What is an area table?

What is an area table?

A summed-area table is a data structure and algorithm for quickly and efficiently generating the sum of values in a rectangular subset of a grid. In computer vision it was popularized by Lewis and then given the name “integral image” and prominently used within the Viola–Jones object detection framework in 2001.

How do you find the integral of an image?

The integral image of a region at the point (x,y) in the summed area table is the sum of all pixels above and to the left of (x,y) including i(x,y), according to equation (1), where i(x,y) is the value of the pixel at the position (x,y).

What is the use of integral image?

The Integral Image is used as a quick and effective way of calculating the sum of values (pixel values) in a given image – or a rectangular subset of a grid (the given image). It can also, or is mainly, used for calculating the average intensity within a given image.

What is integral image in Viola Jones?

An Integral Image is an intermediate representation of an image where the value for location (x, y) on the integral image equals the sum of the pixels above and to the left (inclusive) of the (x, y) location on the original image (Viola & Jones, 2001).

What is the area of rectangle formula?

The area A of a rectangle is given by the formula, A=lw , where l is the length and w is the width. Given that, the area is 500 square feet and the width is 20 feet.

What is integral image used for?

Why do we need integral images?

Integral images facilitate summation of pixels and can be performed in constant time, regardless of the neighborhood size. The following figure illustrates the summation of a subregion of an image, you can use the corresponding region of its integral image.

What does box filter do?

Box filtering is basically an average-of-surrounding-pixel kind of image filtering. The power of box filtering is one can write a general image filter that can do sharpen, emboss, edge-detect, smooth, motion-blur, etcetera. Provided approriate filter kernel is used.

What is integral image in face detection?

Integral Images An Integral Image is an intermediate representation of an image where the value for location (x, y) on the integral image equals the sum of the pixels above and to the left (inclusive) of the (x, y) location on the original image (Viola & Jones, 2001).