The new imaging system was developed on the basis of the latest progress in Complementary Metal Oxide Semiconductor (CMOS) image senor technology that enabled combining Laser Speckle and Laser Doppler imaging approaches. Combining the two imaging techniques has allowed us to literally revolutionize the imaging system performance.
Principle
The system is non-contact and non-invasive. Utilizing the principle of active remote sensing, the system uses a near-IR laser light (808 nm) for illuminating the sample and array of photodetectors measuring backscattered light.
Laser light scattered by moving particles obeys a slight frequency shift (Doppler-shift) proportional to the speed of moving objects. This light forms a speckle pattern on the detector. If light is Doppler-shifted the speckle pattern is fluctuating. Measuring and analysing the signal (intensity fluctuations) from a number of different points on the object allows the user to obtain a two-dimensional map of the flow distribution in the area. The signal processing is based on Fourier and time-spatial correlation analysis of the measured signal.
Functionality
The easy handling and operating of the imager unit was one of the main goals while designing the system. The use of the imager is as simple as the use of a conventional digital photocamera. The system instantaneously displays the object placed in the imager field of view and the user just have to press a button to get a flow-image of the displayed area. The flow-image will be displayed on the screen in 1 (or 6) seconds only. All settings for the image acquisition are set automatically for the best imaging performance. Our advanced Flow-image analysis software will help you to analyse the obtained data and generate a result report.
High-speed Imaging
Parallel Signal Acquisition technology allows the system generating high-resolution images of microcirculation in real time. System uses an array of integrating photodetectors constituting a CMOS image sensor. The use of plurality of integrating photodetectors allows measuring the Doppler signal from thousands of points simultaneously substantially reducing the imaging time compared to the scanning imaging techniques. Parallel Signal Acquisition technology reduced the imaging time to only 1 second per one flow-image of 256x256 pixels size.
Statistical Image Enhancement
Statistical Image Enhancement technology provides physicians with an advanced tool
for measuring and visualizing microcirculation in a most reliable manner. This technology
provides the user with high-quality images and higher measurement accuracy.
Measuring the signal over longer times (about 6 seconds) allows laterally increase
the statistical reliability of the obtained data.
Indeed, measured perfusion signal has an essentially stochastic nature so it has
high variability especially over short times. From statistics we know, the measurement
accuracy increases as square-root of N, where N is number of sequentially obtained
flow-images. So in about 6 seconds (10 images obtained) our apparatus generates
an image which is more than 3 times more accurate compared to one image acquisition.
Visually this results in a highly detailed flow-image, which is reach of small details
hardly or not visible without the Statistical Image Enchancement technology.
Watch & Measure
Our system uses a single image sensor for both measuring the Doppler/Speckle signal and making a photographic image of the object of interest at the same time. Therefore there is direct pixel-to-pixel correspondence between those two images. This technological feature simplifies identifying the object boundaries and superimposing the flow-image on the photographic picture of the measured object thus providing a reliable visualization of the flow distribution in the area.
Since the same image sensor is used for object visualisation, the user of the imaging unit is able instantaneously monitoring the image quality in imager field of view (focusing quality, intensity distribution, imager head alignment) before geting a decision to start the imaging procedure. This substantially reduces the number of discarded flow-images and simplifies positioning of the imager head in respect to the measured object.