Optical distance control for a multi focus image in camera phone module assembly

Kim, H.T.; Kang, Sungbok; Kang, Hyun-Su; Cho, Y.J.; Park, N.G.; Kim, J.O.

doi:10.1007/s12541-011-0107-7

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…Proper lubrication affects the coefficient of friction and thus the die load. [10,11] It has been revealed in the previous works that a deteriorating die performs poorly and thus product quality is compromised. A low die load during the forging operation improves die life.…”

Section: Define (Hot Closed Die Forging)mentioning

confidence: 99%

Parametric optimization of hot forging process: a six sigma based approach

Satyam¹,

Srivastava²,

Kumar³

et al. 2021

E3S Web Conf.

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One of the major concerns for industries in the modern world is to focus efforts on producing high quality products with minimal costs. Various quality improvement philosophies have emerged in recent times, Six Sigma being one of the most practical and efficient techniques for quality improvement of processes. In this work, Six Sigma based DMAIC (Define, Measure, Analyze, Improve, Control) approach is used to enhance productivity and quality performance, and to make the hot forging process robust to quality variations. Finite element method has been employed for the simulation of hot forging of the connecting rod. The influence of design and process parameters is investigated for the response ‘forging die load’. Analysis of various critical parameters and the interaction among them has been carried out with the help of Taguchi’s method of experimental design. To further optimize the response and make the analysis more precise and robust, response surface methodology has been incorporated. Parameters have been optimized, leading to the accomplishment of a minimized forging die load which is verified using a confirmation experiment. Confirmatory results reveal the potential of the DMAIC approach of Six Sigma in optimizing the process parameters successfully and thereby present significant applicability in the industry.

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Section: Define (Hot Closed Die Forging)mentioning

confidence: 99%

Parametric optimization of hot forging process: a six sigma based approach

Satyam¹,

Srivastava²,

Kumar³

et al. 2021

E3S Web Conf.

View full text Add to dashboard Cite

show abstract

“…Because distinguishing the defect between the intensity of the defect itself and the background is difficult, an image-processing algorithm that uses multiple Laplacian of Gaussian masks were implemented to detect the defects of the micro lens. Moreover, a dynamic focus region from several narrow region of interests across the vision screen was used to increase the sharpness and determine the focal distance and focal point for better image acquisition [10]. Various computation methods that use the gray-level difference, Tenengrad measurement, correlation evaluation, statistical approaches, Fourier transform, wavelet, and edge-based measurement have helped to reduce the processing time and increase the sharpness [10].…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, a dynamic focus region from several narrow region of interests across the vision screen was used to increase the sharpness and determine the focal distance and focal point for better image acquisition [10]. Various computation methods that use the gray-level difference, Tenengrad measurement, correlation evaluation, statistical approaches, Fourier transform, wavelet, and edge-based measurement have helped to reduce the processing time and increase the sharpness [10]. The computation methods could be obtained from a flat surface at a single focal distance.…”

Section: Introductionmentioning

confidence: 99%

Optical Design of a Novel Collimator System with a Variable Virtual-Object Distance for an Inspection Instrument of Mobile Phone Camera Optics

2021

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The resolution performance of mobile phone camera optics was previously checked only near an infinite point. However, near-field performance is required because of reduced camera pixel sizes. Traditional optics are measured using a resolution chart located at a hyperfocal distance, which can only measure the resolution at a specific distance but not at close distances. We designed a new collimator system that can change the virtual image of the resolution chart from infinity to a short distance. Hence, some lenses inside the collimator systems must be moved. Currently, if the focusing lens is moved, chromatic aberration and field curvature occur. Additional lenses are required to correct this problem. However, the added lens must not change the characteristics of the proposed collimator. Therefore, an equivalent-lens conversion method was designed to maintain the first-order and Seidel aberrations. The collimator system proposed in this study does not move or change the resolution chart.

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“…Auto light is observed less often in industrial vision systems, but the principle is similar to that of auto focusing. [4,5] The study showed that automatic illumination can be achieved by light variation instead of optics variation in auto focusing. Common light control is based on a single light, but the best light for a specific target can differ.…”

Section: Introductionmentioning

confidence: 99%

Mixing and Simplex Search for Optimal Illumination in Machine Vision

Kim

Cho

Jin

et al. 2014

International Journal of Optomechatronics

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Mixed-color illumination affects the quality of images in industrial vision system and it is important to optimize color and intensity for image acquisition. This study used simplex search to find the optimal illumination in a short amount of time. A typical color mixer synthesized various color of lights by changing the inputs of RGB power LEDs and passing the lights through an optical system. The image quality under mixed-color illumination was calculated according to the sharpness. For the purpose of optimal illumination using simplex search, a probe network was organized with N þ 1probing points for N inputs. The shape of the probe network, simplex, was varied through procedures of extension, contraction, and shrinkage. The inputs of the color mixer were changed until the size of the simplex became smaller than a threshold. The simplex search was tested for commercial semiconductor patterns, and was useful for finding the optimal illumination.

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Optical distance control for a multi focus image in camera phone module assembly

Cited by 12 publications

References 21 publications

Parametric optimization of hot forging process: a six sigma based approach

Parametric optimization of hot forging process: a six sigma based approach

Optical Design of a Novel Collimator System with a Variable Virtual-Object Distance for an Inspection Instrument of Mobile Phone Camera Optics

Mixing and Simplex Search for Optimal Illumination in Machine Vision

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