Bkp Horn | Massachusetts Institute of Technology (MIT) (original) (raw)

Papers by Bkp Horn

Research paper thumbnail of A comparison of human and computer vision systems

ACM SIGART Bulletin, 1975

I will begin with a general overview of the two types of systems and compare them at a general le... more I will begin with a general overview of the two types of systems and compare them at a general level. The second section will describe the eye and camera as the input devices. Later sections will discuss segmentation of the scene, visual imagery and encoding of the scene, perception, depth and space perception, and perception of movement.

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Research paper thumbnail of Indoor Localization Using Uncooperative Wi-Fi Access Points

Sensors

Indoor localization using fine time measurement (FTM) round-trip time (RTT) with respect to coope... more Indoor localization using fine time measurement (FTM) round-trip time (RTT) with respect to cooperating Wi-Fi access points (APs) has been shown to work well and provide 1–2 m accuracy in both 2D and 3D applications. This approach depends on APs implementing the IEEE 802.11-2016 (also known as IEEE 802.11mc) Wi-Fi standard (“two-sided” RTT). Unfortunately, the penetration of this Wi-Fi protocol has been slower than anticipated, perhaps because APs tend not to be upgraded as often as other kinds of electronics, in particular in large institutions—where they would be most useful. Recently, Google released Android 12, which also supports an alternative “one-sided” RTT method that will work with legacy APs as well. This method cannot subtract out the “turn-around” time of the signal, and so, produces distance estimates that have much larger offsets than those seen with two-sided RTT—and the results are somewhat less accurate. At the same time, this method makes possible distance measure...

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Research paper thumbnail of Vision Review

This report describes research done at the Artificial Intelligence Laboratory of the Massachusett... more This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense under Office of Naval Research contract N00014-75-C-0643.MIT Artificial Intelligence Laboratory Department of Defense Advanced Research Projects Agenc

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Research paper thumbnail of Accelerated Convolutions for Efficient Multi-Scale Time to Contact Computation in Julia

Convolutions have long been regarded as fundamental to applied mathematics, physics and engineeri... more Convolutions have long been regarded as fundamental to applied mathematics, physics and engineering. Their mathematical elegance allows for common tasks such as numerical differentiation to be computed efficiently on large data sets. Efficient computation of convolutions is critical to artificial intelligence in real-time applications, like machine vision, where convolutions must be continuously and efficiently computed on tens to hundreds of kilobytes per second. In this paper, we explore how convolutions are used in fundamental machine vision applications. We present an accelerated n-dimensional convolution package in the high performance computing language, Julia, and demonstrate its efficacy in solving the time to contact problem for machine vision. Results are measured against synthetically generated videos and quantitatively assessed according to their mean squared error from the ground truth. We achieve over an order of magnitude decrease in compute time and allocated memory ...

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Research paper thumbnail of Air temperature retrieval from crowd-sourced smartphone battery temperatures for Dutch cities and its application in mesoscale model validation

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Research paper thumbnail of Extended Gaussian images

Proceedings of the IEEE, 1984

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Research paper thumbnail of Hill shading and the reflectance map

Proceedings of the IEEE, 1981

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Research paper thumbnail of Calculating the reflectance map

Applied Optics, 1979

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Research paper thumbnail of Font Forum ‘Hinting ’ of

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Research paper thumbnail of "Determining optical flow": a retrospective

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Research paper thumbnail of Eigenvectors of the Fourier Transform

It is well known that a function can be decomposed uniquely into the sum of an odd and an even fu... more It is well known that a function can be decomposed uniquely into the sum of an odd and an even function. This notion can be extended to the unique decomposition into the sum of four functions — two of which are even and two odd. These four functions are eigenvectors of the Fourier Transform with four different eigenvalues. That is, the Fourier transform of each of the four components is simply that component multiplied by the corresponding eigenvalue. Some eigenvectors of the discrete Fourier transform of particular interest find application in coding, communication and imaging. Some of the underlying mathematics goes back to the times of Carl Friedrich Gauss.

