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Standard test image

About: Standard test image is a research topic. Over the lifetime, 5217 publications have been published within this topic receiving 98486 citations.


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Proceedings Article
01 Jan 2004
TL;DR: The creation and application of a new digital color test target useful for research and development of color imaging systems that has several advantages over previous types of targets that include spatial resolution, dynamic range, spectral resolution, metameric properties, lack of noise, and continuous tonal variations.
Abstract: Standard, easily accessible, test targets have long served the field of color imaging as a foundation for comparison of the performance of various imaging systems and algorithms and the open and meaningful exchange of research results. This paper details the creation and application of a new digital color test target useful for research and development of color imaging systems. The target has several advantages over previous types of targets that include spatial resolution, dynamic range, spectral resolution, metameric properties, lack of noise, and continuous tonal variations. All these features can be important for visual assessment, computational analysis, and colorimetric evaluation. This target, known as METACOW, is freely available to all performing research in color imaging. Introduction and Objectives Test targets of various sorts have been tremendously helpful in color imaging research and development. Perhaps the most widely used and recognized instantiation is the GretagMacbeth ColorChecker color rendition chart originally designed by McCamy et al.1 approximately 30 years ago. The ColorChecker was designed with an array of 24 color patches that could be easily evaluated visually and instrumentally. The design was such that the spectral reflectance characteristics of the chart, not just the colors, were created to simulate objects of special interest such as blue flowers (notoriously difficult to reproduce with photographic color film), skin tones, and a nonselective gray scale. The ColorChecker has been so widely used, and was so effectively designed, that its 24 color patches can often be considered as memory colors to scientists and engineers in color imaging. More recent evolution of digital photographic systems have prompted the evolution of the ColorChecker to a new second form embodied as the GretagMacbeth ColorChecker DC color reference chart.2 The ColorChecker DC serves similar purposes, but with an order of magnitude more patches (237 instead of 24) it was designed with some of the opensystems properties of digital color imaging in mind. It includes replicate gray scales around the chart to evaluate the spatial uniformity of color balance and tone reproduction. The large number of patches and extended gamut facilitate use of the ColorChecker DC in construction of ICC profiles for scanner or camera characterization. And while reproduction of the ColorChecker DC can be evaluated both visually and instrumentally, visual evaluation is far more difficult with such a large number of color patches. It is safe to assume that the 237 patches of the ColorChecker DC will never become widely recognized memory colors and that the usefulness of the target in psychophysical experiments is somewhat limited. Similar applications are served by test targets such as the well-known ANSI IT8 targets3,4 that consist of large numbers of well-characterized color patches that can be used for scanner characterization and related applications. Again, such targets are of limited practical use in psychophysical evaluation of imaging systems due the large number of patches although some versions have a small area of pictorial content more amenable to human judgement. For visual evaluation of imaging systems or imaging algorithms, standard (actual or de facto) pictorial images are often used by various investigators to allow comparison of research results and combination of data from various studies. Well-known examples include the SCID, standard color image data, and SHIPP, standard high precision picture data, images that are available in digital form in various color representations.5-7 Previous examples provide targets that well represent two categories of need. The first are well defined spectrally and instrumentally but often with too many patches for easy visual evaluation. The second are standard digital images that are well defined colorimetrically and appropriate for visual evaluation, but difficult to assess instrumentally. They are also potentially impacted by the original image capture technology. The objective of the test target described in this paper is two bridge the gap between those two categories and produce an image that can be used in research and development that is both well specified spectrally and contains continuously shaded areas that are useful for perceptual judgements. This image is not intended to replace both of the previous categories, but rather to supplement them with a new type of test image with significant practical utility. Additional objectives in the development of this target include eliminating noise in the target itself, including metameric reflectance pairs, and being of sufficient spatial and photometric resolution to be applicable to the evaluation of essentially any imaging technology. The addition of metameric reflectance pairs alone is a significant advance in practical utility over previous color charts.

21 citations

Patent
08 Dec 2005
TL;DR: An image capture device for capturing a color image, comprising an image sensor comprised of discrete light sensitive picture elements overlaid with a color filter array (CFA) pattern to produce sensor color image data corresponding to the CFA pattern, is described in this article.
Abstract: An electronic image capture device for capturing a color image, comprising an image sensor comprised of discrete light sensitive picture elements overlaid with a color filter array (CFA) pattern to produce sensor color image data corresponding to the CFA pattern; an A/D converter for producing uninterpolated digital CFA image data from the sensor color image data; a processor for processing the uninterpolated digital CFA image data to produce interpolated image data and for forming a TIFF image file containing both the uninterpolated CFA image data and the interpolated image data; and a memory for storing the TIFF image file.

21 citations

Patent
13 Oct 2004
TL;DR: In this article, a document camera has an image processing apparatus, which acquires the contour of an image of an original by means of a Roberts filter, and determines the projection parameters showing the relationship between the image of the original and the shape of the actual original from the positions of the corners of the quadrangle.
Abstract: A document camera has an image processing apparatus, which acquires the contour of an image of an original by means of a Roberts filter. The image processing apparatus detects straight lines as candidates for forming an image of the original from the acquired contour and acquires the shape of a quadrangle of the original. The image processing apparatus determines the projection parameters showing the relationship between the shape of the image of the original and the shape of the actual original from the positions of the corners of the quadrangle and executes an operation of projection/transformation on the image of the original. The document camera outputs the image data of the image to a projector, which projects an image of the original on a screen according to the image data.

21 citations

Journal ArticleDOI
TL;DR: The results of the study show that NCD can be used to address some of the selected image comparison problems, but care must be taken on the compressor and image format selected.
Abstract: Similarity metrics are widely used in computer graphics. In this paper, we will concentrate on a new, algorithmic complexity-based metric called Normalized Compression Distance. It is a universal distance used to compare strings. This measure has also been used in computer graphics for image registration or viewpoint selection. However, there is no previous study on how the measure should be used: which compressor and image format are the most suitable. This paper presents a practical study of the Normalized Compression Distance (NCD) applied to color images. The questions we try to answer are: Is NCD a suitable metric for image comparison? How robust is it to rotation, translation, and scaling? Which are the most adequate image formats and compression algorithms? The results of our study show that NCD can be used to address some of the selected image comparison problems, but care must be taken on the compressor and image format selected.

21 citations

Patent
Bum-Suk Lee1, Eung-Sang Lee1, Gi-Chang Park1, Jong-Jin Kim1, Park Chan Youn1 
22 Dec 2010
TL;DR: A display panel test apparatus includes an image pickup part which picks up an image from a target display panel; a jig including a receiving part which receives the target display panels, a fixing part which fixes the image pickup parts, and an adjusting part which adjusts an image pickup angle of the pickup part; a pattern generating part which provides the display panel with a test pattern; a defect extracting part which analyzes test image data provided from the image pick up part using a defect extractor and extracts display defect information, where the defect extracting algorithm includes different settings corresponding to different types
Abstract: A display panel test apparatus includes: an image pickup part which picks up an image from a target display panel; a jig including a receiving part which receives the target display panel, a fixing part which fixes the image pickup part, and an adjusting part which adjusts an image pickup angle of the image pickup part; a pattern generating part which provides the target display panel with a test pattern; a defect extracting part which analyzes test image data provided from the image pickup part using a defect extracting algorithm and extracts display defect information, where the defect extracting algorithm includes different settings corresponding to different types of display defects; and a control part which generates evaluated data corresponding to a viewing angle of the target display panel using the image pickup angle of the image pickup part and the display defect information.

21 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20231
20228
2021130
2020232
2019321
2018293