Active Techniques Implemented in an Introductory Signal Processing Course to Help Students Achieve Higher Levels of Learning.

Holding students to high standards and assessing, measuring and evaluating their learning with challenging, authentic problems in the midterm and final exams is the goal of the professors who teach core signal processing concepts. However, the heavy reliance of these subjects on mathematics makes it difficult for students to genuinely grasp the concepts and relate to a conceptual framework. Specifically, analyzing the signals and the functionality of systems in Fourier domain; separating the system level analysis from signal level analysis; and understanding how they are related in time domain and frequency domain are among the most challenging concepts. Students’ lower grades observed over past years in the introductory signal processing course exposed a potential disconnect between the actual level of learning and the high expectations set by the professors. In this paper, we present the active learning techniques that we implemented in one of the summer session offerings of this course in our department. The research explored Peer Instruction, pre-class reading quizzes and post-lecture quizzes. In addition to the mid and end of the quarter survey results, the comparison analysis of the grades students achieved in the active learning integrated course in the second summer session and the standard course offered in first summer session is discussed. According to our results, the developed techniques helped students in the active classroom perform significantly better than their peers participating in standard lectures when tested by challenging questions in their exams

Spectral and Spatial Light Field Encoding for Tissue Imaging, Drug Delivery and Focused Field Shaping

Optical signatures of the biological tissues and spectral characteristics of the chemotherapy agents provide distinctive information on the nature of these tissues and the chemical properties of the chemotherapy drugs delivered at the tumor sites. Equipping the tools routinely used in interventional procedures, with optical guidance could provide real-time feedback on the characteristics of the tissues and the drugs under examination by acquiring and evaluating their spectral information. A new optically guided needle system is designed here that transmits the spectrally encoded modulated light to the medium at the tip of the needle and processes the detected backscattered light to sense the presence of the blood or bile within the liver parenchyma, differentiate the benign and malignant breast tissue, activate a photocleavable prodrug and estimate the amount of the drug accumulated at the tumor site.In addition to spectral imaging of the tissues, spatially encoded light fields were used to generate images of the objects hidden within scattering materials and methods were proposed to calculate and generate the desired spatially encoded vectorial fields at the focus of high NA lenses. The results of the imaging through scattering experiments showed that utilizing the designed set of spatially encoded projection patterns significantly reduced the number of measurements required to reconstruct an image of the hidden objects. The developed reflective imaging setup is compatible with the majority of the bio-imaging settings.To generate the desired spatially encoded vectorial light fields at the image plane of the high NA lenses, a new method was proposed to calculate the required incident fields with spatially varying polarizations in the back focal plane of the lenses. With the refresh rate of 40 Hz for calculating 128128-pixel incident fields, this method could be used to update and adjust the designed focused fields in near real time. The application of this method in generating line traps for imposing translational movement on the trappedparticles was also discussed

Open Access An innovative system for 3D clinical photography in the resource-limited settings

Background: Kaposi’s sarcoma (KS) is the most frequently occurring cancer in Mozambique among men and the second most frequently occurring cancer among women. Effective therapeutic treatments for KS are poorly understood in this area. There is an unmet need to develop a simple but accurate tool for improved monitoring and diagnosis in a resource-limited setting. Standardized clinical photographs have been considered to be an essential part of the evaluation. Methods: When a therapeutic response is achieved, nodular KS often exhibits a reduction of the thickness without a change in the base area of the lesion. To evaluate the vertical space along with other characters of a KS lesion, we have created an innovative imaging system with a consumer light-field camera attached to a miniature “photography studio ” adaptor. The image file can be further processed by computational methods for quantification. Results: With this novel imaging system, each high-quality 3D image was consistently obtained with a single camera shot at bedside by minimally trained personnel. After computational processing, all-focused photos and measurable 3D parameters were obtained. More than 80 KS image sets were processed in a semi-automated fashion. Conclusions: In this proof-of-concept study, the feasibility to use a simple, low-cost and user-friendly system has been established for future clinical study to monitor KS therapeutic response. This 3D imaging system can be also applied t