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Research paper thumbnail of Quaternions: what are they, and why do we need to know?

Acta Crystallographica Section A Foundations and Advances

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Research paper thumbnail of Machine Vision to Alert Roadside Personnel of Night Traffic Threats

IEEE Transactions on Intelligent Transportation Systems, Oct 1, 2018

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Research paper thumbnail of On the chain stability of bilateral control model

IEEE Transactions on Automatic Control

In this paper, we study the chain stability of vehicles under bilateral control (BCM), and prove ... more In this paper, we study the chain stability of vehicles under bilateral control (BCM), and prove that vehicles under bilateral control are chain stable, i.e., all input perturbations to the chain decay exponentially (with the length of the chain). Chain stability analysis tells us how vehicles under bilateral control will act in traffic when mixed with cars driven by human drivers. It shows that self-driving cars using bilateral control can reduce traffic flow instabilities in mixed traffic. Indeed, chains of BCM vehicles become perturbation-consuming dampers when inserted in traffic, since they split chains of human-driven vehicles and prevent perturbations from being transmitted from one chain of car-following cars to the next. Thus, today's traffic can be improved greatly by the insertion of BCM vehicles. The simulation results validate the theoretical analysis.

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Research paper thumbnail of On the stability analysis of mixed traffic with vehicles under car-following and bilateral control

IEEE Transactions on Automatic Control

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Research paper thumbnail of TV camera-based vehicle motion detection and its chip implementation

ABSTRACT

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Research paper thumbnail of Direct passive navigation: Analytical solution for planes

Proceedings. 1986 IEEE International Conference on Robotics and Automation, 1986

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Research paper thumbnail of Circle Generators for Display Devices-Comment

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Research paper thumbnail of David vs. Goliath?

Science News, 1986

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Research paper thumbnail of Dodo Apocrypha

Science News, 1978

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Research paper thumbnail of A comparison of human and computer vision systems

ACM SIGART Bulletin, 1975

I will begin with a general overview of the two types of systems and compare them at a general le... more I will begin with a general overview of the two types of systems and compare them at a general level. The second section will describe the eye and camera as the input devices. Later sections will discuss segmentation of the scene, visual imagery and encoding of the scene, perception, depth and space perception, and perception of movement.

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Research paper thumbnail of Indoor Localization Using Uncooperative Wi-Fi Access Points

Sensors

Indoor localization using fine time measurement (FTM) round-trip time (RTT) with respect to coope... more Indoor localization using fine time measurement (FTM) round-trip time (RTT) with respect to cooperating Wi-Fi access points (APs) has been shown to work well and provide 1–2 m accuracy in both 2D and 3D applications. This approach depends on APs implementing the IEEE 802.11-2016 (also known as IEEE 802.11mc) Wi-Fi standard (“two-sided” RTT). Unfortunately, the penetration of this Wi-Fi protocol has been slower than anticipated, perhaps because APs tend not to be upgraded as often as other kinds of electronics, in particular in large institutions—where they would be most useful. Recently, Google released Android 12, which also supports an alternative “one-sided” RTT method that will work with legacy APs as well. This method cannot subtract out the “turn-around” time of the signal, and so, produces distance estimates that have much larger offsets than those seen with two-sided RTT—and the results are somewhat less accurate. At the same time, this method makes possible distance measure...

