Mode (Subwin­dowing) – Capture of Rapid Sequences

The thermal imaging camera can be operated in full, half, quarter and sub mode. With the camera control software, it is possible to use the extended subwindowing function. Using click-and-drag, freely definable sections can be set up quickly and conveniently. A defined sub-frame of the detector is picked out to achieve these extremely high refresh rates.

Thermografie-Kameraserie ImageIR® mit neuer 10 GigE-Schnittstelle

10 GigE Inter­face for a Strong Increase in Output

The 10 Gigabit Ethernet interface of the high-end camera series ImageIR® opens this extremely fast transmission standard with a NIC specially developed by InfraTec. This works with optical or electrical transceiver modules that are easy to change and are called SFP+.

Thermography Cameras using Micro­Scan*

InfraTec Infrared camera
High-end Cameras

ImageIR® 8300 hp

Image Format(1,280 x 1,024) IR-Pixel
Detector typeMCT or InSb

InfraTec Infrared camera
High-end Cameras

ImageIR® 8800

Image Format(1,280 x 1,024) IR-Pixel
Detector typeMCT

InfraTec Infrared camera
High-end Cameras

ImageIR® 9400

Image Format(2,560 x 2,048) IR-Pixel
Detector typeInSb

InfraTec Infrared camera
High-end Cameras

ImageIR® 9400 hp

Image Format(2,560 x 2,048) IR-Pixel
Detector typeInSb

InfraTec Infrared camera
High-end Cameras

ImageIR® 9500

Image Format(2,560 x 1,440) IR-Pixel
Detector typeMCT

InfraTec Infrared camera
System Cameras

VarioCAM® HD head 900 security

Image Format(2,048 x 1,536) IR-Pixel
Detector typeUncooled Microbolometer Focal Plane Array

InfraTec Infrared camera
System Cameras

VarioCAM® HD head 900

Image Format(2,048 x 1,536) IR-Pixel
Detector typeUncooled Microbolometer Focal Plane Array