55 citations · 122 across the 10 of their papers we have counts for
10 papers
A Four-channel Optically Pumped Magnetometer for a Magnetoencephalography Sensor Array
Joonas Iivanainen, Tony R. Carter, Jonathan E. Dhombridge +6
We present a novel four-channel OPM sensor for magnetoencephalography that utilizes a two-color pump/probe scheme on a single optical axis. We characterize its performance across 1…
A Minimum Assumption Approach to MEG Sensor Array Design
Andrey Zhdanov, Jussi Nurminen, Joonas Iivanainen +1
Objective: Our objective is to formulate the problem of the Magnetoencephalographic (MEG) sensor array design as a well-posed engineering problem of accurately measuring the neuron…
The effect of spatial sampling on the resolution of the magnetostatic inverse problem
Jussi Nurminen, Andrey Zhdanov, Wan Jin Yeo +6
In magnetoencephalography, linear minimum norm inverse methods are commonly employed when a solution with minimal a priori assumptions is desirable. These methods typically produce…
Effects of head modeling errors on the spatial frequency representation of MEG
Wan-Jin Yeo, Eric Larson, Joonas Iivanainen +5
Optically-pumped magnetometers (OPM) -- next-generation magnetoencephalography (MEG) sensors -- may be placed directly on the head, unlike the more commonly used superconducting qu…
Calibration and localization of optically pumped magnetometers using electromagnetic coils
Joonas Iivanainen, Amir Borna, Rasmus Zetter +6
In this paper, we propose a method to estimate the position, orientation and gain of a magnetic field sensor using a set of (large) electromagnetic coils. We apply the method for c…
A general method for computing thermal magnetic noise arising from thin conducting objects
Joonas Iivanainen, Antti J. Mäkinen, Rasmus Zetter +3
Thermal motion of charge carriers in a conducting object causes magnetic field noise that interferes with sensitive measurements nearby the conductor. In this paper, we describe a…
Spatial sampling of MEG and EEG revisited: From spatial-frequency spectra to model-informed sampling
Joonas Iivanainen, Antti J. Mäkinen, Rasmus Zetter +3
In this paper, we analyze spatial sampling of electro- (EEG) magnetoencephalography (MEG), where the electric or magnetic field is typically sampled on a curved surface such as the…
Magnetic-field modeling with surface currents: Physical and computational principles of bfieldtools
Antti J. Mäkinen, Rasmus Zetter, Joonas Iivanainen +3
Surface currents provide a general way to model static magnetic fields in source-free volumes. To facilitate the use of surface currents in magneto-quasistatic problems, we have im…
Magnetic-field modeling with surface currents: Implementation and usage of bfieldtools
Rasmus Zetter, Antti J. Mäkinen, Joonas Iivanainen +3
We present a novel open-source Python software package, bfieldtools, for magneto-quasistatic calculations with current densities on surfaces of arbitrary shape. The core functional…
Sampling theory for spatial field sensing: Application to electro- and magnetoencephalography
Joonas Iivanainen, Antti Mäkinen, Rasmus Zetter +3
We present a theoretical framework for analyzing spatial sampling of fields in three-dimensional space. The framework bridges Shannon's sampling and information theory to Bayesian…