# Documentation

### This is machine translation

Translated by
Mouseover text to see original. Click the button below to return to the English version of the page.

# isEpipoleInImage

Determine whether image contains epipole

## Syntax

``isIn = isEpipoleInImage(F,imageSize)``
``isIn = isEpipoleInImage(F',imageSize)``
``````[isIn,epipole] = isEpipoleInImage(___)``````

## Description

````isIn = isEpipoleInImage(F,imageSize)` determines whether the first stereo image associated with the fundamental matrix `F` contains an epipole. `imageSize` is the size of the first image, and is in the format returned by the function `size`.```
````isIn = isEpipoleInImage(F',imageSize)` determines whether the second stereo image associated with the fundamental matrix `F`' contains an epipole.```
``````[isIn,epipole] = isEpipoleInImage(___)``` also returns the epipole. ```

## Input Arguments

`F`

A 3-by-3 fundamental matrix computed from stereo images. `F` must be double or single. If P1 represents a point in the first image I1 that corresponds to P2, a point in the second image I2, then:

 [P2,1] * `F` * [P1,1]’ = 0

In computer vision, the fundamental matrix is a 3-by-3 matrix which relates corresponding points in stereo images. When two cameras view a 3-D scene from two distinct positions, there are a number of geometric relations between the 3-D points and their projections onto the 2-D images that lead to constraints between the image points. Two images of the same scene are related by epipolar geometry.

`imageSize`

The size of the image, and in the format returned by the function `size`.

## Output Arguments

 `isIn` Logical value set to `true` when the image contains an epipole, and set to `false` when the image does not contain an epipole. When the image planes are at a great enough angle to each other, you can expect the epipole to be located in the image. When the image planes are at a more subtle angle to each other, you can expect the epipole to be located outside of the image, (but still in the image plane). `epipole` A 1-by-2 vector indicating the location of the epipole.

## Examples

collapse all

```% Load stereo point pairs. load stereoPointPairs f = estimateFundamentalMatrix(matchedPoints1, matchedPoints2, 'NumTrials', 2000); imageSize = [200 300]; % Determine whether the image contains epipole and epipole location. [isIn,epipole] = isEpipoleInImage(f,imageSize) ```
```isIn = logical 1 epipole = 256.5465 100.0140 ```
``` f = [0 0 1; 0 0 0; -1 0 0]; imageSize = [200, 300]; [isIn,epipole] = isEpipoleInImage(f',imageSize) ```
```isIn = logical 0 epipole = 1.0e+308 * 0 1.7977 ```