Coreimage.framework

Framework

Core Image

Use built-in or custom filters to process still and video images in near real-time. Detect features such as faces and eyes, and track faces in video images.

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Overview

Core Image is an image processing and analysis technology designed to provide high-performance processing for still and video images.

Getting Started with Core Image

Use Core Image classes to:

• Process images using the many built-in image filters

• Chain together filters and then archive them for later use

• Detect features (such as faces and eyes) in still and video images, and track faces in video images

• Analyze images to get a set of auto adjustment filters

• Create custom filters for use in your app

In OS X, you can also package custom filters as Image Units that you can publish for use by others. For details, see Image Unit Tutorial.

To learn about using Core Image, read Core Image Programming Guide.

Classes

CIColor

The CIColor class contains color values and the color space for which the color values are valid. You use CIColor objects in conjunction with other Core Image classes, such as  CIFilter, CIContext,and CIImage, to take advantage of the built-in Core Image filters when processing images.

CIColorKernel

A CIColorKernel object manages a GPU-based image processing routine that processes only the color information in images, used to create custom Core Image filters. You create CIColorKernel objects using methods of the superclass CIKernel.

CIContext

The CIContext class provides an evaluation context for rendering a CIImage object through Quartz 2D, Metal, or OpenGL. You use CIContext objects in conjunction with other Core Image classes, such as CIFilter, CIImage, and CIColor, to process images using Core Image filters.

CIDetector

A CIDetector object uses image processing to search for and identify notable features (faces, rectangles, and barcodes) in a still image or video. Detected features are represented by CIFeature objects that provide more information about each feature.

CIFaceFeature

A CIFaceFeature object describes a face detected in a still or video image. Its properties provide information about the face’s eyes and mouth. A face object in a video can also have properties that track its location over time—tracking ID and frame count. 

CIFeature

A CIFeature object represents a portion of an image that a detector believes matches its criteria. Subclasses of CIFeature typically hold additional information specific to the detector that discovered the feature.

CIFilter

The CIFilter class produces a CIImage object as output. Typically, a filter takes one or more images as input. Some filters, however, generate an image based on other types of input parameters. The parameters of a CIFilter object are set and retrieved through the use of key-value pairs.

CIFilterGenerator

The CIFilterGenerator class provides methods for creating a CIFilter object by chaining together existing CIFilter objects to create complex effects. (A filter chain refers to the CIFilter objects that are connected in the CIFilterGenerator object.) The complex effect can be encapsulated as a CIFilterGenerator object and saved as a file so that it can be used again. The filter generator file contains an archived instance of all the CIFilter objects that are chained together. 

CIFilterShape

The CIFilterShape class describes the bounding shape of a filter and the domain of definition (DOD) of a filter operation. You use CIFilterShape objects in conjunction with Core Image classes, such as CIFilter, CIKernel, and CISampler, to create custom filters.

CIImage

The CIImage class represents an image. Core Image images are immutable. You use CIImage objects in conjunction with other Core Image classes—such as CIFilter, CIContext, CIVector, and CIColor—to take advantage of the built-in Core Image filters when processing images. You can create CIImage objects with data supplied from a variety of sources, including Quartz 2D images, Core Video image buffers (CVImageBufferRef), URL-based objects, and NSData objects.

CIImageAccumulator

The CIImageAccumulator class enables feedback-based image processing for such things as iterative painting operations or fluid dynamics simulations. You use CIImageAccumulator objects in conjunction with other Core Image classes, such as  CIFilter, CIImage, CIVector, and CIContext, to take advantage of the built-in Core Image filters when processing images.

CIKernel

An CIKernel object manages a GPU-based image processing routine used to create custom Core Image filters. To ensure the best performance, use the subclasses CIColorKernel and CIWarpKernelwhen implementing filters that operate only on color or geometry information, and use the CIKernel class directly only when implementing general-purpose filters that use both color and geometry information together.

CIPlugIn

The CIPlugIn class loads image units. An image unit is an image processing bundle that contains one or more Core Image filters. The .plugin extension indicates one or more filters that are packaged as an image unit.

CIQRCodeFeature

A CIQRCodeFeature describes a Quick Response code (a two-dimensional barcode using the ISO/IEC 18004:2006 standard) detected in a video or still image. The properties of a QR code feature identify the corners of the barcode as it appears in perspective in the image and provide the message decoded from the barcode.

CIRectangleFeature

A CIRectangleFeature object describes a quadrilateral region detected in a video or still image. A detected rectangle feature is not necessarily rectangular in the plane of the image; rather, the feature identifies a shape that may be rectangular in space but which appears in perspective in the image—for example, a paper or book on a desk. The properties of a rectangle feature identify its corners in image coordinates.

CISampler

The CISampler class retrieves samples of images for processing by a CIKernel object. A CISampler object defines a coordinate transform, and modes for interpolation and wrapping. You use CISampler objects in conjunction with other Core Image classes, such as  CIFilter, CIKernel, and CIFilterShape, to create custom filters.

CITextFeature

A CITextFeature object describes a quadrilateral region likely to contain upright text detected in a video or still image. The properties of a text feature identify its corners in image coordinates.

CIVector

The CIVector class is used for coordinate values and direction vectors. You typically use a CIVector object to pass parameter values to Core Image filters. CIVector objects work in conjunction with other Core Image classes, such as CIFilter, CIContext, CIImage, and CIColor, to process images using the Core Image framework.

CIWarpKernel

A CIWarpKernel object manages a GPU-based image processing routine that processes only the geometry information in an image, used to create custom Core Image filters. You create CIWarpKernel objects using methods of the superclass CIKernel.

Protocols

CIFilterConstructor

The CIFilterConstructor protocol defines a method for supplying CIFilter objects.

CIImageProcessorInput

A object conforming to the CIImageProcessorInput protocol provides image data and information for use in a custom image processor. Your app does not define classes that adopt this protocol; Core Image provides an object of this type when you create a custom image processor with a block passed to the CIImageimageWithExtent:processorDescription:argumentDigest:inputFormat:outputFormat:options:roiCallback:processor:method.

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CIImageProcessorOutput

A object conforming to the CIImageProcessorOutput protocol provides image data and information for use in a custom image processor. Your app does not define classes that adopt this protocol; Core Image provides an object of this type when you create a custom image processor with a block passed to the CIImageimageWithExtent:processorDescription:argumentDigest:inputFormat:outputFormat:options:roiCallback:processor:method.

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CIPlugInRegistration

The CIPlugInRegistration protocol defines a method for loading Core Image image units. The principal class of an image unit bundle must support this protocol.