A visual attention system, inspired by the behavior and the neuronal architecture of the early primate visual system, is presented. Multiscale image features are combined into a single topographical saliency map. A dynamical neural network then selects attended locations in order of decreasing saliency. The system breaks down the complex problem of scene understanding by rapidly selecting, in a computationally efficient manner, conspicuous locations to be analyzed in detail.

/pdf/a-model-of-saliency-based-visual-attention-for-rapid-scene-wv0n3yqxix.pdf

A model of saliency-based visual attention for rapid scene analysis

http://ilab.usc.edu/publications/doc/Itti_Koch00vr.pdf

A saliency-based search mechanism for overt and covert shifts of visual attention.

A computer-implemented method for use in conjunction with a computing device with a touch screen display comprises: detecting one or more finger contacts with the touch screen display, applying one or more heuristics to the one or more finger contacts to determine a command for the device, and processing the command. The one or more heuristics comprise: a heuristic for determining that the one or more finger contacts correspond to a one- dimensional vertical screen scrolling command, a heuristic for determining that the one or more finger contacts correspond to a two-dimensional screen translation command, and a heuristic for determining that the one or more finger contacts correspond to a command to transition from displaying a respective item in a set of items to displaying a next item in the set of items.

Touch screen device, method, and graphical user interface for determining commands by applying heuristics

http://math.bu.edu/people/horacio/tutorials/jascha_2.pdf

The lateral occipital complex and its role in object recognition.

The primate retina contains three classes of cones, the L, M and S cones, which respond preferentially to long-, middle- and short-wavelength visible light, respectively. Colour appearance results from neural processing of these cone signals within the retina and the brain. Perceptual experiments have identified three types of neural pathways that represent colour: a red–green pathway that signals differences between L- and M-cone responses; a blue–yellow pathway that signals differences between S-cone responses and a sum of L- and M-cone responses; and a luminance pathway that signals a sum of L- and M-cone responses1,2,3. It might be expected that there are neurons in the primary visual cortex with response properties that resemble these three perceptual pathways, but attempts to find them have led to inconsistent results4,5,6,7. We have therefore used functional magnetic resonance imaging (fMRI) to examine responses in the human brain to a large number of colours. In visual cortical areas V1 and V2, the strongest response is to red–green stimuli, and much of this activity is from neurons receiving opposing inputs from L and M cones. A strong response is also seen with blue–yellow stimuli, and this response declines rapidly as the temporal frequency of the stimulus is increased. These responses resemble psychophysical measurements, suggesting that colour signals relevant for perception are encoded in a large population of neurons in areas V1 and V2.

/pdf/colour-tuning-in-human-visual-cortex-measured-with-y74qd2ax96.pdf

Colour tuning in human visual cortex measured with functional magnetic resonance imaging.

Color image fidelity metrics evaluated using image distortion maps

We describe experimental tests of a spatial extension to the CIELAB color metric for measuring color reproduction errors of digital images. The standard CIELAB /spl Delta/E metric is suitable for use on large uniform color targets, but not on images, because color sensitivity changes as a function of spatial pattern. The S-CIELAB extension includes a spatial processing step, prior to the CIELAB /spl Delta/E calculation, so that the results correspond better to color difference perception by the human eye. The S-CIELAB metric was used to predict texture visibility of printed halftone patterns. The results correlate with perceptual data better than standard CIELAB and point the way to various improvements.

Color image quality metric S-CIELAB and its application on halftone texture visibility

Electronic devices having image-based data input systems are described. In one aspect, an electronic device includes a window, multiple indicia, an image sensor, and a data input processor. The window has a contact surface with an input region. The multiple indicia are viewable in the input region of the contact surface. The image sensor is constructed and arranged to produce image signals corresponding to images of the input region. The data input processor is coupled to the image sensor and is operable to produce input signals based on image signals produced by the image sensor and a mapping between areas of the input region images and locations of the input indicia.

Electronic device having an image-based data input system

An adaptive image tone mapping curve based on perceptual preference guidelines is generated as a sigmoidal function, in which the sigmoidal function parameters (slope and shift) are determined by original image statistics. Tone curves generated for different images each have a smooth sigmoidal shape, so that the tone mapping process does not change the image histogram shape drastically. The sigmoidal function has the form: t ⁢ ( x ) = 100 1 + exp ⁢ ( - α ⁢ ( x / 100 - β ) ) , 
where α is the slope parameter and β is the shift parameter. The input value x in the sigmoidal function varies in the range [0, 100], because the tone curve is generated on an L* scale, which has values from 0 to 100. The sigmoidal tone curve calculation can be implemented efficiently using simple arithmetic operations by pre-calculating and storing various factors used in the calculation of α and β and by pre-generating a pair of fixed tone curves with two extreme slopes and interpolating between the curves.

Xuemei Zhang

Papers

Colour tuning in human visual cortex measured with functional magnetic resonance imaging.

Color image fidelity metrics evaluated using image distortion maps

Color image quality metric S-CIELAB and its application on halftone texture visibility

Electronic device having an image-based data input system

System and method for digital image tone mapping using an adaptive sigmoidal function based on perceptual preference guidelines