scholarly journals Spectral Response Curves and Receptive Fields of Pre- and Postgeniculate Fibres of the Cat

1960 ◽  
Vol 71 (4) ◽  
pp. 401-415 ◽  
Author(s):  
Hisao Suzuki ◽  
Norio Taira ◽  
Koiti Motokawa
Keyword(s):  
Spectral Response ◽  
Receptive Fields ◽  
Response Curves

scholarly journals Characterizing Changes in Soybean Spectral Response Curves with Breeding Advancements

Crop Science ◽  
2014 ◽  
Vol 54 (4) ◽  
pp. 1585-1597 ◽  
Author(s):  
Brent S. Christenson ◽  
William T. Schapaugh ◽  
Nan An ◽  
Kevin P. Price ◽  
Allan K. Fritz
Keyword(s):  
Spectral Response ◽  
Response Curves

Method to validate relative spectral response curves

1998 ◽  
Author(s):  
John E. Hubbs ◽  
John P. Garcia ◽  
Eustace L. Dereniak
Keyword(s):  
Spectral Response ◽  
Response Curves

Electrophysiological response of Dendroctonus pseudotsugae and Ips paraconfusus (Coleoptera: Scolytidae) to selected wavelength regions of the visible spectrum

1982 ◽  
Vol 60 (9) ◽  
pp. 2180-2189 ◽  
Author(s):  
L. J. Groberman ◽  
J. H. Borden
Keyword(s):  
Fiber Optics ◽  
Spatial Information ◽  
Spectral Response ◽  
Visible Spectrum ◽  
Ips Paraconfusus ◽  
Compound Eyes ◽  
Response Curves ◽  
Dendroctonus Pseudotsugae ◽  
Electrophysiological Response ◽  
Sensitivity Curves

Electroretinograms (ERGs) were recorded from the compound eyes of both sexes of Dendroctonus pseudotsugae Hopkins and Ips paraconfusus (Lanier). Light stimuli between 400 and 650 nm were delivered to the compound eyes through a monochromator connected to a fiber-optics and lens light-delivery system. Stimulus intensity was regulated with neutral density filters. The averaged spectral response curves were similar for both species and sexes. The spectral sensitivity curves disclosed two sensitivity maxima, one in the blue region (450 nm) and one in the green region (510 to 530 nm). These correspond well with behavioural data on scolytids and with response peaks reported in other insects and provide evidence that the scolytid visual system consists of two receptor types. The blue receptors are probably used in navigation during the initial stages of the dispersal flight and the green receptors for the detection of spatial information during host selection.

scholarly journals NATIONAL GUIDELINES FOR DIGITAL CAMERA SYSTEMS CERTIFICATION

2016 ◽  
Vol XLI-B1 ◽  
pp. 179-184
Author(s):  
Yaron Yaron ◽  
Eran Keinan ◽  
Moshe Benhamu ◽  
Ronen Regev ◽  
Garry Zalmanzon
Keyword(s):  
Laser Scanning ◽  
Spectral Response ◽  
Spectral Characteristics ◽  
Digital Camera ◽  
Director General ◽  
National Guidelines ◽  
Response Curves ◽  
High Quality ◽  
Camera Systems ◽  
Imaging Sensors

Digital camera systems are a key component in the production of reliable, geometrically accurate, high-resolution geospatial products. These systems have replaced film imaging in photogrammetric data capturing. Today, we see a proliferation of imaging sensors collecting photographs in different ground resolutions, spectral bands, swath sizes, radiometric characteristics, accuracies and carried on different mobile platforms. In addition, these imaging sensors are combined with navigational tools (such as GPS and IMU), active sensors such as laser scanning and powerful processing tools to obtain high quality geospatial products. The quality (accuracy, completeness, consistency, etc.) of these geospatial products is based on the use of calibrated, high-quality digital camera systems. <br><br> The new survey regulations of the state of Israel specify the quality requirements for each geospatial product including: maps at different scales and for different purposes, elevation models, orthophotographs, three-dimensional models at different levels of details (LOD) and more. In addition, the regulations require that digital camera systems used for mapping purposes should be certified using a rigorous mapping systems certification and validation process which is specified in the Director General Instructions. The Director General Instructions for digital camera systems certification specify a two-step process as follows: <br><br> 1. Theoretical analysis of system components that includes: study of the accuracy of each component and an integrative error propagation evaluation, examination of the radiometric and spectral response curves for the imaging sensors, the calibration requirements, and the working procedures. <br><br> 2. Empirical study of the digital mapping system that examines a typical project (product scale, flight height, number and configuration of ground control points and process). The study examine all the aspects of the final product including; its accuracy, the product pixels size on the ground (spatial resolution), its completeness (missing pixels and striping affect), its radiometric properties (e.g., relative edge response) and its spectral characteristics (e.g., histogram spread, bands misalignment). <br><br> This methodology was tested on a number of medium to large format digital cameras. The certification process is a basic stage in the mapping chain in Israel. This article provides the details of the Director General Instructions for digital camera systems certification, the methodology for certification and the tests that were carried out.

