Automatic medical image segmentation based on gradient vector flow 結(jié)合對心臟序列圖像的分割
Detection of motion - target based on improved gradient vector flow snake model 基于改進(jìn)梯度向量流形變模型的動目標(biāo)檢測方法
We discuss several different definitions of directional derivative and gradient vector 摘要討論了幾種不同的方向?qū)?shù)和梯度的定義。
The gradient vector can be used to construct the initial errors 這時可以對梯度向量本身進(jìn)行分析,或者用這個梯度向量構(gòu)造初始誤差場。
Adjoint method provides an efficient tool to calculate the gradient vector of the cost function to the initial field 利用伴隨方法,可以求出該度量函數(shù)關(guān)于初始場的梯度向量。
Therefore the gvf ( gradient vector field ) is used to substitute the traditional potential field and it overcomes the defects of the traditional active contour 于是,我們采用一種梯度向量流場作為外力,從而有效地克服了傳統(tǒng)勢能場的弱點(diǎn),給曲線的移動以很好的指向。
When using modem optimization methods , the gradient vector information of the target function is not necessary , so there is much flexible in solving complex optimization problems 使用現(xiàn)代優(yōu)化技術(shù)時不需要目標(biāo)函數(shù)的梯度向量,因此在解決復(fù)雜優(yōu)化問題時有更大的靈活性。
2 . study the working principle of the vector transducer , mainly for two - dimensional pressure - gradient transducer . and the experimental results for directional pattern of two - dimensional pressure - gradient vector transducer at frequency 3khz and 5khz are given 重點(diǎn)對本文所要研究的壓差式矢量水聽器進(jìn)行研究,并運(yùn)用消聲水池實(shí)測數(shù)據(jù)繪出了二維壓差式矢量水聽器在3khz和5khz下的指向性圖。
To corner feature , both gradient magnitude change and direction change of gradient vector are discontinuity in a local image neighborhood , hence gradient - direction variation and gradient magnitude are used as another decision rule of the corner detection to improve antinoise 為了提高抗噪聲,根據(jù)角特征不僅灰度變化是不連續(xù)的,且相對周圍其他點(diǎn)的梯度方向也是不連續(xù)的,提出利用梯度角變化和梯度幅值作為角特征檢測的另一個準(zhǔn)則。
There are two methods to optimize the parameters and structures of neuro - fuzzy networks : one is the differential coefficient optimization method based on gradient vector ; the other is based on modern optimization methods , such as genetic methods , simulated annealing etc , in which , the researches on genetic methods are most prominent 目前,對模糊神經(jīng)網(wǎng)絡(luò)的權(quán)值或結(jié)構(gòu)進(jìn)行優(yōu)化的方法有兩類:一類是基于梯度向量的導(dǎo)數(shù)優(yōu)化方法;第二類方法是基于現(xiàn)代最優(yōu)化技術(shù)的非導(dǎo)數(shù)優(yōu)化方法,如遺傳算法、模擬退火算法等,其中以遺傳算法的研究最為突出。