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You searched for subject:(spectral luminous efficiency). Showing records 1 – 3 of 3 total matches.

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1. Eloholma, Marjukka. Development of Visual Performance Based Mesopic Photometry.

Degree: 2005, Helsinki University of Technology

This work started by investigating the applicability of the photopic V(λ) function to predict visual task performance at mesopic light levels. Visual acuity and pedestrian visibility experiments were carried out in varied lighting and viewing conditions. The results indicated the inadequacy of photopic photometry to characterise the response of peripheral vision at low mesopic light levels. They also indicated that mesopic spectral sensitivity is visual task dependent. Based on these findings, and on an extensive review of mesopic research work, it was evident that there was a demand for visual performance based mesopic photometry. In order to establish a basis for mesopic photometry, a European research consortium with multi-disciplinary expertise was formed. Following this, a framework for the development of performance based mesopic photometry was developed. With this framework the international lighting community and EC Fifth Framework Programme were convinced to identify the urgent need for mesopic photometry. The work continues by introducing a multi-technique approach developed and adopted in a European research work MOVE. In the work of MOVE, a large data-base of mesopic visual task performance was generated by investigating the visual performance of night-time driving using three visual sub-tasks. The data was used in modelling mesopic spectral sensitivity. The MOVE work resulted in two distinct mesopic models; a practical (i.e. linear) model and a more complex chromatic model. The practical model is applicable for the visual task of night-time driving in situations where the background and target both have fairly broad spectral power distributions. The chromatic model gives a better prediction of performance for tasks which colourfulness (chromatic saturation) is high. The MOVE practical model was applied in road lighting dimensioning via road luminance measurements. Road lighting installations using HPS and MH lamps were measured with a CCD luminance photometer. Analysis of the applicability of the MOVE model is conducted on the basis of luminance measurements, calculations and on comparison to a recently proposed X-model by Rea et al. The work concludes by describing how the new performance-based mesopic models of MOVE are integrated into the CIE (Commission Internationale de l'Eclairage) work in order to contribute to the establishment of a standard for mesopic photometry. Finally, the impacts of standardisation of mesopic photometry on lighting dimensioning and products are discussed.

Report / Helsinki University of Technology, Lighting Laboratory, ISSN 1795-9039; 36

Advisors/Committee Members: Helsinki University of Technology, Department of Electrical and Communications Engineering, Lighting Laboratory.

Subjects/Keywords: mesopic; photometry; visual performance; luminance; spectral luminous efficiency

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Eloholma, M. (2005). Development of Visual Performance Based Mesopic Photometry. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2005/isbn9512278685/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Eloholma, Marjukka. “Development of Visual Performance Based Mesopic Photometry.” 2005. Thesis, Helsinki University of Technology. Accessed July 15, 2019. http://lib.tkk.fi/Diss/2005/isbn9512278685/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Eloholma, Marjukka. “Development of Visual Performance Based Mesopic Photometry.” 2005. Web. 15 Jul 2019.

Vancouver:

Eloholma M. Development of Visual Performance Based Mesopic Photometry. [Internet] [Thesis]. Helsinki University of Technology; 2005. [cited 2019 Jul 15]. Available from: http://lib.tkk.fi/Diss/2005/isbn9512278685/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Eloholma M. Development of Visual Performance Based Mesopic Photometry. [Thesis]. Helsinki University of Technology; 2005. Available from: http://lib.tkk.fi/Diss/2005/isbn9512278685/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

2. Orreveteläinen, Pasi. Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels.

Degree: 2005, Helsinki University of Technology

The aim of this work was to find out how the spectral sensitivity of the human eye varies in peripheral vision at mesopic and low photopic luminance levels. Two different measurement methods were employed for this purpose. Reaction time and contrast threshold measurements were conducted at various mesopic and low photopic luminance levels in foveal and peripheral vision. Luminance levels between 0.1 cd/m2 and 20 cd/m2 and visual target eccentricities of 0°, 10°, 30° and 60° were investigated in the measurements. Both measurement methods revealed the same observations: at low photopic luminance levels, the currently used V(λ) function is not the best descriptive spectral luminous efficiency function for peripheral vision. The short wavelengths were underestimated by the V(λ) function. A new spectral luminous efficiency function Vper(λ) was developed for peripheral vision at photopic light levels. This function is a linear combination of V(λ) and V10(λ) functions and takes into account the higher spectral sensitivity to short wavelengths as compared to the V(λ) function. Both measurement methods show that this function describes the spectral sensitivity of the eye better than V(λ), VM(λ) or V10(λ) functions at low photopic luminance levels (≤ 20 cd/m2). At mesopic luminance levels (≥ 0.1 cd/m2), it was investigated how a linear combination of photopic and scotopic spectral luminous efficiency functions describes the spectral sensitivity of the eye in peripheral vision. A model for the mesopic spectral luminous efficiency function Vmes(λ) was developed for peripheral vision. The results showed that this function describes the peripheral spectral sensitivity with best accuracy at mesopic luminance levels. The new function was compared with the proposed unified system of photometry by Rea, Bullough, Freyssinier-Nova and Bierman (2004). The function developed in this work described the measurement results with much higher accuracy. A sigmoid function was developed to describe the mesopic spectral luminous efficiency function as a combination of photopic and scotopic spectral luminous efficiency functions. This function can be used to calculate the weighting coefficient from 0.1 cd/m2 upwards.

