An endoscopic probe with high resolution and multiple contrasts provides useful diagnostic information. For example, a miniature probe capable of multimodal imaging including photoacoustic imaging, optical coherence tomography (OCT), and ultrasound has been reported. However, microscale resolution is only realized in OCT modality in the probe, which may restrict the applications where high resolutions for multiple contrasts are required. Here, we present an approach to construct a miniature scanhead with 2.8 mm in diameter that achieves high-resolution multispectral photoacoustic microscopy (PAM) and OCT. The method realizes high resolution of ∼10 μm for both PAM and OCT. We experimentally demonstrate <i>ex vivo</i> and <i>in vivo</i> imaging using the scanhead.
Electric power is one of the basic requirement for socio economic and social prosperity of any country, which is mainly employs for domestic, industrial and agricultural sectors. The primary purpose of this research is to design and implement an energy meter which can remotely control and monitor through global system for mobile (GSM) communication technology. For this purpose, a single phase or three phase digital energy meters are used to add on different advanced modules. The energy meter can be activated and display power consumption information at the consumer premises on liquid crystal display and through a short message service (SMS) by using GSM technology. At the power sending end, an energy meter can be remotely control and monitor through GSM technology without any system disturbances. This study will lead to make the system easier, economical, reliable and efficient for the electrical department.
Conventionally endoscopic OCT images are reconstructed by uniform sampling in both axial and transverse direction of the image. To shorten the scanning time and reduce the acquisition data, we propose to sparsely sample the axial scans and use compressive sensing (CS) to reconstruct the full endoscopic OCT image with randomly chosen axial scans that are much less than conventional Nyquist criteria requirement. And we study the ratio of sparse sampling numerically and experimentally that are required to reconstruct acceptable OCT images. We demonstrate that the OCT image acquisition time can be significantly reduced because of much less acquired data.
We propose to use sparsely sampled line scans with a sparsity-based reconstruction method to obtain images in a wide field of view (WFOV) multifocal scanning microscope. In the WFOV microscope, we used a holographically generated irregular focus grid to scan the sample in one dimension and then reconstructed the sample image from line scans by measuring the transmission of the foci through the sample during scanning. The line scans were randomly spaced with average spacing larger than the Nyquist sampling requirement, and the image was recovered with sparsity-based reconstruction techniques. With this scheme, the acquisition data can be significantly reduced and the restriction for equally spaced foci positions can be removed, indicating simpler experimental requirement. We built a prototype system and demonstrated the effectiveness of the reconstruction by recovering microscopic images of a U.S. Air Force target and an onion skin cell microscope slide with 40, 60, and 80% missing data with respect to the Nyquist sampling requirement.
Focus-grid-based wide field-of-view microscope has been developed to break the trade-off of resolution and field of view in conventional microscopy. In the wide field-of-view microscopy, the whole sample area has to be scanned with at least Nyquist-frequency sampling for image reconstruction. We propose a novel scanning mechanism using compressive sensing (CS), where the scanning of focal spots covers only a portion of the sample. Our preliminary studies show that 75% of scanning area is enough to reconstruct a decent image. Thus we can reduce the acquisition data which allow for simpler scanning mechanism and data acquisition.