Improve Frame Rates and Thermal Resolution for High-end Thermal Cameras at once

21 Jun 2018

Users who want to solve extremely demanding measurement and testing tasks using a thermal imaging camera with cooled detectors usually face a difficult decision. Should thermograms be acquired in a FOV with a full, usually native, pixel number and the resulting high spatial resolution? Or should sequences be recorded and stored at a high frame rate with this FOV to ensure a high temporal resolution? Both at the same time is not possible, because the readout speed of the cameras limits their frame rate for a given number of pixels.

InfraTec has now resolved this balancing act and offers an entirely new level of flexibility for its high-end camera series ImageIR®. Users can choose between two speed modes for the same camera. In normal mode, the familiar frame rates are available for full, half and sub frame with the full spatial resolution. In high-speed mode, images can be taken with the identical FOV - while the frame rate increases massively.

Decrease the number of pixels, keep the FOV

The principle behind this new option is called binning. Four pixels of adjacent rows and columns are combined into one pixel. Consequently, the number of pixels of the resulting thermogram decreases. However, the FOV remains constant so that the image section captured by the camera does not change. The selected object distance and the optics used can be maintained for the respective task.

Switch once, benefit twice

Switching between both speed modes is done conveniently by software. If users want to image the smallest geometrical details, they use the native number of pixels of the camera detector. If the focus is more on the exact timing of a fast process, they resort to binning and the associated higher frame rates. The results of both scenarios can then be overlaid in a suitable manner.

The example of the ImageIR® 9400 illustrates the range resulting from the latest development of InfraTec. Usually, full-frame images with (1,280 x 1,024) IR pixels at 180 Hz can be captured with this camera. In normal mode and half-frame with (640 x 512) IR pixels this is 340 Hz. Thanks to binning, in high-speed mode the frame rate for (640 x 512) IR pixels almost doubles to 620 Hz.

High-speed mode additionally increases thermal resolution

In addition to speed, the signal-to-noise ratio improves in high-speed mode by a factor of approximately 2 due to the larger effective pixel area. This increase in thermal resolution ensures that even smaller temperature differences can be detected reliably. Thus, the quality of the images produced by means of binning meets the highest requirements.