natural scene statistics
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2022 ◽  
Author(s):  
Divyansh Gupta ◽  
Wiktor Mlynarski ◽  
Olga Symonova ◽  
Jan Svaton ◽  
Maximilian Joesch

Visual systems have adapted to the structure of natural stimuli. In the retina, center-surround receptive fields (RFs) of retinal ganglion cells (RGCs) appear to efficiently encode natural sensory signals. Conventionally, it has been assumed that natural scenes are isotropic and homogeneous; thus, the RF properties are expected to be uniform across the visual field. However, natural scene statistics such as luminance and contrast are not uniform and vary significantly across elevation. Here, by combining theory and novel experimental approaches, we demonstrate that this inhomogeneity is exploited by RGC RFs across the entire retina to increase the coding efficiency. We formulated three predictions derived from the efficient coding theory: (i) optimal RFs should strengthen their surround from the dimmer ground to the brighter sky, (ii) RFs should simultaneously decrease their center size and (iii) RFs centered at the horizon should have a marked surround asymmetry due to a stark contrast drop-off. To test these predictions, we developed a new method to image high-resolution RFs of thousands of RGCs in individual retinas. We found that the RF properties match theoretical predictions, and consistently change their shape from dorsal to the ventral retina, with a distinct shift in the RF surround at the horizon. These effects are observed across RGC subtypes, which were thought to represent visual space homogeneously, indicating that functional retinal streams share common adaptations to visual scenes. Our work shows that RFs of mouse RGCs exploit the non-uniform, panoramic structure of natural scenes at a previously unappreciated scale, to increase coding efficiency.


2021 ◽  
Author(s):  
Paul Linton

Human 3D vision is thought to triangulate the size, distance, direction, and 3D shape of objects using vision from the two eyes. But all four of these capacities rely on the visual system knowing where the eyes are pointing. Dr Linton's experimental work on size and distance challenge this account, suggesting a purely retinal account of visual size and distance, and likely direction and 3D shape. This requires new accounts of visual scale and visual shape. For visual scale, he argues that observers rely on natural scene statistics to associate accentuated stereo depth (largely from horizontal disparities) with closer distances. This implies that depth / shape is resolved before size and distance. For visual shape, he argues that depth / shape from the two eyes is a solution to a different problem (rivalry eradication between two retinal images treated as if they are from the same viewpoint), rather than the visual system attempting to infer scene geometry (by treating the two retinal images as two different views of the same scene from different viewpoints). Dr Linton also draws upon his book, which questions whether other depth cues (perspective, shading, motion) really have any influence on this process.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Richard F. Murray

Lightness perception is the perception of achromatic surface colors: black, white, and shades of grey. Lightness has long been a central research topic in experimental psychology, as perceiving surface color is an important visual task but also a difficult one due to the deep ambiguity of retinal images. In this article, I review psychophysical work on lightness perception in complex scenes over the past 20 years, with an emphasis on work that supports the development of computational models. I discuss Bayesian models, equivalent illumination models, multidimensional scaling, anchoring theory, spatial filtering models, natural scene statistics, and related work in computer vision. I review open topics in lightness perception that seem ready for progress, including the relationship between lightness and brightness, and developing more sophisticated computational models of lightness in complex scenes. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


2021 ◽  
pp. 1-10
Author(s):  
Georgina Powell ◽  
Olivier Penacchio ◽  
Hannah Derry-Sumner ◽  
Simon K. Rushton ◽  
Deepak Rajenderkumar ◽  
...  

BACKGROUND: Images that deviate from natural scene statistics in terms of spatial frequency and orientation content can produce visual stress (also known as visual discomfort), especially for migraine sufferers. These images appear to over-activate the visual cortex. OBJECTIVE: To connect the literature on visual discomfort with a common chronic condition presenting in neuro-otology clinics known as persistent postural perceptual dizziness (PPPD). Sufferers experience dizziness when walking through highly cluttered environments or when watching moving stimuli. This is thought to arise from maladaptive interaction between vestibular and visual signals for balance. METHODS: We measured visual discomfort to stationary images in patients with PPPD (N = 30) and symptoms of PPPD in a large general population cohort (N = 1858) using the Visual Vertigo Analogue Scale (VVAS) and the Situational Characteristics Questionnaire (SCQ). RESULTS: We found that patients with PPPD, and individuals in the general population with more PPPD symptoms, report heightened visual discomfort to stationary images that deviate from natural spectra (patient comparison, F (1, 1865) = 29, p <  0.001; general population correlations, VVAS, rs (1387) = 0.46, p <  0.001; SCQ, rs (1387) = 0.39, p <  0.001). These findings were not explained by co-morbid migraine. Indeed, PPPD symptoms showed a significantly stronger relationship with visual discomfort than did migraine (VVAS, zH = 8.81, p <  0.001; SCQ, zH  = 6.29, p <  0.001). CONCLUSIONS: We speculate that atypical visual processing –perhaps due to a visual cortex more prone to over-activation –may predispose individuals to PPPD, possibly helping to explain why some patients with vestibular conditions develop PPPD and some do not.


2020 ◽  
Author(s):  
Yongrong Qiu ◽  
Zhijian Zhao ◽  
David Klindt ◽  
Magdalena Kautzky ◽  
Klaudia P. Szatko ◽  
...  

SummaryPressures for survival drive sensory circuit adaption to a species’ habitat, making it essential to statistically characterise natural scenes. Mice, a prominent visual system model, are dichromatic with enhanced sensitivity to green and UV. Their visual environment, however, is rarely considered. Here, we built a UV-green camera to record footage from mouse habitats. We found chromatic contrast to greatly diverge in the upper but not the lower visual field, an environmental difference that may underlie the species’ superior colour discrimination in the upper visual field. Moreover, training an autoencoder on upper but not lower visual field scenes was sufficient for the emergence of colour-opponent filters. Furthermore, the upper visual field was biased towards dark UV contrasts, paralleled by more light-offset-sensitive cells in the ventral retina. Finally, footage recorded at twilight suggests that UV promotes aerial predator detection. Our findings support that natural scene statistics shaped early visual processing in evolution.Lead contactFurther information and requests for resources and reagents should be directed to and will be fulfilled by the Lead Contact, Thomas Euler ([email protected])


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