highpass_imagehighpass_imageHighpassImageHighpassImagehighpass_image (算子)

名称

highpass_imagehighpass_imageHighpassImageHighpassImagehighpass_image — 从图像中提取高频分量。

签名

highpass_image(Image : Highpass : Width, Height : )

描述

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image extracts high frequency components in an image by applying a linear filter with the following matrix (in case of a 7x5 matrix): 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 -35 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 This corresponds to applying a mean operator (mean_imagemean_imageMeanImageMeanImageMeanImagemean_image), and then subtracting the original gray value. For byte images, a value of 128 is added to the result, i.e., zero crossings occur for 128. Correspondingly for uint2 images, 32767 is added.

This filter emphasizes high frequency components (edges and corners). The cutoff frequency is determined by the size (Height x Width) of the filter matrix: the larger the matrix, the smaller the cutoff frequency is.

At the image borders the pixels' gray values are mirrored. In case of over- or underflow the gray values are clipped (255 and 0, resp.).

注意

If even values are passed for HeightHeightHeightHeightheightheight or WidthWidthWidthWidthwidthwidth, the operator uses the next larger odd value instead. Thus, the center of the filter mask is always uniquely determined.

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image 可在 OpenCL 设备上执行。 The same limitations as for mean_imagemean_imageMeanImageMeanImageMeanImagemean_image and sub_imagesub_imageSubImageSubImageSubImagesub_image apply.

请注意，若使用域缩减后的图像作为输入，滤波器算子可能会返回意外结果。请参阅滤波器一章

执行信息

支持 OpenCL 计算设备。
多线程类型：可重入（与非独占算子并行运行）。
多线程作用域：全局（可从任何线程调用）。
在元组级别上自动并行化。
在通道级别上自动并行化。
在域级别上自动并行化。

参数

ImageImageImageImageimageimage (输入对象) (multichannel-)image(-array) → object (byte* / uint2*) *允许用于计算设备

输入图像。

HighpassHighpassHighpassHighpasshighpasshighpass (输出对象) (multichannel-)image(-array) → object (byte / uint2)

High-pass-filtered result image.

WidthWidthWidthWidthwidthwidth (输入控制) extent.x → (integer)

Width of the filter mask.

默认值： 9

建议值： 3, 5, 7, 9, 11, 13, 17, 21, 29, 41, 51, 73, 101

值范围： 1 ≤ Width Width Width Width width width

最小增量： 2

建议增量： 2

HeightHeightHeightHeightheightheight (输入控制) extent.y → (integer)

Height of the filter mask.

默认值： 9

建议值： 3, 5, 7, 9, 11, 13, 17, 21, 29, 41, 51, 73, 101

值范围： 1 ≤ Height Height Height Height height height

最小增量： 2

建议增量： 2

示例（C）

highpass_image(Image,&Highpass,7,5);
threshold(Highpass,&Region,60.0,255.0);
skeleton(Region,&Skeleton);

结果

highpass_imagehighpass_imageHighpassImageHighpassImageHighpassImagehighpass_image 在所有参数正确时返回 2 ( H_MSG_TRUE )。如果输入为空则可设置行为通过 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>)set_system("no_object_result",<Result>)。如有必要，则抛出异常。

可能的后继

thresholdthresholdThresholdThresholdThresholdthreshold, skeletonskeletonSkeletonSkeletonSkeletonskeleton

替代

mean_imagemean_imageMeanImageMeanImageMeanImagemean_image, sub_imagesub_imageSubImageSubImageSubImagesub_image, convol_imageconvol_imageConvolImageConvolImageConvolImageconvol_image, bandpass_imagebandpass_imageBandpassImageBandpassImageBandpassImagebandpass_image

另见

dyn_thresholddyn_thresholdDynThresholdDynThresholdDynThresholddyn_threshold

模块

基础

算子