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Research paper thumbnail of Vision Review

This report describes research done at the Artificial Intelligence Laboratory of the Massachusett... more This report describes research done at the Artificial Intelligence Laboratory of the Massachusetts Institute of Technology. Support for the laboratory's artificial intelligence research is provided in part by the Advanced Research Projects Agency of the Department of Defense under Office of Naval Research contract N00014-75-C-0643.MIT Artificial Intelligence Laboratory Department of Defense Advanced Research Projects Agenc

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Research paper thumbnail of Accelerated Convolutions for Efficient Multi-Scale Time to Contact Computation in Julia

Convolutions have long been regarded as fundamental to applied mathematics, physics and engineeri... more Convolutions have long been regarded as fundamental to applied mathematics, physics and engineering. Their mathematical elegance allows for common tasks such as numerical differentiation to be computed efficiently on large data sets. Efficient computation of convolutions is critical to artificial intelligence in real-time applications, like machine vision, where convolutions must be continuously and efficiently computed on tens to hundreds of kilobytes per second. In this paper, we explore how convolutions are used in fundamental machine vision applications. We present an accelerated n-dimensional convolution package in the high performance computing language, Julia, and demonstrate its efficacy in solving the time to contact problem for machine vision. Results are measured against synthetically generated videos and quantitatively assessed according to their mean squared error from the ground truth. We achieve over an order of magnitude decrease in compute time and allocated memory ...

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Research paper thumbnail of Air temperature retrieval from crowd-sourced smartphone battery temperatures for Dutch cities and its application in mesoscale model validation

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Research paper thumbnail of Extended Gaussian images

Proceedings of the IEEE, 1984

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Research paper thumbnail of Hill shading and the reflectance map

Proceedings of the IEEE, 1981

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Research paper thumbnail of Calculating the reflectance map

Applied Optics, 1979

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Research paper thumbnail of Font Forum ‘Hinting ’ of

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Research paper thumbnail of "Determining optical flow": a retrospective

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Research paper thumbnail of Eigenvectors of the Fourier Transform

It is well known that a function can be decomposed uniquely into the sum of an odd and an even fu... more It is well known that a function can be decomposed uniquely into the sum of an odd and an even function. This notion can be extended to the unique decomposition into the sum of four functions — two of which are even and two odd. These four functions are eigenvectors of the Fourier Transform with four different eigenvalues. That is, the Fourier transform of each of the four components is simply that component multiplied by the corresponding eigenvalue. Some eigenvectors of the discrete Fourier transform of particular interest find application in coding, communication and imaging. Some of the underlying mathematics goes back to the times of Carl Friedrich Gauss.

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Research paper thumbnail of Quaternions: what are they, and why do we need to know?

Acta Crystallographica Section A Foundations and Advances

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Research paper thumbnail of Machine Vision to Alert Roadside Personnel of Night Traffic Threats

IEEE Transactions on Intelligent Transportation Systems, Oct 1, 2018

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Research paper thumbnail of On the chain stability of bilateral control model

IEEE Transactions on Automatic Control

In this paper, we study the chain stability of vehicles under bilateral control (BCM), and prove ... more In this paper, we study the chain stability of vehicles under bilateral control (BCM), and prove that vehicles under bilateral control are chain stable, i.e., all input perturbations to the chain decay exponentially (with the length of the chain). Chain stability analysis tells us how vehicles under bilateral control will act in traffic when mixed with cars driven by human drivers. It shows that self-driving cars using bilateral control can reduce traffic flow instabilities in mixed traffic. Indeed, chains of BCM vehicles become perturbation-consuming dampers when inserted in traffic, since they split chains of human-driven vehicles and prevent perturbations from being transmitted from one chain of car-following cars to the next. Thus, today's traffic can be improved greatly by the insertion of BCM vehicles. The simulation results validate the theoretical analysis.

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Research paper thumbnail of On the stability analysis of mixed traffic with vehicles under car-following and bilateral control

IEEE Transactions on Automatic Control

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Research paper thumbnail of TV camera-based vehicle motion detection and its chip implementation

ABSTRACT

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Research paper thumbnail of Direct passive navigation: Analytical solution for planes

Proceedings. 1986 IEEE International Conference on Robotics and Automation, 1986

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Research paper thumbnail of Circle Generators for Display Devices-Comment

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Research paper thumbnail of David vs. Goliath?

Science News, 1986

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Research paper thumbnail of Dodo Apocrypha

Science News, 1978

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