Class LeapInternal::Image

class LeapInternal.Image

The Image class represents a stereo image pair from the Leap Motion device.

In addition to image data, the Image object provides a distortion map for correcting lens distortion.

Since

2.1.0

Public Types

enum FormatType

Enumerates the possible image formats.

The Image.Format() function returns an item from the FormatType enumeration.

Since

2.2.0

Values:

INFRARED

IBRG

Public Functions

byte[] Data (CameraType camera)

The buffer containing the image data.

The image data is a set of 8-bit intensity values. The buffer is image.Width * image.Height * image.BytesPerPixel bytes long.

Use the ByteOffset method to find the beginning offset of the data for the specified camera.

Since

4.0

UInt32 ByteOffset (CameraType camera)

The offset, in number of bytes, from the beginning of the Data() buffer to the first byte of the image data for the specified camera.

Since

4.0

float[] Distortion (CameraType camera)

The distortion calibration map for this image.

The calibration map is a 64x64 grid of points. Each point is defined by a pair of 32-bit floating point values. Each point in the map represents a ray projected into the camera. The value of a grid point defines the pixel in the image data containing the brightness value produced by the light entering along the corresponding ray. By interpolating between grid data points, you can find the brightness value for any projected ray. Grid values that fall outside the range [0..1] do not correspond to a value in the image data and those points should be ignored.

The calibration map can be used to render an undistorted image as well as to find the true angle from the camera to a feature in the raw image. The distortion map itself is designed to be used with GLSL shader programs. In other contexts, it may be more convenient to use the Image Rectify() and Warp() functions.

Distortion is caused by the lens geometry as well as imperfections in the lens and sensor window. The calibration map is created by the calibration process run for each device at the factory (and which can be rerun by the user).

Since

2.1.0

UnityEngine.Vector3 PixelToRectilinear (CameraType camera, UnityEngine.Vector3 pixel)

Provides the corrected camera ray intercepting the specified point on the image.

Given a point on the image, PixelToRectilinear() corrects for camera distortion and returns the true direction from the camera to the source of that image point within the Leap Motion field of view.

This direction vector has an x and y component [x, y, 1], with the third element always one. Note that this vector uses the 2D camera coordinate system where the x-axis parallels the longer (typically horizontal) dimension and the y-axis parallels the shorter (vertical) dimension. The camera coordinate system does not correlate to the 3D Leap Motion coordinate system.

Note: This function should be called immediately after an image is obtained. Incorrect results will be returned if the image orientation has changed or a different device is plugged in between the time the image was received and the time this function is called.

Note, this function was formerly named Rectify().

UnityEngine.Vector3 RectilinearToPixel (CameraType camera, UnityEngine.Vector3 ray)

Provides the point in the image corresponding to a ray projecting from the camera.

Given a ray projected from the camera in the specified direction, RectilinearToPixel() corrects for camera distortion and returns the corresponding pixel coordinates in the image.

The ray direction is specified in relationship to the camera. The first vector element corresponds to the “horizontal” view angle; the second corresponds to the “vertical” view angle.

The RectilinearToPixel() function returns pixel coordinates outside of the image bounds if you project a ray toward a point for which there is no recorded data.

RectilinearToPixel() is typically not fast enough for realtime distortion correction. For better performance, use a shader program executed on a GPU.

Note: This function should be called immediately after an image is obtained. Incorrect results will be returned if the image orientation has changed or a different device is plugged in between the time the image was received and the time this function is called.

Note, this function was formerly named Warp().

bool Equals (Image other)

Compare Image object equality.

Two Image objects are equal if and only if both Image objects represent the exact same Image and both Images are valid.

Since

2.1.0

override string ToString ()

A string containing a brief, human readable description of the Image object.

Since

2.1.0

float RayOffsetX (CameraType camera)

The horizontal ray offset for a particular camera.

Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].

Since

4.0

float RayOffsetY (CameraType camera)

The vertical ray offset for a particular camera.

Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].

Since

2.1.0

float RayScaleX (CameraType camera)

The horizontal ray scale factor for a particular camera.

Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].

Since

2.1.0

float RayScaleY (CameraType camera)

The vertical ray scale factor for a particular camera.

Used to convert between normalized coordinates in the range [0..1] and the ray slope range [-4..4].

Since

2.1.0

Properties

UInt32 DeviceID { get; set; }

Returns a convenience device ID based on which attached device sent this image.

Since

4.5.0

UInt32 NumBytes { get; set; }

The number of bytes in the Data() buffer corresponding to each image. Use the ByteOffset() function to find the starting byte offset for each image.

Since

4.0

Int64 SequenceId { get; set; }

The image sequence ID.

Since

2.2.1

int Width { get; set; }

The image width.

Since

2.1.0

int Height { get; set; }

The image height.

Since

2.1.0

int BytesPerPixel { get; set; }

The number of bytes per pixel.

Use this value along with Image.Width() and Image.Height() to calculate the size of the data buffer.

Since

2.2.0

FormatType Format { get; set; }

The image format.

Since

2.2.0

int DistortionWidth { get; set; }

The stride of the distortion map.

Since each point on the 64x64 element distortion map has two values in the buffer, the stride is 2 times the size of the grid. (Stride is currently fixed at 2 * 64 = 128).

Since

2.1.0

int DistortionHeight { get; set; }

The distortion map height. Currently fixed at 64.

Since

2.1.0

Int64 Timestamp { get; set; }

Returns a timestamp indicating when this frame began being captured on the device.

Since

2.2.7