Optical configuration of pigmented lesion detection by frequency analysis of skin speckle patterns

Abstract

Abstract:In this paper we present a novel approach of realizing a safe, simple, and inexpensive sensor applicable to pigmented lesions detection. The approach is based on temporal tracking of back-reflected secondary speckle patterns generated while illuminating the affected area with a laser and applying periodic pressure to the surface via a controlled vibration source. When applied to pigmented lesions, the technique is superior to visual examination in avoiding many false positives and resultant unnecessary biopsies. Applying a series of different vibration frequencies at the examined tissue and analyzing the 2-D time varying speckle patterns in response to the applied periodic pressure creates a unique signature for each and different pigmented lesion. Analyzing these signatures is the first step toward detection of malignant melanoma. In this paper we present preliminary experiments that show the validity of the developed sensor for the classification of pigmented lesions.

Remote photoacoustic sensing using speckle-analysis

“…This can be achieved with a more sensitive detector unit which allows the usage of low power cw-lasers. Remote vibration sensing using the speckle analysis has already been successfully demonstrated on biological tissue using low power cw-lasers 36–38 . The more sensitive detector system will also allow remote photoacoustic detection on absorbing surfaces in contrast to the only-scattering surfaces like PVCP and fat used in this work.…”

Contact‐free endoscopic photoacoustic sensing using speckle analysis

“…An avalanche photodiode array which is designed for low‐level light applications will be considered here. These two measures will decrease the needed exposure for speckle detection significantly and will allow the use of low power CW‐lasers which have already been successfully applied for remote speckle sensing . In addition, they will also enable remote photoacoustic detection on absorbing surfaces.…”

Remote Speckle-Based Measurements of Backward Brillouin Acoustic Vibrations in Optical Fibers

“…By recording the temporal speckle pattern, and by using correlation analysis of the video, we can calculate the relative shift between the frames which stands for the temporal oscillation profile. By calculating the Fourier transform of the shifts' vector, the oscillation frequencies of the captured speckle pattern can be computed [26]. The speckles analysis has already been tested successfully for several kinds of measurements such as extraction of multiple speech sources and heartbeats [27], breathing, heart rate, pulse pressure, blood Coagulation, blood oxygenation [28], alcohol concentration [29], detection of pigmented lesions, and human skin hydration [30].…”