T. G. Stockham, Jr. Image processing in the context of a visual model. Proc. IEEE, 60(7):828--842, July 1972.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....a mathematically ill posed problem. In order to alleviate this problem, additional assumptions on the unknowns are required. The most commonly used assumption is that the spatially smooth parts of S originate from the illumination image, whereas edges in S are due to the reflectance in the image. [13, 15, 8, 9, 14, 5, 22, 2, 7, 21, 18]. In a previous paper [10] a new variational based Retinex formulation to the Retinex problem was introduced. This formulation took into account the illumination smoothness assumption. In addition, it exploited the known limited range of the reflectance image, and the fact that this image, being ....

T. G. Stockham Jr, "Image Processing in the Context of a Visual Model" Proc. of the IEEE, Vol. 60, 828--842, 1972. 24 A The Retinex Algorithm for # # - Theory Let us look at the variational expression (Equation [2]), and assume that # #. If we ignore the inequality constraints, the optimal image l should satisfy

.... Varying Time independent Time dependent Tumblin Rushmeier 1993 [41] Upstill 1985 [43] Miller et al. 1984 [22] Cohen et al. 2001 [6] Tumblin et al. 1999 [40] Scheel et al. 2000 [33] Ward Larson et al. 1997 [18] Ward 1994 [45] Oppenheim et al. 1968 [26] Stockham 1993 [38] Chiu et al. 1993 [5] Schlick 1994 [34] Jobson et al. 1997 [15] Pattanaik et al. 1998 [27] Tumblin Turk 1999 [42] Ashikhmin 2002 [2] Fattal et al. 2002 [9] Reinhard et al. 2002 [31] Durand Dorsey 2002 [8] Ferwerda et al. 1996 [10] Durand Dorsey 2000[7] Pattanaik et al. 2000 ....

....content in an image tends to be high dynamic range, and high frequency content tends to be low dynamic range. By attenuating the low frequencies in the Fourier domain, HDR data may be compressed while the high frequencies (the low dynamic range detail) are preserved. Further work by Stockham [38] in 1972 tied the concept of homorphic filtering to properties of early portions of the HVS. He developed a visual model based on these properties and used it to define a measure of image quality. Chiu, Herf, Shirley, Swamy, Wang and Zimmerman s [5] investigation into global operators led them to ....

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T. Stockham. Image processing in the context of a visual model. In Proceedings of the IEEE, volume 60, pages 828--842, 1972.

....linear filtering is, whether one is aware of it or not, homomorphic filtering. Stockham advocated a kind of homomorphic filtering operation in which the logarithm of the input image was taken, followed by linear filtering (e.g. linear space invariant filters) followed by taking the antilogarithm [16]. In essence, what Stockham didn t appear to realize, is that such homomorphic filtering is already manifest in simply doing ordinary linear filtering on ordinary picture signals (whether from video, film, or otherwise) In particular, the compressor gives an image (ignoring noise and ) which has ....

T. G. Stockham, Jr., "Image processing in the context of a visual model," Proc. IEEE, vol. 60, pp. 828--842, July

....constant Q filters. If all that is desired is a single print, why not just try to formulate a super low contrast film or image sensor The superiority of the Wyckoff composite lies in the ability to control the process of going to the low contrast medium. For example, we might apply a homomorphic [8] filtering operation to 3 The dither did not have a perceivable effect on an 8 bit image, but when reducing a Wyckoff composite to 5 bits or less, the dither made a noticable improvement. the final composite, which would bring out improved details at high spatial frequencies, while reducing the ....

T. G. Stockham, Jr., "Image processing in the context of a visual model," Proc. IEEE, vol. 60, pp. 828--842, July 1972.

....and orientation. Later models incorporate more consideration of matching the experiments by vision scientists who used grating and contrast. In 1972, Stockham proposed a vision model for image processing, which is based on the nonlinear brightness adaptation mechanism of human vision [122]. Later additions on the HVS model that include transforming images into the frequency domain, color information, and orientation can be found in [47, 39, 88, 31] In literature, the most complete results involving the fields of image processing, image science, and vision science are two HVS ....

T. G. Stockham, Jr., "Image Processing in the Context of a Visual Model," Proceedings of the IEEE,Vol.60,No.7,July1972.

....of the transform, an addition of transforms will imply multiplication of the pictures. It might be argued that we do not perform any logarithmic resealing on the original image; however, many media for picture input, such as photographic film, do in fact exhibit logarithmic characteristics [19]. As the next transformation is done around a lower center frequency, r 2 , only a band around that frequency will be taken from the original image. This is indicated by the lower resolution grid imposed upon the original picture function for that frequency. The combined picture function d r1 ....

T. G. Stockham, Image processing in the context of a visual model, Proc. IEEE 60, 1972, 828842.

....the perceived images o m;n and t m;n is the same as that between the perceived t m;n and the underlying t m;n . Figure 7 differs from Figure 4 in two important ways. The first is that the contrasts between different luminace levels is considerably reduced. The second is the strong Mach bands [9, 10] which form on the boundaries beween adjacent regions with sharply different luminace levels. It is possible to see these bands in Figure 4 by holding the page between 11 and 12 inches from the face, or even closer to really exaggerate the effect. Acknowledgements We would like to thank Drs. ....

T.G. Stockham, Jr., "Image processing in the context of a visual model," Proceedings of the IEEE, 60 (1972) pp. 828-842.

