cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgb (Operator)


cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgb — Convert a single-channel color filter array image into an RGB image.


cfa_to_rgb(CFAImage : RGBImage : CFAType, Interpolation : )

Herror cfa_to_rgb(const Hobject CFAImage, Hobject* RGBImage, const char* CFAType, const char* Interpolation)

Herror T_cfa_to_rgb(const Hobject CFAImage, Hobject* RGBImage, const Htuple CFAType, const Htuple Interpolation)

void CfaToRgb(const HObject& CFAImage, HObject* RGBImage, const HTuple& CFAType, const HTuple& Interpolation)

HImage HImage::CfaToRgb(const HString& CFAType, const HString& Interpolation) const

HImage HImage::CfaToRgb(const char* CFAType, const char* Interpolation) const

HImage HImage::CfaToRgb(const wchar_t* CFAType, const wchar_t* Interpolation) const   (Windows only)

static void HOperatorSet.CfaToRgb(HObject CFAImage, out HObject RGBImage, HTuple CFAType, HTuple interpolation)

HImage HImage.CfaToRgb(string CFAType, string interpolation)


cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgbCfaToRgb converts a single-channel color filter array image CFAImageCFAImageCFAImageCFAImageCFAImage into an RGB image RGBImageRGBImageRGBImageRGBImageRGBImage. Color filter array images are typically generated by single-chip CCD cameras. The conversion from color filter array image to RGB image is typically done on the camera itself or is performed by the device driver of the frame grabber that is used to grab the image. In some cases, however, the device driver simply passes the color filter array image through unchanged. In this case, the corresponding HALCON frame grabber interface typically converts the image into an RGB image. Hence, the operator cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgbCfaToRgb is normally used if the images are not being grabbed using the HALCON frame grabber interface (grab_imagegrab_imageGrabImageGrabImageGrabImage or grab_image_asyncgrab_image_asyncGrabImageAsyncGrabImageAsyncGrabImageAsync), but are grabbed using function calls from the frame grabber SDK, and are passed to HALCON using gen_image1gen_image1GenImage1GenImage1GenImage1 or gen_image1_externgen_image1_externGenImage1ExternGenImage1ExternGenImage1Extern.

In single-chip CCD cameras, a color filter array in front of the sensor provides (subsampled) color information. The most frequently used filter is the so-called Bayer filter. The color filter array has the following layout in this case: Each gray value of the input image CFAImageCFAImageCFAImageCFAImageCFAImage corresponds to the brightness of the pixel behind the corresponding color filter. Hence, in the above layout, the pixel (0,0) corresponds to a green color value, while the pixel (0,1) corresponds to a blue color value. The layout of the Bayer filter is completely determined by the first two elements of the first row of the image, and can be chosen with the parameter CFATypeCFATypeCFATypeCFATypeCFAType. In particular, this enables the correct conversion of color filter array images that have been cropped out of a larger image (e.g., using crop_partcrop_partCropPartCropPartCropPart or crop_rectangle1crop_rectangle1CropRectangle1CropRectangle1CropRectangle1).

The algorithm that is used to interpolate the RGB values is determined by the parameter InterpolationInterpolationInterpolationInterpolationinterpolation. For InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear'"bilinear""bilinear""bilinear""bilinear", a bilinear interpolation is performed. While this algorithm is very fast, it typically leads to “zipper-like” artifacts and color artifacts at strong edges. For InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear_dir'"bilinear_dir""bilinear_dir""bilinear_dir""bilinear_dir", a modified version of the bilinear interpolation is performed that may lead to fewer zipper-like artifacts, especially at horizontal or vertical edges in the image. The results may still exhibit color artifacts at strong edges, however. The runtime of this algorithm is only slightly longer than that of bilinear interpolation. For InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear_enhanced'"bilinear_enhanced""bilinear_enhanced""bilinear_enhanced""bilinear_enhanced", an enhanced version of the bilinear interpolation is performed that produces fewer zipper-like artifacts and color artifacts than the other two bilinear algorithms in most cases. The runtime of this algorithm is significantly longer than that of the other two algorithms.

If 'mmx_enable'"mmx_enable""mmx_enable""mmx_enable""mmx_enable" is set to 'true'"true""true""true""true" (and the SIMD instruction set is available), the internal calculations for byte images are performed using SIMD technology for InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear'"bilinear""bilinear""bilinear""bilinear" and InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear_dir'"bilinear_dir""bilinear_dir""bilinear_dir""bilinear_dir".

For InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear'"bilinear""bilinear""bilinear""bilinear" and InterpolationInterpolationInterpolationInterpolationinterpolation = 'bilinear_dir'"bilinear_dir""bilinear_dir""bilinear_dir""bilinear_dir", cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgbCfaToRgb can be executed on OpenCL devices. The width of the input image should be a multiple of four for byte images, or two for uint2 images, as the operation will be much slower otherwise.

Execution Information


CFAImageCFAImageCFAImageCFAImageCFAImage (input_object)  singlechannelimage(-array) objectHImageHImageHobject (byte* / uint2*) *allowed for compute devices

Input image.

RGBImageRGBImageRGBImageRGBImageRGBImage (output_object)  multichannel-image(-array) objectHImageHImageHobject * (byte / uint2)

Output image.

CFATypeCFATypeCFATypeCFATypeCFAType (input_control)  string HTupleHTupleHtuple (string) (string) (HString) (char*)

Color filter array type.

Default value: 'bayer_gb' "bayer_gb" "bayer_gb" "bayer_gb" "bayer_gb"

List of values: 'bayer_bg'"bayer_bg""bayer_bg""bayer_bg""bayer_bg", 'bayer_gb'"bayer_gb""bayer_gb""bayer_gb""bayer_gb", 'bayer_gr'"bayer_gr""bayer_gr""bayer_gr""bayer_gr", 'bayer_rg'"bayer_rg""bayer_rg""bayer_rg""bayer_rg"

InterpolationInterpolationInterpolationInterpolationinterpolation (input_control)  string HTupleHTupleHtuple (string) (string) (HString) (char*)

Interpolation type.

Default value: 'bilinear' "bilinear" "bilinear" "bilinear" "bilinear"

List of values: 'bilinear'"bilinear""bilinear""bilinear""bilinear", 'bilinear_dir'"bilinear_dir""bilinear_dir""bilinear_dir""bilinear_dir", 'bilinear_enhanced'"bilinear_enhanced""bilinear_enhanced""bilinear_enhanced""bilinear_enhanced"


cfa_to_rgbcfa_to_rgbCfaToRgbCfaToRgbCfaToRgb returns 2 (H_MSG_TRUE) if all parameters are correct. If the input is empty the behavior can be set via set_system(::'no_object_result', <Result>:)set_system("no_object_result", <Result>)SetSystem("no_object_result", <Result>)SetSystem("no_object_result", <Result>)SetSystem("no_object_result", <Result>). If necessary, an exception is raised.

Possible Predecessors

gen_image1_externgen_image1_externGenImage1ExternGenImage1ExternGenImage1Extern, gen_image1gen_image1GenImage1GenImage1GenImage1, grab_imagegrab_imageGrabImageGrabImageGrabImage

Possible Successors


See also