• Proceedings of the Korea Information Processing Society Conference
• /
• 2010.11a
• /
• pp.1118-1121
• /
• 2010

With the advent of cell phone digital cameras, and sophisticated photo editing software, digital images can be easily manipulated and altered. Although good forgeries may leave no visual clues of having been tampered with, they may, nevertheless, alter the underlying statistics of an image. Most digital camera equipped in cell phones employ a single image sensor in conjunction with a color filter array (CFA), and then interpolates the missing color samples to obtain a three channel color image. This interpolation introduces specific correlations which are likely to be destroyed when tampering with an image. We quantify the specific correlations introduced by CFA interpolation, and describe how these correlations, or lack thereof, can be automatically detected in any portion of an image. We show the efficacy of this approach in revealing traces of digital tampering in lossless and lossy compressed color images interpolated with several different CFA algorithms in test cell phones.

• ETRI Journal
• /
• v.44 no.1
• /
• pp.94-104
• /
• 2022

Because of its convenience and compatibility with various image processing techniques, digital image representation of holograms is generally used in digital holography, and thus, quality assessment of digital holograms is an essential issue. This study proposes a new objective quality metric for digital phase hologram image processing. The proposed metric is based on a newly defined phase distortion created by taking the 2π periodicity of phase information into account. The experimental results show that the proposed metric correlates with reconstruction image quality better than the existing metric under random distortions and also works well with JPEG 2000 compression. It is expected to be broadly used in phase image processing and compression applications including phase holograms.

• 전자공학회논문지 IE
• /
• v.48 no.1
• /
• pp.51-56
• /
• 2011

In this paper, a variety of digital image processing technique was applied to improve the quality of medical images which is a chest CR image. And the image quality was performed. On the other hand, the high-frequency emphasis filtering and the histogram equalization were realized by MATLAB programs to better the contrast of the chest CR image. As a result of simulation, the sharpness of the original image was elevated by the high-frequency emphasis filtering and the histogram equalization. To evaluate the degree which is improved the image quality by the digital image processing, the subjective evaluation is used by the observation of the image. The sensitivity which is the probability to find a signal or a lesion is calculated. The sensitivity of the image performed the high-frequency emphasis filtering and the histogram equalization became more improved than that of the original and the digital image processing performed in the medical image improved the quality of the image.

• Journal of the Korea Convergence Society
• /
• v.9 no.7
• /
• pp.185-191
• /
• 2018

The digital technologies brought a structural transformation to cinema, have lead a change in the way of existence of an assembly of images called cinema, and have shared expression methods with new-media. To look into how in terms of cinema style of the film era and the digital era are different, this article will focus on the matter of 'indexicality.' From the point of view of perceptive realism the discourses on digital image deconstruct the dichotomy between illusionism and classical realism. Therefore the actuality of an image does not depend on only indexicality but has much to do with how the viewers fundamentally perceive the image. In this age of digital cinema it does not matter to distinct a composite-image from a reality-image. This article inquires the relation of indexicality, the world and digital images in digital cinema on the level of reception, and reconsider in terms of image production.

• Journal of the Korean Geotechnical Society
• /
• v.38 no.5
• /
• pp.61-71
• /
• 2022

Soil color is used to determine soil classification and its physical, chemical, and biological properties. Visual determination is the most commonly used method for identifying soil color. However, it is subjective and, in many cases, non-repeatable. Digital image processing obtains useful information from digital images, accelerates soil classification, and enables the rapid identification of soil types in a field. This study develops a digital image processing-based soil color analysis technology that can consider irregular light conditions in the field. The digital image studio was designed to simulate the characteristics of natural light (illuminance and color temperature). Also, digital images of two soil samples (Jumoonjin sand and Anseong weathered soil) were captured under 12 different light conditions. For the RGB and CIELAB color systems, soil color intensities of 24 images were obtained using digital image processing. CIELAB was suitable for dealing with irregular light conditions in the field.

