Pixel Containers and Files

Pixel Container Definition

Image Objects

The eVision image objects contain image data that represents rectangular images.

Each image object has a data buffer, accessible via a pointer, where pixel values are stored contiguously, row by row.

Image Main Parameters

The rectangular array of pixels of an eVision image object is characterized by the EBaseROI ^{.NET Python} parameters:

• The EBaseROI::GetWidth ^{.NET Python} is the number of pixels per row of the image.

• The EBaseROI::GetHeight ^{.NET Python} is the number of rows of the image.

• The EBaseROI::SetSize ^{.NET Python} allow to set both the EBaseROI::GetWidth ^{.NET Python} and EBaseROI::GetHeight ^{.NET Python}.

• The EBaseROI::GetBitsPerPixel ^{.NET Python} is the number of storage bits per pixel.

• The EBaseROI::GetRowPitch ^{.NET Python} is the number of bytes between two vertically adjacent pixels. It is always bigger than Width × (BitsPerPixel / 8).

Warning

• The maximum size for the row pitch and the height are 2,147,483,647 (2³¹-1).\

• The maximum size for the width is the maximum size for the row pitch divided by the number of storage bytes per pixel (8 × BitsPerPixel).

• The EPlaneCropper::GetPlane ^{.NET Python} contains the number of color components.

  • For gray-level images: EPlaneCropper::GetPlane ^{.NET Python} = 1

  • For color images: EPlaneCropper::GetPlane ^{.NET Python} = 3

Classes

The image and ROI classes derive from the abstract class EBaseROI ^{.NET Python} and inherit all its properties.

EBaseROI inheritance.

See also

For the enumeration of the available types, see EImageType ^{.NET Python} Enum.

eVision supports the following image types according to their pixel types.

eVision	Genicam PNFC	Definition	Class
BW8	Mono8	8-bit grayscale image (each pixel is stored in 1 byte).	EImageBW8 .NET Python
BW16	Mono16	16-bit grayscale image (each pixel is stored in 2 bytes).	EImageBW16 .NET Python
BW32	Mono32	32-bit grayscale image (each pixel is stored in 4 bytes).	EImageBW32 .NET Python
BW32f	x	Gray-level pixel value, coded as a 32-bit floating-point number (each pixel is stored in 4 bytes).	EImageBW32f .NET Python
C24	RGB8	24-bit color image (each pixel is stored in 3 bytes). Compatible with Microsoft® Windows RGB24 color images.	EImageC24 .NET Python
C24A	RGBa8	32-bit color image (each pixel is stored in 4 bytes). Compatible with Microsoft® Windows RGB32 color images.	EImageC24A .NET Python
C48	RGB16	48-bit color image (each pixel is stored in 6 bytes). Compatible with Microsoft® Windows RGB48 color images.	EImageC48 .NET Python

Note

Easy::GetBestMatchingImageType ^{.NET Python} returns the best matching image type for a given file on disk.

Depth Maps

A depth map represents a 3D object using a 2D grayscale image in which each pixel represents a 3D point.

• The pixel coordinates are the X and Y coordinates of the point.

• The gray value of the pixel is a representation of the Z coordinate of the point.

Basic Depth map concept.

eVision	Genicam PNFC	Definition	Class
EDepth8	Coord3D_C8	8-bit depth map (each pixel is stored in 1 byte as an integer)	EDepthMap8 .NET Python
EDepth16	Coord3D_C16	16-bit depth map (each pixel is stored in 2 bytes as a fixed point)	EDepthMap16 .NET Python
EDepth32f	Coord3D_C32f	32-bit depth map (each pixel is stored in 4 bytes as a float)	EDepthMap32f .NET Python

Note

8 and 16-bit depth map values are stored in buffers compatible with the 2D eVision images.

Point Clouds

A point cloud is an unstructured set of 3D points representing discrete positions on the surface of an object.

The point clouds are produced by various 3D scanning techniques, such as laser triangulation, time of flight or structured lighting.

For details, see, for example, en.wikipedia.org/wiki/Point_cloud.

Basic Point cloud concept.

eVision	Genicam PNFC	Definition	Class
Point Cloud	Coord3D_ABC32	Set of points coordinates (each coordinate is stored in 4 bytes as a float)	EPointCloud .NET Python

Supported Image File Types

See also

For the enumeration of the available types, see EImageFileType ^{.NET Python} Enum.

Type	Description
BMP	Uncompressed image data format (Windows Bitmap Format).
JPEG	A lossy data compression standard issued by the Joint Photographic Expert Group registered as ISO/IEC 10918-1. The compression irretrievably loses quality.
JFIF	JPEG File Interchange Format.
JPEG-2000	A data compression standard issued by the Joint Photographic Expert Group registered as ISO/IEC 15444-1 and ISO/IEC 15444-2. eVision supports only lossy compression format, file format and code stream variants. The code stream describes the image samples. The file format includes meta-information such as the image resolution and color space.
PNG	Lossless data compression method (Portable Network Graphics).
Serialized	The Euresys proprietary image file format obtained from the serialization of eVision image objects.
TIFF	The Tag Image File Format is currently controlled by Adobe Systems and uses the LibTIFF third-party library to process images written for the 5.0 or 6.0 TIFF specification. The file save operations are lossless and save the images without any compression. The file load operations support all the TIFF variants listed in the LibTIFF specification.

Warning

Some image file types may contain EXIF metadata indicating the orientation or cropping of the image. These metadata are not taken into consideration when opening an image.

Color Types

eVision supports the following color systems:

Type	Description
EISH .NET Python	Intensity, Saturation, Hue
ELAB .NET Python	CIE Lightness, a*, b*
ELCH .NET Python	Lightness, Chroma, Hue
ELSH .NET Python	Lightness, Saturation, Hue
ELUV .NET Python	CIE Lightness, u*, v*
ERGB .NET Python	NTSC/PAL/SMPTE Red, Green, Blue
EVSH .NET Python	Value, Saturation, Hue
EXYZ .NET Python	CIE XYZ
EYIQ .NET Python	CCIR Luma, Inphase, Quadrature
EYSH .NET Python	CCIR Luma, Saturation, Hue
EYUV .NET Python	CCIR Luma, U Chroma, V Chroma

Pixel and File Types Compatibility

For the compatible combinations in the following table, the image integrity is preserved with no data loss (except from JPEG and JPEG2000 with lossy compression).

The other combinations are not supported and an exception occurs if you use them.

Type	BMP	JPEG	JPEG2000	PNG	TIFF	Serialized
BW8	✓	✓	✓	✓	✓	✓
BW16	–	–	✓	✓	✓ ¹	✓
BW32	–	–	–	–	✓ ¹	✓
BW32f	–	–	–	–	–	✓
C24	✓	✓	✓	✓	✓	✓
C24A	✓	–	–	✓	–	✓
C48	–	–	–	✓	✓ ¹	✓
Depth8	✓	✓	✓	✓	✓	✓
Depth16	–	–	✓	✓	✓ ¹	✓
Depth32f	–	–	–	–	–	✓

• ✓ ¹ : BW16 and BW32 are not supported by Baseline TIFF readers.