Report / Helsinki University of Technology, Lighting Laboratory, ISSN 1795-9039; 37

Advisors/Committee Members: Helsinki University of Technology, Department of Electrical and Communications Engineering, Lighting Laboratory.

Subjects/Keywords: peripheral vision; mesopic vision; reaction time; contrast threshold; spectral luminous efficiency function

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Orreveteläinen, P. (2005). Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels. (Thesis). Helsinki University of Technology. Retrieved from http://lib.tkk.fi/Diss/2005/isbn951227857X/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Orreveteläinen, Pasi. “Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels.” 2005. Thesis, Helsinki University of Technology. Accessed July 15, 2019. http://lib.tkk.fi/Diss/2005/isbn951227857X/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Orreveteläinen, Pasi. “Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels.” 2005. Web. 15 Jul 2019.

Vancouver:

Orreveteläinen P. Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels. [Internet] [Thesis]. Helsinki University of Technology; 2005. [cited 2019 Jul 15]. Available from: http://lib.tkk.fi/Diss/2005/isbn951227857X/.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Orreveteläinen P. Models for Spectral Luminous Efficiency in Peripheral Vision at Mesopic and Low Photopic Luminance Levels. [Thesis]. Helsinki University of Technology; 2005. Available from: http://lib.tkk.fi/Diss/2005/isbn951227857X/

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


NSYSU

3. Tang, Sheng-Yi. Investigation on High Frequency Operating Characteristics of Metal Halide Lamp.

Degree: Master, Electrical Engineering, 2004, NSYSU

The operating characteristics of metal halide lamps are investigated, including acoustic resonance, spectral energy, and luminous efficacy. To operate metal halide lamps at intended conditions, two test sophisticated ballast circuits are built to drive the lamps with sine-wave current and square-wave current, respectively. One ballast employs the series resonant inverter to output sinusoidal lamp current over a high-frequency range from 20 kHz to 300 kHz. The other makes use of the full-bridge inverter to drive the lamps with square-wave current from 50 Hz up to 300 kHz. For both test circuits, the operating frequency and the magnitude of the lamp current can be controlled independently. On the other hand, the lamp power is adjusted by regulating the DC-link power. Several conclusions are drawn from experimental results: (1) Little difference is found between the lighting spectra of a lamp when driven by sinusoidal current and square-wave current. (2) Luminous efficiency deteriorates as the operating frequency increases. The deterioration is more significant at lower frequencies. (3) Luminous efficiency decreases considerably as the lamp power is reduced. (4) Arc instability from acoustic resonance is highly related to the waveform of the lamp current. The investigated results give better understanding on the steady state operation of metal halide lamps and provide useful information for the design of the electronic ballasts. Advisors/Committee Members: Tsong-Juu Liang (chair), Jiann-Fun Chen (chair), Ching-Ran Lee (chair), Li-Ling Lee (chair), Chin-Sien Moo (committee member).

Subjects/Keywords: luminous efficiency; Metal halide lamp; acoustic resonance; electronic ballast; spectral energy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tang, S. (2004). Investigation on High Frequency Operating Characteristics of Metal Halide Lamp. (Thesis). NSYSU. Retrieved from http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0703104-191800

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Tang, Sheng-Yi. “Investigation on High Frequency Operating Characteristics of Metal Halide Lamp.” 2004. Thesis, NSYSU. Accessed July 15, 2019. http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0703104-191800.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Tang, Sheng-Yi. “Investigation on High Frequency Operating Characteristics of Metal Halide Lamp.” 2004. Web. 15 Jul 2019.

Vancouver:

Tang S. Investigation on High Frequency Operating Characteristics of Metal Halide Lamp. [Internet] [Thesis]. NSYSU; 2004. [cited 2019 Jul 15]. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0703104-191800.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tang S. Investigation on High Frequency Operating Characteristics of Metal Halide Lamp. [Thesis]. NSYSU; 2004. Available from: http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0703104-191800

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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