Questions tagged «segmentation»

3
如何以编程方式检测数据序列的片段以适合不同的曲线?
是否有记录在案的算法将给定数据集的各个部分分成最适合的不同曲线? 例如,大多数查看此数据图表的人都可以将其轻松分为3部分:正弦曲线段,线性段和反指数段。实际上,我是用正弦波,一条直线和一个简单的指数公式制作的。 是否存在用于查找类似零件的现有算法,然后可以将这些零件分别拟合到各种曲线/线上以形成一种最佳数据子集的复合系列? 请注意,尽管示例中段的末端几乎对齐,但这并不一定是这种情况。在分段截止时,这些值也可能突然震荡。也许这些情况将更容易发现。 更新:这是一小部分真实数据的图像: 更新2:这是一组非常小的实际数据集(仅509个数据点): 4,53,53,53,53,58,56,52,49,52,56,51,44,39,39,39,37,33,27,21,18,12,19,30,45,66,92,118,135,148,153,160,168,174,181,187,191,190,191,192,194,194,194,193,193,201,200,199,199,199,197,193,190,187,176,162,157,154,144,126,110,87,74,57,46,44,51,60,65,66,90,106,99,87,84,85,83,91,95,99,101,102,102,103,105,110,107,108,135,171,171,141,120,78,42,44,52,54,103,128,82,103,46,27,73,123,125,77,24,30,27,36,42,49,32,55,20,16,21,31,78,140,116,99,58,139,70,22,44,7,48,32,18,16,25,16,17,35,29,11,13,8,8,18,14,0,10,18,2,1,4,0,61,87,91,2,0,2,9,40,21,2,14,5,9,49,116,100,114,115,62,41,119,191,190,164,156,109,37,15,0,5,1,0,0,2,4,2,0,48,129,168,112,98,95,119,125,191,241,209,229,230,231,246,249,240,99,32,0,0,2,13,28,39,15,15,19,31,47,61,92,91,99,108,114,118,121,125,129,129,125,125,131,135,138,142,147,141,149,153,152,153,159,161,158,158,162,167,171,173,174,176,178,184,190,190,185,190,200,199,189,196,197,197,196,199,200,195,187,191,192,190,186,184,184,179,173,171,170,164,156,155,156,151,141,141,139,143,143,140,146,145,130,126,127,127,125,122,122,127,131,134,140,150,160,166,175,192,208,243,251,255,255,255,249,221,190,181,181,181,181,179,173,165,159,153,162,169,165,154,144,142,145,136,134,131,130,128,124,119,115,103,78,54,40,25,8,2,7,12,25,13,22,15,33,34,57,71,48,16,1,2,0,2,21,112,174,191,190,152,153,161,159,153,71,16,28,3,4,0,14,26,30,26,15,12,19,21,18,53,89,125,139,140,142,141,135,136,140,159,170,173,176,184,180,170,167,168,170,167,161,163,170,164,161,160,163,163,160,160,163,169,166,161,156,155,156,158,160,150,149,149,151,154,156,156,156,151,149,150,153,154,151,146,144,149,150,151,152,151,150,148,147,144,141,137,133,130,128,128,128,136,143,159,180,196,205,212,218,222,225,227,227,225,223,222,222,221,220,220,220,220,221,222,223,221,223,225,226,227,228,232,235,234,236,238,240,241,240,239,237,238,240,240,237,236,239,238,235 这,绘制,与appoximate的位置有些已知的真实世界元素边用虚线标记,奢侈品,我们通常不会有: 然而,我们确实拥有的一种奢望是事后观察:就我而言,数据不是时间序列,而是与空间相关的。一次分析整个数据集(通常为5000-15000个数据点)是有意义的,而不是持续进行。

3
语义分割的损失函数
对于滥用技术术语表示赞赏。我正在通过卷积神经网络(CNN)进行语义分割的项目;试图实现Encoder-Decoder类型的体系结构,因此输出的大小与输入的大小相同。 您如何设计标签?一个应该应用什么损失函数?尤其是在严重的类别不平衡的情况下(但是类别之间的比率在图像之间是可变的)。 该问题涉及两个类别(感兴趣的对象和背景)。我正在将Keras与tensorflow后端一起使用。 到目前为止,我将应用按像素标注将预期输出设计为与输入图像相同的尺寸。模型的最后一层具有softmax激活(针对2个类)或S型激活(表示像素属于对象类的概率)。我在为此类任务设计合适的目标函数时遇到麻烦: function(y_pred,y_true), 同意Keras的观点。 请尝试具体说明所涉及的张量的大小(模型的输入/输出)。任何想法和建议都非常感谢。谢谢 !
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