摘要
传统的绝对相位提取技术通常需要多帧附加编码图案来辅助识别条纹级次,从而导致了投影效率的降低。因此,提出了一种基于归一化调制度解调的绝对相位提取方法。首先利用空分复用技术建立查找表指定与条纹顺序一一对应的唯一码字序列,然后将相移正弦条纹作为载频条纹直接将该码字调制到振幅强度上形成空分复用的组合相移条纹。当该组合相移条纹投影到待测物体上,可从采集的组合变形条纹同时解调出包裹相位和调制强度,再对调制强度做归一化处理,既能有效抑制反射率不均匀影响,也能解调出可定位条纹级次的四灰度码字,实现了无需附加编码图案的绝对相位提取。为了提高多级灰度码字提取的鲁棒性,利用图像形态学处理操作来分割图像的灰度,并提出了一种半周期连通域码字纠正方法。实验结果验证了所提方法的可行性和有效性。
Conventional absolute phase extraction techniques typically require multiple frames of additional coded patterns to assist in fringe order recognition,reducing the effectiveness of the projection.Therefore,an absolute phase extraction method based on normalized modulation demodulating is proposed in this paper.Firstly,the space division multiplexing technology is used to establish a lookup table that specifies a unique code word sequence that corresponds one-to-one with the fringe order.Then,the phase-shifting sinusoidal fringes are used as carrier frequency fringes to directly modulate the code word to the amplitude intensity to form a space division multiplexing composite phase-shifting fringes.When the group of composite phase-shifting fringes is projected onto the measured object,both the wrapped phase and the modulation can be simultaneously demodulated from the captured composite deformed patterns.Normalization of the modulation can effectively suppress the influence of uneven reflectivity and demodulate the four grayscale codewords that can locate the fringe order,achieving absolute phase extraction without the need for any additional coding patterns.In order to improve the robustness of multi-level grayscale codeword extraction,the image morphology processing operations are utilized to segment the grayscale of the modulation,and a half-cycle connected domain codeword correction method is also proposed.The experimental results validate the feasibility and effectiveness of the proposed method.
作者
王建
曹益平
李小舜
WANG Jian;CAO Yi-ping;LI Xiao-shun(College of Electronics and Information Engineering,Sichuan University,Chengdu 610065,China)
出处
《光学与光电技术》
2024年第2期16-27,共12页
Optics & Optoelectronic Technology
基金
国家自然科学基金(62375188)资助项目。
关键词
条纹投影轮廓术
调制度
绝对相位提取
连通域
条纹级次
fringe projection profilometry
modulation
absolute phase extraction
connected domain
fringe order
