Introduction to Color Vision

Color Vision Advantages

Color provided a unique source of information for picking out an object from its background (detection)

Color Important Contributions

To promote the detection of objects that stand out from their backgrounds; color vision, promotes figure/ground segmentation (sometimes color is the only resource of information)

For ability to detect the presence of objects….

Color helps us recognize (identification) & distinguish (discrimination) faster recognize objects helps remember them

Conway & Carroll Color Influences

• Basic Level: Color created a “pop-out” effect in search tasks

• Intermediate level: Color aids in grouping and cargorization

• Higher Level: Color contributed to memory, aesthetics, & communication

Color perception

Main purpose is to help us (and other species with color vision) detect discriminate, identify and remember objects

Color isn’t real

Color has no referent outside the quality bone of the other senses conveys qualities that are remotely analogous the quality of color aside from

How are colors seen in different languages?

In almost all cultures studied, everyday language manages to get by with about a dozen color terms.

Idiosyncratic

When people in our own culture are asked to assign names to various color samples, there is a good agreement on the names for just a handful of basic colors; beyond those basic few, color names assigned to color sample

Newton Main Insight of Color

Objects themselves are not colored; they only appear colored because they reflect light from particular regions of the visible spectrum, and this reflected light has the power to stir up a particular sensation

Semir Zeki’s Extendkon of Newton

“Nervous system, rather than analyze colors, takes what info there is in the external environment, namely the reflectance of different surfaces for different wavelengths of light & transforms that info to construct colors, using own algorithms to do so.

How visible spectrum work on objects with color?

Light reflected from that object must be picked up by an eye outfitted with the right kind of photoreceptors, signals from photoreceptors must be combined in ways by the visual neurons in the retina & brain

Definition of Color

A products of the brain not the world. Because some people have abnormal eyes or brains, their experiences of color can & do different things radically from those most people enjoy

Refined Statement of Newtons Idea of British psychologist Semir Zeki

Color arises from the capacity of particular light rays to evoke certain responses in the nervous system

Hue

The quality that distinguishes red from yellow or green, or blue from orange etc.

Brightness

To the perceived quantity to light emitted by a stimulus

Ex. Brightness

A star, may be “bright” or “dim,” with surfaces use term lightness, 1 apple may look lighter than another red apple b/c surface former reflects more light than surface of latter

Saturation

Characterized a color as “pale,” “vivid,” or something in between

Ex. Saturation

After jeans have been washed a lot of times, their blueness will be less saturated than when you first got them.