摘要:
Embodiments of the present invention are directed to determining the spectral vector of electromagnetic radiation reflected from, transmitted through, or emitted from a sample using a set of n intensity measurements. In general, the spectral vector has a dimension k that is greater than the number of measured intensities n. However, in many cases, the physical and chemical constraints of a system, when properly identified and modeled, effectively reduce the number of unknowns, generally the k components of the spectral vector, to an extent that allows for the spectral vector to be characterized from a relatively small number n of measured intensities.
摘要:
In one aspect, an image is quantized by assigning sub-ranges of pixel values in the image to respective quantization levels. The quantized image is encoded based at least in part on a mask lookup table assigning index values to respective masks, wherein each mask corresponds to a respective spatial distribution of the quantization levels. In another aspect, a code corresponding to an encoded image with pixel values quantized to respective quantization levels is received. The code is decoded based at least in part on a mask lookup table assigning index values to respective masks, wherein each mask corresponds to a respective spatial distribution of the quantization levels.
摘要:
In one aspect, an image is quantized by assigning sub-ranges of pixel values in the image to respective quantization levels. The quantized image is encoded based at least in part on a mask lookup table assigning index values to respective masks, wherein each mask corresponds to a respective spatial distribution of the quantization levels. In another aspect, a code corresponding to an encoded image with pixel values quantized to respective quantization levels is received. The code is decoded based at least in part on a mask lookup table assigning index values to respective masks, wherein each mask corresponds to a respective spatial distribution of the quantization levels.
摘要:
A system and a method solve the estimation problem of finding reflectance R and illumination L. The system and method to solve a functional of the unknown illumination L such that a minimum of the functional is assumed to yield a good estimate of the illumination L. Having a good estimate of the illumination L implies a good estimate of the reflectance R. The functional uses a variational framework to express requirements for the optimal solution. The requirements include: 1) that the illumination L is spatially smooth; 2) that the reflectance values are in the interval [0,1] —thus, when decomposing the image S, the solution should satisfy the constraint L>S; 3) that among all possible solutions, the estimate of the illumination L should be as close as possible to the image S, so that the contrast of the obtained R is maximal; and 4) that the reflectance R complies with typical natural image behavior (e.g., the reflectance is piece-wise smooth).
摘要:
A method for enhancing an input image to produce an enhanced output image is provided. The method includes constructing a photographic-mask intermediate image without low-contrast details and a temporary-image intermediate image with enhanced mid-contrast details, retained high-contrast details, and reduced low-contrast details, and employing values for the photographic-mask intermediate image and temporary-image intermediate image to produce the enhanced output image that is globally and locally contrast-enhanced, sharpened, and denoised.
摘要:
Various embodiments of the present invention are directed to methods and systems for image processing that are unified in nature, carrying out many image-enhancement tasks together in a unified approach, rather than sequentially executing separately implemented, discrete image-enhancement tasks. In addition, the methods and systems of the present invention can apply image-enhancement to local, spatial regions of an image, rather than relying on global application of enhancement techniques that result in production of artifacts and distortions. In certain embodiments of the present invention, various different types of intermediate images are produced at each of a number of different scales from a received, input image. From these intermediate images, a photographic mask and temporary image are obtained, and the photographic mask and temporary image are then employed, along with a look-up table or function that receives values from the photographic mask and temporary image, to compute an enhanced, output image. In a described embodiment of the present invention, the intermediate images include low-pass, band-pass, photographic-mask, and temporary-image intermediate images computed at each of a number of different scales.
摘要:
Demosaicing convolution kernels are incorporated into the framework of bilateral filtering in order to reduce artifacts at abrupt intensity transitions when a color mosaic pattern is converted to an output image. As a consequence of the bilateral filtering within a window that is selected without intensity considerations, intensity values of pixels that are physically close are given greater weight than intensity values of more distant pixels and, simultaneously, intensity values that are quantitatively similar (i.e., photometrically similar) are given greater weight than intensity values that are quantitatively dissimilar. Using photometric similarity in a demosaicing operation reduces the effects of pixels on one side of an abrupt intensity transition in determining interpolated intensity values for pixels on the opposite side of the abrupt intensity transition.
摘要:
A method for enhancing an input image to produce an enhanced output image is provided. The method includes constructing a photographic-mask intermediate image without low-contrast details and a temporary-image intermediate image with enhanced mid-contrast details, retained high-contrast details, and reduced low-contrast details, and employing values for the photographic-mask intermediate image and temporary-image intermediate image to produce the enhanced output image that is globally and locally contrast-enhanced, sharpened, and denoised.
摘要:
A robust recursive operator for fast implementation of the computationally intensive module of Retinex-type image enhancement algorithms. The proposed module includes a cascaded recursive filter. The parameters of the filter are a function of the input signal, and are scale independent. Furthermore, the image is first processed according to an open and close prefilter, followed by application of the cascaded recursive filters. After application of the cascaded recursive filters, a post filter maximum output is applied to the signal. The module will usually be used as a part of a Retinex-type image processing system, which might use it after some preprocessing of an input image, and which will result in a manipulation of the input image and the module's output image.
摘要:
A system and a method for preventing counterfeiting activities utilize an image detection scheme that uses only a few portions of restricted-document images, i.e., templates, to determine whether an input image is a duplicate of a restricted-document image. The image detection scheme can reliably operate at very low resolutions, which allows the use of small kernels for image correlation and reduces the number of pixels that have to be actually processed. The system is designed to be incorporated into a host device, such as a copy machine, a scanner, a personal computer or a printer, to detect a potential counterfeiting activity, so that an appropriate action can be taken to prevent and/or to report the detected activity. The image detection scheme allows the system to operate at an increased detection speed, while minimizing the memory requirement. During an off-line training procedure, a training module of the system derives a parameter file that contains detection descriptors for the restricted-document images, including threshold intervals that are defined using selected kernels and templates of the restricted-document images. The type of kernels and templates selected by the training module can vary, depending on the desired memory requirement and the desired on-line performance. During an on-line detection procedure, a detection module of the system projects portions of the input image and compares the resulting projection value with the threshold intervals to derive template match candidates. The relative coordinates of the template match candidates in the input image are then compared with relative coordinates of the templates in the restricted-document images to determine if the input image matches a particular restricted-document image.