Neuronal and behavioural responses in rats during noxious stimulation of the tail

1977 ◽  
Vol 197 (1127) ◽  
pp. 169-194 ◽  
Keyword(s):  
Dorsal Horn ◽  
Receptive Fields ◽  
Temperature Response ◽  
Threshold Temperature ◽  
Noxious Stimulation ◽  
Mechanical Stimuli ◽  
Response Curves ◽  
Ventrobasal Nucleus ◽  
Behavioural Experiments ◽  
Stimulation Of

In rats anaesthetized with urethane, extracellular unit activity has been recorded from neurones in the central nervous system during noxious stimulation of the tail. Accurately graded and sustained stimulation was achieved by immersing the whole tail in water at controlled temperatures. Neurones were found chiefly in the marginal layers of the dorsal horn near the entry of the dorsal roots supplying the tail and in the ventrobasal nucleus of the thalamus; a few neurones were also found in the somatosensory cortex. Both dorsal horn units and thalamic units showed very similar responses as the tail temperature was gradually raised. At 42°C there was an increase in firing rate which rose sharply with increasing temperatures to reach a maximum at 46°C. At higher temperatures activ­ity declined and at temperatures above 50°C was largely extinguished. The temperature-response curves were bell-shaped. The decline in activity depended on temperature and not on time: sustained firing for many minutes was seen when temperature was at or just below the peak of the bell-shaped curve. The dorsal horn and thalamic cells also responded to noxious mechanical stimulation of the tail. The receptive fields at both levels were similar, being variable in size, often bilateral and sometimes covering the whole tail. None of the central neurones showed any response to noxious stimulation other than on the tail; neither did they respond to movement of the tail nor to light mechanical stimuli applied to the tail or elsewhere. In behavioural experiments conscious rats had their tails exposed to water at various temperatures. The rats lifted their tails from the water at a threshold temperature of 43.7 ± 0.6°C, i. e. just above the threshold for the central nociceptive neurones. The findings are compatible with a specific nociceptive pathway ascending to the ventrobasal thalamus.

An evaluation of the two-dimensional Gabor filter model of simple receptive fields in cat striate cortex

1987 ◽  
Vol 58 (6) ◽  
pp. 1233-1258 ◽  
Author(s):  
J. P. Jones ◽  
L. A. Palmer
Keyword(s):  
Gabor Filter ◽  
Spectral Response ◽  
Receptive Fields ◽  
Gabor Filters ◽  
Simple Cell ◽  
Two Dimensional ◽  
Gabor Function ◽  
Spatial Response ◽  
Response Profile ◽  
Response Profiles

1. Using the two-dimensional (2D) spatial and spectral response profiles described in the previous two reports, we test Daugman's generalization of Marcelja's hypothesis that simple receptive fields belong to a class of linear spatial filters analogous to those described by Gabor and referred to here as 2D Gabor filters. 2. In the space domain, we found 2D Gabor filters that fit the 2D spatial response profile of each simple cell in the least-squared error sense (with a simplex algorithm), and we show that the residual error is devoid of spatial structure and statistically indistinguishable from random error. 3. Although a rigorous statistical approach was not possible with our spectral data, we also found a Gabor function that fit the 2D spectral response profile of each simple cell and observed that the residual errors are everywhere small and unstructured. 4. As an assay of spatial linearity in two dimensions, on which the applicability of Gabor theory is dependent, we compare the filter parameters estimated from the independent 2D spatial and spectral measurements described above. Estimates of most parameters from the two domains are highly correlated, indicating that assumptions about spatial linearity are valid. 5. Finally, we show that the functional form of the 2D Gabor filter provides a concise mathematical expression, which incorporates the important spatial characteristics of simple receptive fields demonstrated in the previous two reports. Prominent here are 1) Cartesian separable spatial response profiles, 2) spatial receptive fields with staggered subregion placement, 3) Cartesian separable spectral response profiles, 4) spectral response profiles with axes of symmetry not including the origin, and 5) the uniform distribution of spatial phase angles. 6. We conclude that the Gabor function provides a useful and reasonably accurate description of most spatial aspects of simple receptive fields. Thus it seems that an optimal strategy has evolved for sampling images simultaneously in the 2D spatial and spatial frequency domains.

