Abstract: An apparatus for detecting a centroid of a spot produced by electromagnetic radiation, e.g., optic radiation, using an array of PIN photodiodes serving as photodetectors and being organized in columns and in rows. Vertical connections are used to interconnect the PIN photodiodes in the columns in accordance with a first pattern that interconnects two or more adjacent columns. Horizontal connections are used to interconnect PIN photodiodes in the rows in accordance with a second pattern that interconnects two or more adjacent rows. The first and second patterns of interconnections can include just two adjacent columns and two adjacent rows, respectively and form a checkerboard interconnect pattern. The interconnections are made such that there are no anode connections between the PIN photodiodes in the rows and columns.

Abstract: An apparatus for detecting a centroid of a spot produced by electromagnetic radiation, e.g., optic radiation, using an array of PIN photodiodes serving as photodetectors and being organized in columns and in rows. Vertical connections are used to interconnect the PIN photodiodes in the columns in accordance with a first pattern that interconnects two or more adjacent columns. Horizontal connections are used to interconnect PIN photodiodes in the rows in accordance with a second pattern that interconnects two or more adjacent rows. The first and second patterns of interconnections can include just two adjacent columns and two adjacent rows, respectively and form a checkerboard interconnect pattern. The interconnections are made such that there are no anode connections between the PIN photodiodes in the rows and columns.

Abstract: An apparatus for detecting a centroid of a spot produced by electromagnetic radiation, e.g., optic radiation, using an array of PIN photodiodes serving as photodetectors and being organized in columns and in rows. Vertical connections are used to interconnect the PIN photodiodes in the columns in accordance with a first pattern that interconnects two or more adjacent columns. Horizontal connections are used to interconnect PIN photodiodes in the rows in accordance with a second pattern that interconnects two or more adjacent rows. The first and second patterns of interconnections can include just two adjacent columns and two adjacent rows, respectively and form a checkerboard interconnect pattern. The interconnections are made such that there are no anode connections between the PIN photodiodes in the rows and columns.

Abstract: A hand held ultrasonic instrument is provided in a portable unit which performs both B mode and Doppler imaging. The instrument includes a transducer array mounted in a hand-held enclosure, with an integrated circuit transceiver connected to the elements of the array for the reception of echo signals. A digital signal processing circuit performs both B mode and Doppler signal processing such as filtering including wall filtering matrix and Hartley transform matrix functions, detection and Doppler estimation, as well as advanced functions such as assembly of multiple zone focused scanlines, synthetic aperture formation, depth dependent filtering, speckle reduction, flash suppression, and frame averaging. The advent of color flow imaging based on Doppler frequency estimation in medical ultrasound addresses a need for rapid assessment of overall flow characteristics in cardiac care.