title: Time-of-flight range image measurement in the presence of transverse motion using the Kalman filter

authors: Streeter, Lee

subjects: Science & Technology

abstract: Time-of-flight range imaging cameras measure distance to objects in their field of view, but are prone to error when objects move. At least three raw frames are required to obtain one range image, and the standard method is to read out raw frames into separate sets and process to find one range image per set. Motion during the acquisition of a set causes error in the corresponding range image. In this paper, the problem of motion is addressed by regarding the raw data from each pixel as a noisy time series, and using the Kalman filter to efficiently perform time-series analysis. The proposed method adapts to the effects of transverse motion, measuring a sharp range image at each raw frame. The error in the proposed method is less than the traditional approach in 80% of tests, with no detected increase in the STD due to noise. In the qualitative experimental results, the visible blur is reduced.

text: Time-of-flight range image measurement in the presence of transverse motion using the Kalman filter Time-of-flight range imaging cameras measure distance to objects in their field of view, but are prone to error when objects move. At least three raw frames are required to obtain one range image, and the standard method is to read out raw frames into separate sets and process to find one range image per set. Motion during the acquisition of a set causes error in the corresponding range image. In this paper, the problem of motion is addressed by regarding the raw data from each pixel as a noisy time series, and using the Kalman filter to efficiently perform time-series analysis. The proposed method adapts to the effects of transverse motion, measuring a sharp range image at each raw frame. The error in the proposed method is less than the traditional approach in 80% of tests, with no detected increase in the STD due to noise. In the qualitative experimental results, the visible blur is reduced.

year: 2018

title: A calculator for supporting derivation in constructive type-theory: PICTCalc

authors: Reeves, Steve

subjects: proof assistant

abstract: PICTCalc is an interactive program written in LPA Prolog which has encoded within it the rules of Martin-Löf's constructive type theory (CTT), a formal system based on the constructive or intuitionistic mathematics of Brouwer, Heyting and others. It allows us to specify and express any total, computable function, so from a computer science point of view we can write both specifications and programs, along with the derivations which lead from one to the other, in a single language. PICTCalc is a more recent version of MacPICT which is itself a reconstruction of PICT [Ham92] and is intended as a test-bed for providing formal support for work within CTT. Many of the developments and improvements were suggested by students since they used the system to work on substantial courseworks. As we shall see, PICTCalc can be used to assist in the development of derivations in CTT and so it is called a derivation assistant (DA). In this paper I show how PICTCalc can be used for supporting derivations in CTT and consider what current experience suggests for future improvement. The examples in this paper will not require any knowledge of CTT since the meaning will either be clear to anyone with experience of logic and programming notations in general or will be explained as necessary.

text: A calculator for supporting derivation in constructive type-theory: PICTCalc PICTCalc is an interactive program written in LPA Prolog which has encoded within it the rules of Martin-Löf's constructive type theory (CTT), a formal system based on the constructive or intuitionistic mathematics of Brouwer, Heyting and others. It allows us to specify and express any total, computable function, so from a computer science point of view we can write both specifications and programs, along with the derivations which lead from one to the other, in a single language. PICTCalc is a more recent version of MacPICT which is itself a reconstruction of PICT [Ham92] and is intended as a test-bed for providing formal support for work within CTT. Many of the developments and improvements were suggested by students since they used the system to work on substantial courseworks. As we shall see, PICTCalc can be used to assist in the development of derivations in CTT and so it is called a derivation assistant (DA). In this paper I show how PICTCalc can be used for supporting derivations in CTT and consider what current experience suggests for future improvement. The examples in this paper will not require any knowledge of CTT since the meaning will either be clear to anyone with experience of logic and programming notations in general or will be explained as necessary.

year: 1994-06

title: Whaikoorero: a study of formal Maori speech

authors: Mahuta, Robert Te Kotahi

subjects: Whaikoorero

abstract: Whaikoorero is regarded as the traditionally valued mode of communication. It is the language of the marae, the language of the chiefs and elders, and the only acceptable form of public statement in the Maori world. At the same time it is an artistic form, difficult to master, and demanding long years of practice and experience.
It is true, as I have pointed out, that one can read and listen to the myths and traditions of the Maori in books, on tapes, and through radio broadcasts. Yet it is the public rendering, the synthesising of myth and tradition, the living and the dead, and the interweaving of topical matters with the beliefs and values of the society, which hold the greatest interest for the Maori. For in whaikoorero history is relived, man reaffirmed, and status gained. The dead are recalled to participate with the living in social gatherings where tradition is orally transmitted, reaffirmed and relived. These then are some of the reasons why whaikoorero persists as a literary form and as a social feature within contemporary Maori society.

text: Whaikoorero: a study of formal Maori speech Whaikoorero is regarded as the traditionally valued mode of communication. It is the language of the marae, the language of the chiefs and elders, and the only acceptable form of public statement in the Maori world. At the same time it is an artistic form, difficult to master, and demanding long years of practice and experience.
It is true, as I have pointed out, that one can read and listen to the myths and traditions of the Maori in books, on tapes, and through radio broadcasts. Yet it is the public rendering, the synthesising of myth and tradition, the living and the dead, and the interweaving of topical matters with the beliefs and values of the society, which hold the greatest interest for the Maori. For in whaikoorero history is relived, man reaffirmed, and status gained. The dead are recalled to participate with the living in social gatherings where tradition is orally transmitted, reaffirmed and relived. These then are some of the reasons why whaikoorero persists as a literary form and as a social feature within contemporary Maori society.

year: 1974