Observations on Spatial-Frequency Doubling

Perception ◽  
1974 ◽  
Vol 3 (1) ◽  
pp. 81-86 ◽  
Author(s):  
C W Tyler
Keyword(s):  
Spatial Frequency ◽  
Transient Response ◽  
Frequency Doubling ◽  
Amacrine Cells ◽  
Distortion Model ◽  
Detection Model ◽  
Disparity Detection

The involvement of disparity detectors in the perception of spatial-frequency doubling in a flickering grating was tested by viewing the grating horizontally. Frequency doubling was unimpaired, and must therefore occur independently of disparity detection. A distortion model of frequency doubling was compared with a flicker-detection model, in predicting the appearance of nonsinusoidal gratings. The results support the flicker-detection model but not the distortion model. Physiological considerations suggest that spatial-frequency doubling may be mediated by the transient response of the amacrine cells in the retina.

Insights for mfVEPs from perimetry using large spatial frequency-doubling and near frequency-doubling stimuli in glaucoma

2020 ◽  
Vol 141 (1) ◽  
pp. 45-55
Author(s):  
Siti Nurliyana Abdullah ◽  
Gordon F. Sanderson ◽  
Mohd Aziz Husni ◽  
Ted Maddess
Keyword(s):  
Spatial Frequency ◽  
Frequency Doubling

Deposition of Cr Atoms Using Switching-Detuning Light Mask for Direct Atom Lithography

2019 ◽  
Vol 15 (6) ◽  
pp. 626-630
Author(s):  
Li Zhu ◽  
Xiao Deng ◽  
Jie Liu ◽  
Xinbin Cheng ◽  
Tongbao Li
Keyword(s):  
Spatial Frequency ◽  
Deposition Time ◽  
Frequency Doubling ◽  
Deposition Process ◽  
Atom Beam ◽  
High Uniformity ◽  
Dipole Force ◽  
Scaling Down ◽  
Pitch Distance ◽  
Atom Lithography

Background: As progress on the nanofabrication has made semiconductor developed rapidly, there is an increasing need in precise pitch standards to calibrate the structure of devices at nanoscale. Nano-gratings fabricated by atom lithography are unique and suitable to act as precise pitch standard because its pitch distance is directly traceable to a natural constant. As the scaling down of nano-devices, it is very challenging to double the spatial frequency of nano-grating while keeping the self-traceability in atom lithography. Methods: In this study, the switching-detuning light mask is utilized for Cr atom lithography. During a single deposition process, the standing wave frequency is switching from positive detuning to negative detuning alternatively. Results: Nano-gratings fabricated using switching-detuning light mask is successfully replicated with double spatial frequency and self-traceability. Non-uniformity between neighboring Cr lines shows up with a corrected pitch of 107.15 Conclusion: Non-uniformity is mainly caused by the dipole force discrepancy between positive and negative detuning light mask. Therefore, to increase the high uniformity of nano-gratings, the deposition time of negative detuning should be at least twice as the positive detuning. On the other hand, to reduce the pitch uncertainty, it is necessary to reduce the distance between the atom beam and reflection mirror as close as possible. These two significant optimization designs are promising to increase the spatial frequency doubling performance with high uniformity and accuracy.

Spatial frequency doubling with two-step technique

2014 ◽  
Vol 39 (7) ◽  
pp. 2024
Author(s):  
Sensen Li ◽  
Lujian Chen ◽  
Xiaopeng Dong ◽  
Xuechang Ren ◽  
Xiangsu Zhang ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Frequency Doubling

Spatial Frequency Doubling Method by Image Superimposition for Sub-$\bf 0.15\mbox{-}{\mbi \mu }m$ Optical Lithography

1995 ◽  
Vol 34 (Part 1, No. 12A) ◽  
pp. 6518-6525
Author(s):  
Akihiro Otaka ◽  
Yoshio Kawai ◽  
Akinobu Tanaka ◽  
Tadahito Matsuda
Keyword(s):  
Spatial Frequency ◽  
Frequency Doubling ◽  
Optical Lithography ◽  
Doubling Method

A new interpretation of components in the ERG signals to sine wave luminance stimuli at different temporal frequencies and contrasts

2010 ◽  
Vol 27 (3-4) ◽  
pp. 79-90 ◽  
Author(s):  
GOBINDA PANGENI ◽  
FOLKERT K. HORN ◽  
JAN KREMERS
Keyword(s):  
Transient Response ◽  
Second Harmonic ◽  
Human Subjects ◽  
Harmonic Component ◽  
Low Frequency ◽  
Frequency Doubling ◽  
Sine Wave ◽  
Frequency Region ◽  
High Frequency Region ◽  
Full Field

AbstractFull-field electroretinograms were recorded from five normal human subjects using white light (mean luminance: 250 cd/m2) sine wave stimuli at different frequencies and contrasts. In agreement with previous studies, we found that the amplitude of the fundamental component displayed a dip at about 12 Hz, coinciding with a maximum in the second harmonic component, indicating frequency doubling of the responses. By including measurements at different contrasts, we were able to recognize two (sine-like and transient) response components. We found that the waveform of the transient response was relatively frequency independent. An algorithm to separate the two components was developed. The interaction between these two components can explain the frequency-doubled responses around 12 Hz. The sine-like component is more linear and prominent in the low-frequency region, whereas the transient seems to be more nonlinear and prominent in the high-frequency region.

scholarly journals Adaptation to a ‘Spatial-Frequency Doubled’ Stimulus

Perception ◽  
1980 ◽  
Vol 9 (5) ◽  
pp. 523-528 ◽  
Author(s):  
Peter Thompson ◽  
Brian J Murphy
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Frequency Tuning ◽  
Low Frequency ◽  
Frequency Doubling ◽  
Contrast Threshold ◽  
Threshold Elevation ◽  
Temporal Parameters ◽  
Spatial Frequency Tuning ◽  
Sinusoidal Gratings

The perceived spatial frequency of low-frequency sinusoidal gratings is elevated when the gratings are temporally modulated sufficiently rapidly. Although this phenomenon is usually called ‘spatial-frequency doubling’, the magnitude of this spatial-frequency elevation depends on the spatial and temporal parameters of the grating and may be less than or greater than doubling. Adaptation to such a pattern produces contrast-threshold elevation whose spatial-frequency tuning is centred upon the grating's real rather than perceived spatial frequency. These results suggest that spatial-frequency elevation occurs later in the visual system than adaptation or that these two processes are independent of one another, at least under the conditions of these experiments.

Compound Bragg reflection filters made by spatial frequency doubling lithography

1989 ◽  
Vol 7 (9) ◽  
pp. 1379-1385 ◽  
Author(s):  
C.H. Henry ◽  
Y. Shani ◽  
R.C. Kistler ◽  
T.E. Jewell ◽  
V. Pol ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Bragg Reflection ◽  
Frequency Doubling
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