Improved Concept for Nipiin and PIIIN Color Sensitive Two-Terminal Devices with High Linearity

1997 ◽  
Vol 467 ◽  
Author(s):  
D. Knipp ◽  
H. Stiebig ◽  
J. Fölsch ◽  
R. Carius ◽  
H. Wagner
Keyword(s):  
Light Intensity ◽  
Dynamic Range ◽  
Layer Structure ◽  
Spectral Response ◽  
Incident Light ◽  
High Dynamic Range ◽  
Optical Signal ◽  
Optimized Design ◽  
Defect States ◽  
Response Curves

ABSTRACTThe detection of the fundamental components of the visible light (blue, green, red) is achieved with two terminal photo diodes based on amorphous silicon. By changing the bias voltage the preferential carrier collection region is shifted which leads to a color sensitivity. In order to obtain a high dynamic range, independent voltage controlled spectral response curves as well as a linear response of the photocurrent on the incident light intensity the μτ-product and the bandgap in the device have to be specially designed to deconvolute the optical signal and generate an RGB-signal. Since the light intensity can strongly influence the spectral sensitivity by recharging of defect states, an optimized design of the multi-layer structure is necessary. Therefore, an improved concept for the design of nipiin- and piiin-detectors is presented which results in a good suppression of these non-linearities. Our concept is based on a decreasing bandgap profile from the front to the back contact and an increasing μτ-product of the individual i-layers in direction of the p-layer.

scholarly journals A Sensor Designed to Record Underwater Irradiance with Concern for a Shark’s Spectral Sensitivity

Biosensors ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 105
Author(s):  
A. Peter Klimley
Keyword(s):  
Spectral Response ◽  
High Light ◽  
Sensory Receptors ◽  
Response Curves ◽  
Low Light ◽  
Scalloped Hammerhead ◽  
Light Levels ◽  
Irradiation Energy ◽  
Underwater Irradiance ◽  
Peak Sensitivity

To ascertain how scalloped hammerhead sharks make nightly migrations to their feeding grounds as many as 20 km from their daytime abode, a seamount, a sensor was developed that measured irradiance intensity within the spectral range and sensitivity of the vision of the species. Could the sharks guide their movements by sensing the polarity of irradiation energy radiated from the sun or moon that penetrated into the oceanic depths? Two sensory receptors, cones and rods, are present in the retina of sharks to enable them to see both during daytime and nighttime. The peak sensitivity of the cones is red-shifted due to the presence of these wavelengths during the former period, while their response is linear under the range of the high light levels also present at this time; the peak sensitivity of rods is blue-shifted due to the presence of these wavelengths during dawn, dusk, and nighttime and is linear over the complementary range of low light levels. Spectral response curves for these two receptors were determined for sharks, and an attempt was made to match those of the sensors to the shark’s wavelength perception. The first sensor was matched to the photopic range using a photocell covered with a red-shifted gel filter; the second was matched to the scotopic range using a blue-shifted gel filter.

Diurnal Changes in Structure and Function of the Compound Eye of Ligia Exotica (Crustacea, Isopoda)

1986 ◽  
Vol 123 (1) ◽  
pp. 1-26
Author(s):  
TAKAHIKO HARIYAMA ◽  
V. BENNO MEYER-ROCHOW ◽  
EISUKE EGUCHI
Keyword(s):  
Compound Eye ◽  
Spectral Response ◽  
Green Light ◽  
Diurnal Changes ◽  
Response Curves ◽  
Continuous Darkness ◽  
Closed Type ◽  
And Function ◽  
Two Peaks ◽  
Irregular Arrangement

The ultrastructure of the retinula cells of Ligia exotica changes diurnally and in response to light/dark adaptation. At the low phase of electroretinogram (ERG) amplitude (at noon), the arrangement of microvilli is ordered and the rhabdom is of the open type. An irregular arrangement of microvilli appears at the high phase of ERG amplitude (at midnight), when the rhabdom is of the closed type. The pigment granules disperse at midnight and assemble at noon. A centrally positioned, spikeproducing eccentric cell is present in each ommatidium. Spectral response curves based on ERG measurements have two maxima, one to light of 383 nm wavelength, the other at around 520 nm. These two peaks represent the two classes of receptor cells identified by intracellular recordings. The ERG responses to light of 383 nm and 520 nm wavelengths display a diurnal rhythmicity, being high at night and low during the day. However, the responses to green light are more strongly affected than those to ultraviolet light. Consequently, the eye displays a relatively higher ultraviolet-sensitivity during the day, whereas at night sensitivity to green light is increased. This behaviour, which persists in continuous darkness, suggests that an endogenous mechanism is involved in bringing about the observed diurnal morphological and physiological changes in the compound eye of Ligia exotica.

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