Review of Illumination and Skew Correction Techniques for Scanned Documents

Verma, Rajeev N.; Malik, Latesh

doi:10.1016/j.procs.2015.03.151

Cited by 15 publications

(7 citation statements)

References 8 publications

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“…Mathematical Problems in Engineering [30][31][32][33]. ose skew detection and correction algorithms are mainly aiming at detecting the deviation of the document orientation angle from the horizontal or vertical direction.…”

Section: Skew Correction Algorithmmentioning

confidence: 99%

An Improved Tool Wear Monitoring Method Using Local Image and Fractal Dimension of Workpiece

Yu¹,

Wang

Zhang³

et al. 2021

Mathematical Problems in Engineering

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Tool wear is a key factor that dominates the surface quality and distinctly influences the generated workpiece surface texture. In order to realize accurate evaluation of the tool wear from the generated workpiece surface after machining process, a new tool wear monitoring method is developed by fractal dimension of the acquired workpiece surface digital image. A self-made simple apparatus is employed to capture the local digital images around the region of interest. In addition, a skew correction method based on local fast Fourier transformation energy is also proposed for the surface texture direction adjustment. Furthermore, the tool wear quantitative evaluation was derived based on fractal dimension utilizing its high reliability for inherent irregularity description. The proposed tool wear monitoring method has verified its feasibility as well as its effectiveness in actual milling experiments using the material of AISI 1045 in a vertical machining center. Testing results demonstrate that the proposed method was capable of tool wear condition evaluation.

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Section: Skew Correction Algorithmmentioning

confidence: 99%

An Improved Tool Wear Monitoring Method Using Local Image and Fractal Dimension of Workpiece

Yu¹,

Wang

Zhang³

et al. 2021

Mathematical Problems in Engineering

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“…Hough transform, projection characteristics, Fourier transform and shearlet transform are algorithms commonly used for skew correction [14][15][16][17]. However, these algorithms are mainly proposed for detecting deviations of the document orientation angles from the horizontal direction or the vertical direction.…”

Section: Appl Sci 2018 8mentioning

confidence: 99%

Noncontact Surface Roughness Estimation Using 2D Complex Wavelet Enhanced ResNet for Intelligent Evaluation of Milled Metal Surface Quality

et al. 2018

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Machined surfaces are rough from a microscopic perspective no matter how finely they are finished. Surface roughness is an important factor to consider during production quality control. Using modern techniques, surface roughness measurements are beneficial for improving machining quality. With optical imaging of machined surfaces as input, a convolutional neural network (CNN) can be utilized as an effective way to characterize hierarchical features without prior knowledge. In this paper, a novel method based on CNN is proposed for making intelligent surface roughness identifications. The technical scheme incorporates there elements: texture skew correction, image filtering, and intelligent neural network learning. Firstly, a texture skew correction algorithm, based on an improved Sobel operator and Hough transform, is applied such that surface texture directions can be adjusted. Secondly, two-dimensional (2D) dual tree complex wavelet transform (DTCWT) is employed to retrieve surface topology information, which is more effective for feature classifications. In addition, residual network (ResNet) is utilized to ensure automatic recognition of the filtered texture features. The proposed method has verified its feasibility as well as its effectiveness in actual surface roughness estimation experiments using the material of spheroidal graphite cast iron 500-7 in an agricultural machinery manufacturing company. Testing results demonstrate the proposed method has achieved high-precision surface roughness estimation.

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“…Furthermore, project profile technique gave the best estimation for the angle when it comes to the accuracy, in opposite its time is the longest to be executed. In [7] an efficiency discussion of two techniques Principal Component analysis (PCA) and Hough transform is presented to overcome problems that spoils the scanned documents. In [8] projection profile method is proposed for skew detection for handwritten signature, they used horizontal projection for detecting the skew angle and correct it using rotation transformation.…”

Section: Related Workmentioning

confidence: 99%