• The Journal of the Korea Contents Association
• /
• v.6 no.4
• /
• pp.89-97
• /
• 2006

Such changes that the digital paradigm brought propels a change of the value system itself in the existing society so that a way of thinking that differentiates oneself from others is getting much stronger. As public interests are higher in the image production on the internet, such authoring environments as development of related technologies, expansibility of information, and systematization of available information continue to change. Therefore, a variety of unique image presentations that fit to the changed environments are necessary and an expression method is indispensable for such image production. This study focuses on digital image creating in which a synectics method is applied. It suggests digital image application methods and examples that contain not just simple image distortion or variation but intrinsic significance. It is believed that it will be of good use to produce a variety of unique and innate digital images in the end.

• Proceedings of the Optical Society of Korea Conference
• /
• 1999.08a
• /
• pp.160-161
• /
• 1999

• Journal of Korea Multimedia Society
• /
• v.16 no.12
• /
• pp.1475-1481
• /
• 2013

A subject always follows desire caused by primal lack which exceeds its desire on survival. At this time, the immediacy provided by vision and the excellence of information become important means in mediating the object of the desire. The subject who is attracted to the vision and image toward desire cannot get out of the trap of the image. When the film raised unconsciousness to pleasure while reproducing the desire of 'mirror image', the digital image presents a virtual experience on the desire of subject by dominating audience with its perfect image regardless of the existence of the object. This study attempted to prove that unconsciousness of subject has close relation with digital image, which takes other's desire as its own by wrongly identifying other's desire as its own desire and captivates subject by the experience of desiring. According to the result of study, digital image escalates the imaginary desire of subject through the virtuality of image close to reality and captivates subject by giving pleasure to the unconsciousness of subject as a path in going along with the desire of other.

• Korean Journal of Digital Imaging in Medicine
• /
• v.10 no.2
• /
• pp.23-31
• /
• 2008

Computed radiography(CR) has been widely used in the field of diagnostic radiography since digital X-ray image was introduced. The imaging performance of CR system was studied by analyzing the digital image data of the CR images which are the outcomes of the whole imaging system composed of image plate(IP), laser digitizer, analoge-digital convertor, and a given image processing unit. In this study, we used a conventional CR system made by Agfa. From the flat field image of 150$\times$150 image pixels, signal-to-noise ratio(SNR) was calculated. SNR of the CR image increases in proportion to logarithm value of the X-ray exposure irradiated on the IP. SNR is less than about 6 at the exposure below 0.2mR and is more than 10 at the exposure above 0.54mR. In our study, most of images obtained by the smaller exposures less than 2.0mR can not be readable. In general, the minimum value of the SNR ranges from 3 to 5. We obtained modulation transfer function(MTF) by analyzing the bar pattern image which was made under conditions as follows: X-ray tube potential was 55kVp, the IP exposure was 0.54 mR, and the distance between X-ray source to IP was 2m, where bar pattern was located on the IP. MTF is 23% at 2.5lp/mm spatial frequency. Provided that the MTF of noise equivalent modulation is 10%, the CR system has the limiting spatial resolution of 3.2lp/mm. If the image sharpness is evaluated by the spatial frequency where MTF is 50%. the corresponding spatial frequency is 0.5$\sim$0.75lp/mm. MTFA(Modulation Transfer Function Area) is 1.0lp/mm. Compared with the Fuji CR whose MTFA is 1.1lp/mm, Agfa CR in this study shows almost same MTFA performance.

• ETRI Journal
• /
• v.34 no.1
• /
• pp.138-141
• /
• 2012

This letter proposes a real-time digital image stabilization system for cell phone cameras without the need for frame memory. The system post-processes an image captured with a safe shutter speed using an adaptive denoising filter and a global color correction algorithm. This system can transfer the normal brightness of an image previewed under long exposure to the captured image making it bright and crisp with low noise. It is even possible to take photos in low-light conditions. By not needing frame memory, the approach is feasible for integration into the size-constrained image sensors of cell phone cameras.