....perceptually tuned coders transforms the images into the visual domain using a HVS model. The transformed images are then compressed using a lossy compression scheme that minimizes some quantitative distortion measure. During reconstruction the images are transformed back to the original domain [5]. Assuming the HVS model is accurate, it may be argued that the transformed image is what the eye sees. Therefore, by minimizing the quantitative distortion measure in the visual domain, one minimizes the perceptual distortions introduced by the coder. Another class of algorithms attempts to ....

T. Stockham Jr. "Image processing in the context of a visual model," Proc. IEEE, vol. 60, no. 7, pp. 828-842, July 1972.

....x k Gamma1 ) accomplishes the first two goals and occasionally correlates with the third. Unfortunately, distortion measures that have been found to be good measures of perceived quality in speech and images have often proved to be quite complicated and have usually lacked the first two properties[23, 24, 25, 26, 27, 28, 29]. As a result, the squared error distortion has dominated the literature with relatively rare extensions to other measures. For particular applications, one variation on the squared error distortion measure has provided a promising means of incorporating perceptually important characteristics of ....

T. G. Stockham, Jr. Image processing in the context of a visual model. In Proceedings of the IEEE, Volume 60, pp. 828-842, July 1972.

....a variety February 27, 1997 7 of visual models have been proposed for use in various image processing tasks. The simplest, arguably, include just a filter, for example the filter of (1) The next simplest, and perhaps most commonly cited in image processing, 31, p. 292] 28, p. 57] [32, 27], include also a memoryless nonlinearity, as shown in Fig. 2. Such nonlinearities account for Weber s law, which says that the smallest noticeable change in intensity is proportional to intensity. Most commonly it is represented as a logarithm or power law (e.g. intensity 1=3 ) More complex ....

T. J. Stockham, "Image processing in the context of a visual model," Proc. IEEE, vol. 60, pp. 828--842, July 1972.

....improvement. If all that is desired is a single print, why not just try to formulate a super low contrast film or image sensor The superiority of the Wyckoff composite lies in the ability to control the process of going to the low contrast medium. For example, we might apply a homomorphic [8] filtering operation to the final composite, which would bring out improved details at high spatial frequencies, while reducing the unimportant overall changes in density at low spatial frequencies. 7 Wyckoff analysis and synthesis filterbanks We can regard the Wyckoff film (or exposure ....

T. G. Stockham, Jr., "Image processing in the context of a visual model," Proc. IEEE, vol. 60, pp. 828--842, July 1972.

....The shadow detail may then be derived from the overexposed stream, the highlight detail from the underexposed stream, and the midtones from a combination of the two streams. The resulting extended response video may be displayed on a conventional HMD by using Stockham s homomorphic filter [T. G. Stockham, Jr. 1972] as the visual filter . The principle of extending dynamic range by combining differently exposed pictures is known as the Wyckoff principle [Mann and Picard, 1994a] in honor of Charles Wyckoff. Using a Wyckoff composite, I could be outside on bright sunny days and see shadow detail when I ....

T. G. Stockham, Jr. (1972). Image processing in the context of a visual model. Proc. IEEE, 60(7):828--842.

....The value for k is roughly 0:33. Most implementations of this aspect of visual sensitivity treat it as a point process using the value of a single pixel for the central square and the average of the surrounding pixels for the background. Various instantiations of the amplitude nonlinearity include [23, 24, 3, 25, 26]. 2.1.2 Contrast Sensitivity Function The human visual system s contrast sensitivity function (also called the modulation transfer function) provides a characterization of its frequency response. The contrast sensitivity function can be thought of as a bandpass filter. There have been several ....

T. J. Stockham, "Image processing in the context of a visual model," Proc. IEEE, vol. 60, pp. 828--842, July 1972.

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T. G. Stockham, Jr. Image processing in the context of a visual model. Proc. IEEE, 60(7):828--842, July 1972.

No context found.

T. G. Stockham, Jr., "Image processing in the context of a visual model," Proc. IEEE, vol. 60, no. 7, pp. 828--842, July 1972.

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Stockham Jr., T.G. 1972. Image processing in the context of a visual model. Proc. of the IEEE, 60:828--842.

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T. G. Stockham Jr, "Image Processing in the Context of a Visual Model" Proc. of the IEEE, Vol. 60, 828--842, 1972.

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Stockham, T.G., Image Processing in the Context of a Visual Model. Proc. IEEE, 1972. 60: p. 828 - 842.

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T. G. Stockham Jr, "Image Processing in the Context of a Visual Model" Proc. of the IEEE, Vol. 60, 828--842, 1972. 27 A The Retinex Algorithm for # # - Theory Let us look at the variational expression (Equation [2]), and assume that # #. If we ignore the inequality constraints, the optimal image l should satisfy

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T. G. Stockham Jr, "Image Processing in the Context of a Visual Model", Proc. of the IEEE, Vol. 60, 828--842, 1972. 25

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T.G. Stockham. Image Processing in the Context of a Visual Model, Proceedings of the IEEE, 60:828--842 2

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T. G. Stockham, "Image processing in the context of a visual model," Proceedings of the IEEE 60, pp. 828--841, 1972.

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Stockham, T. G. Jr. 1972. "Image Processing in the Context of a Visual Model," Proc. IEEE 60(7):828-842 (July).

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