The range of values spanned by the gray scale is called dynamic range of an image. Image will have high contrast, if the dynamic range is high and image will have dull washed out gray look if the dynamic range is low.

**2. What do you meant by Color model?**

A Color model is a specification of 3D-coordinates system and a subspace within that system where each color is represented by a single point.

**3. What are the types of light receptors?**

The two types of light receptors are

• Cones and

• Rods

**4. What is Chromatic Adoption?**

The hue of a perceived color depends on the adoption of the viewer. For example,the American Flag will not immediately appear red, white, and blue of the viewer has been subjected to high intensity red light before viewing the flag. The color of the flag will appear to shift in hue toward the red component cyan.

A digital image is composed of a finite number of elements each of which has a particular location or value. These elements are referred to as pixels or image elements or picture elements or pixls elements.

**6. What is geometric transformation?**

Transformation is used to alter the co-ordinate description of image.

The basic geometric transformations are

1. Image translation

2. Scaling

3. Image rotation

**7. What is meant by mach band effect?**

Mach band effect means the intensity of the stripes is constant. Therefore it preserves the brightness pattern near the boundaries, these bands are called as mach band effect.

When x, y and the amplitude values of f all are finite discrete quantities , we call the image digital image.

**9. What do you meant by Gray level?**

Gray level refers to a scalar measure of intensity that ranges from black to grays and finally to white.

Path from pixel p with co-ordinates (x, y) to pixel q with co-ordinates (s,t) is a

sequence of distinct pixels with co-ordinates.

35. Give the formula for calculating D4 and D8 distance.

D4 distance ( city block distance) is defined by

D4(p, q) = |x-s| + |y-t|

D8 distance(chess board distance) is defined by

D8(p, q) = max(|x-s|, |y-t|).