Adaptive Light Spot Removal Algorithm for Endoscopic Scenes

2021 ◽  
Author(s):  
Zhenyu Liang ◽  
Guodong Wei ◽  
Zhengang Jiang ◽  
Guanyuan Feng ◽  
Tao Chen ◽  
...  
Keyword(s):  
Light Spot

Turbulent broadening of the focal light spot formed by an annular aperture

1973 ◽  
Vol 16 (11) ◽  
pp. 1610-1612
Author(s):  
A. I. Kon ◽  
V. L. Mironov ◽  
V. E. Tseitlin
Keyword(s):  
Light Spot ◽  
Annular Aperture

scholarly journals Research and Design No Light Spot in Front Located Hysteroscopy

2017 ◽  
Vol 8 ◽  
pp. 01035
Author(s):  
Kun Dai ◽  
Bo Xiang ◽  
Zhaomin Jia
Keyword(s):  
Light Spot ◽  
Research And Design

The Cockroach DCMD Neurone: I. Lateral Inhibition and the Effects of Light- and Dark-adaptation

1982 ◽  
Vol 99 (1) ◽  
pp. 61-90 ◽  
Author(s):  
DONALD H. EDWARDS
Keyword(s):  
Lateral Inhibition ◽  
Dark Adaptation ◽  
Light Adaptation ◽  
Absolute Intensity ◽  
Recurrent Network ◽  
Light Spot ◽  
Movement Detector ◽  
Threshold Response ◽  
Inhibitory Network ◽  
Local Background

1. The responses of the cockroach descending contralateral movement detector (DCMD) neurone to moving light stimuli were studied under both light- and dark-adapted conditions. 2. With light-adaptation the response of the DCMD to two moving 2° (diam.) spots of white light is less than the response to a single spot when the two spots are separated by less than 10° (Fig. 2). 3. With light-adaptation the response of the DCMD to a single moving light spot is a sigmoidally shaped function of the logarithm of the light intensity (Fig. 3a). With dark-adaptation the response of a DCMD to a single moving light spot is a bell-shaped function of the logarithm of the stimulus intensity (Fig. 3b). The absolute intensity that evokes a threshold response is about one-and-a-half log units less in the dark-adapted eye than in the light-adapted eye. 4. The decrease in the DCMD's response that occurs when two stimuli are closer than 10°, and when a single bright stimulus is made brighter, indicates that lateral inhibition operates among the afferents to the DCMD. 5. It is shown that this inhibition cannot be produced by a recurrent lateral inhibitory network. A model of the afferent path that contains a non-recurrent lateral inhibitory network can account for the response/intensity plots of the DCMD recorded under both light-adapted and dark-adapted conditions. 6. The threshold intensity of the DCMD is increased if a stationary pattern of light is present near the path of the moving spot stimulus. This is shown to be due to a peripheral tonic lateral inhibition that is distinct from the non-recurrent lateral inhibition described earlier. 7. It is suggested that the peripheral lateral inhibition acts to adjust the threshold of afferents to local background light levels, while the proximal non-recurrent network acts to enhance the acuity of the eye to small objects in the visual field, and to filter out whole-field stimuli.

scholarly journals Ionic mechanisms of two types of on-center bipolar cells in the carp retina. I. The responses to central illumination.

1979 ◽  
Vol 73 (1) ◽  
pp. 73-90 ◽  
Author(s):  
T Saito ◽  
H Kondo ◽  
J I Toyoda
Keyword(s):  
Reversal Potential ◽  
Maximum Amplitude ◽  
Bipolar Cells ◽  
Light Spot ◽  
Membrane Properties ◽  
Resistance Increase ◽  
Membrane Conductances ◽  
Electric Interaction ◽  
Ionic Mechanisms ◽  
Resistance Decrease

Properties of the depolarizing response of on-center bipolar cells to a light spot stimulus were studied in the carp retina. On-center bipolar cells were classified into two types, cone-dominant and rod-dominant, according to their major input from cones and rods. Cone-dominant bipolar cells responded to spectral light with the maximum amplitude near 625 nm, suggesting major input from red cones. The response was accompanied by a resistance increase and showed a reversal potential at -63 +/- 21 mV when the membrane was hyperpolarized by current. The results suggest that the photoresponse of cone-dominant cells is due to a decrease of gK and/or gCl, membrane conductances to potassium and chloride, respectively. Rod-dominant bipolar cells responded to spectral light with the maximum amplitude near 525 nm under scotopic conditions and near 625 nm under photopic conditions, providing evidence that they receive input from rods and red cones. In the scoptopic condition their response was accompanied by a resistance decrease and showed a reversal potential at 29 +/- 13 mV, whereas in the photopic condition the response in most of them was accompanied by a resistance increase, at least in their part and showed a reversal at -53 +/- 11 mV. The results suggest that the photoresponse activated by rod input is due to an increase in gNa. In the mesopic condition rod-dominant cells showed complex electrical membrane properties as the result of electric interaction between the above two differnt ionic mechanisms activated by rod and cone inputs.

scholarly journals Sub-Frame Evaluation of Frame Synchronization for Camera Network Using Linearly Oscillating Light Spot

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6148
Author(s):  
Hyuno Kim ◽  
Masatoshi Ishikawa
Keyword(s):  
Visual Information ◽  
Evaluation Method ◽  
Measurement Instrument ◽  
Light Spot ◽  
Estimation Accuracy ◽  
Accurate Data ◽  
Frame Synchronization ◽  
Camera Network ◽  
Novel Method ◽  
Synchronization Accuracy

Precisely evaluating the frame synchronization of the camera network is often required for accurate data fusion from multiple visual information. This paper presents a novel method to estimate the synchronization accuracy by using inherent visual information of linearly oscillating light spot captured in the camera images instead of using luminescence information or depending on external measurement instrument. The suggested method is compared to the conventional evaluation method to prove the feasibility. Our experiment result implies that the estimation accuracy of the frame synchronization can be achieved in sub-millisecond order.

Photovoltaic Characterization of Trapping in Porous Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
D. W. Boeringer ◽  
R. Tsu
Keyword(s):  
Porous Silicon ◽  
Photovoltaic Effect ◽  
Light Spot ◽  
Dangling Bond ◽  
Photogenerated Electrons ◽  
Device Applications ◽  
Photovoltaic Characterization ◽  
P Type ◽  
Silicon Based ◽  
Position Sensitive Detectors

ABSTRACTWe report the first observation of the lateral photovoltaic effect in porous silicon. Contacts placed on either side of a porous silicon region develop a voltage up to several millivolts if the sample is asymmetrically illuminated. If the light spot is closer to one contact, the voltage will have one polarity; if it is closer to the other contact, the polarity will be opposite. In the case of n-type, the contact nearest the light spot is positive; for p-type, the contact nearest the light spot is negative In the region between the contacts, the photovoltage varies almost linearly with the position of the light spot, over a distance 4.5 cm across. The origin of our lateral photoeffect may be explained by the trapping of photoexcited carriers by a pair of dangling bond centers in porous silicon. In the case of p-type, the photogenerated electrons are trapped by the dangling bond states while holes diffuse away in the substrate. The situation for n-type is opposite; holes are trapped by the dangling bond states while electrons diffuse away in the substrate. This differs from the conventional lateral photoeffect, which arises under the nonuniform illumination of a junction between two layers of differing conductivities. Hamamatsu sells silicon-based position-sensitive detectors with a resolution down to 0.1 µm. The possibility of using this lateral photoeffect to characterize these dangling bond states in porous silicon as well as several possible device applications will be discussed.

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