• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.487-491
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• 2009

The inverse halftoning is processing to restore the image made binary to former step image. There are smoothing and gaussian filtering in the technique so far. However, there are still a lot of insufficient points in past inverse halftoning. The removal of the noise and the edge enhansment are closely related in inverse halftoning. It is difficult to do both the noise rednctiom and the edge enhansment in high accuracy at the same time in the technique so far. The technique that can achieve both the removal of the noise and the emphasis of Edge at the same time is expected as future tasks. Then, it was tried to apply the Kalmann filtering to inverse halftoning. In the actual experiment, the effectiveness of the application of the Kalmann filtering to inverse halftoning comparing it with the technique so far was shown.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.123-131
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• 2005

Among the digital halftoning, the error diffusion halftoning gives better subjective quality than other halftoning techniques. But it also makes edges of objects blurred. To overcome the defect, this paper proposes the modified error diffusion halftoning algorithm to enhance the edges using the spatial perceptual properties of the human visual system. Using the properties that the human eyes perceive not the pixel's luminance itself but the local average luminance and the information that human eyes perceive spatial variation, the proposed method computes information of edge enhancement(IEE). The IEE is added to the quantizer's input pixel and feeds into the halftoning quantizer. The quantizer produces the halftone image having the enhanced edge. Also this paper proposes the technique that the coefficients of the error diffusion filter are adapted according to the correlation among color components. The computer simulation results show that the proposed method produces finer halftoning images than conventional methods due to the enhanced edges. And the proposed method also preserves similar in edges to original image and reduces some defects such as color impulse and false contours.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.984-990
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• 2009

Halftoning is very important image processing techniques in the digital printing industry which is a process of converting a continuous-tone image to bi-level tone image. In this paper we introduce a new digital halftoning method based on maze generation algorithm as a replacement algorithm of halftoning with space-filling curve. Previous error-diffusion methods based on space-filling curve suffer from regular pattern artifacts from uniform scan pattern. We use maze generation algorithm to remove this undesirable pattern of space-filling curve method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.516-519
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• 2009

In the printer and the facsimile communication, digital halftoning is extremely important technologies. Error diffusion method is applied easy for color image halftoning. But the problem in error diffusion method is that a quite unrelated color has been generated though it is necessary to express the area of the grayscale in the black and white when the image that there is an area of the grayscale on a part of the color image is processed. The halftoning was assumed to be a combinational optimization problem to solve this problem, and the method of using SA (Simulated Annealing) was proposed. However, new problem existed because the processing time was a great amount compared with error diffusion method. Then, we propose the new error diffusion method.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.684-688
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• 2009

In this paper, it proposes the technique to restore from a binary image in the color image. The color image is composed of three element images of red, green and blue. Therefore, the color image is first divided into a red, green, and blue element, and the Inverse Halftoning[2]$\sim$[4] is processed to each element images. Finally, each element images is collectively displayed. In that case, the Kalman filter was applied to the Inverse Halftoning for the restoration accuracy improvement of the image. As a result, it was possible to restore it in the color image as well as the time of a monochrome image. Moreover, the result that the restoration accuracy had improved even when which combining with the technique by using the Kalman filter for the Inverse Halftoning so far came out.

• Journal of Digital Convergence
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• v.12 no.1
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• pp.415-421
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• 2014

In this paper, we proposed problem and improvement of halftoning using random space filling curve. Random space filling curve is developed as a solution for shortcoming which space filling curve has self-similarity. It is used to reduce regular pattern can be occurred in constant brightness area in order that randomness apply to scanning path. But there is a problem that some area along scanning path can show too bright result in halftoning using random space filling curve. In this paper, we analyzed cause of problem and proposed single pixel error diffusion as a solution method. This method can avoid over-accumulated error and show better result in halftoning.

• Journal of Korea Multimedia Society
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• v.2 no.3
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• pp.308-319
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• 1999

In this paper we propose a new color inverse halftoning for color prints halftoned by clustered-dot. The proposed method divide channel image into blocks and then extract moire region according to its strength. To get more natural continuous tone image in human vision, the proposed method smooths the extracted moire region in proportion to moire strength. It can also preserve the significant edges well by considering edge information of color halftone image in the process of inverse halftoning. Experimental results show that the proposed method can make more improved inverse halftoning. Experimental results show that the proposed method can make more improved inverse halftoning image than the results of previous works. It could be applied to field of multimedia application, such as digital library construction, color print image compression and multimedia authoring.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.79-85
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• 2013

In this paper, we discussed the traditional methods of generating digital halftoning image and DCT transform. Then we propose a new and simple halftoning algorithm that is based on DCT transformation. We do the feasibility test to verify the proposed algorithm. So we assessed several images generated by adjusting weights of DCT coefficients. As a result, we got the better result for weights of the ramp function type than for weights of the step function type through experiment. As a simple application, we can apply our algorithm to the MPEG video for generating the halftoning video.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.11
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• pp.1464-1472
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• 1995

In this paper, we propose an error diffusion image halftoning technique based on the noise spectrum shaping. The new technique can arbitrarily control the shape of the display error spectrum whereas conventional halftoning algorithms have been known to minimize dc errors only in which case edge information cannot be properly rendered. As a method for estimating the error diffusion coefficients, a least mean square (LMS) approach is adopted.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.12a
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• pp.81-84
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• 2000

Digital Halftoning convert a continuous-tone images to a binary images. Inverse halftoning addresses the problem of recovering a continuous image from a halftoned binary image. Simple low pass filtering can remove the high frequency noise but it also removes the edge information. Thus the edge information should be separated from the halftoning noise. As a result, the edge of result image is blurring. This paper present that we obtain continuous-tone-image which using Anisotropic diffusion filter. To reduce noise without blurring the edges of reconstructed image use edge map. The experimental results show that proposed method gives a higher PSNR and better subjective quality than conventional methods. As a result, the edge information of reconstructed image reduce blurring.