Abstract:
A decoder receives for decoding and post-processing for display an HDR (high dynamic range) image comprising a first coded image (e.g., a JPEG-HDR baseline image) and a second coded image (e.g., a JPEG-HDR ratio image). The first coded image is partially decoded and post-processed according to a post-processing command (e.g., scaling) to output a first decoded and post-processed image. The second coded image is also partially decoded and post-processed according to the post-processing command to output a second decoded and post-processed image. The first and the second decoded and post-processed images are combined to output a decoded HDR image according to the post-processing command.
Abstract:
Techniques are provided to encode and decode image data comprising a tone mapped (TM) image with HDR reconstruction data in the form of luminance ratios and color residual values. In an example embodiment, luminance ratio values and residual values in color channels of a color space are generated on an individual pixel basis based on a high dynamic range (HDR) image and a derivative tone-mapped (TM) image that comprises one or more color alterations that would not be recoverable from the TM image with a luminance ratio image. The TM image with HDR reconstruction data derived from the luminance ratio values and the color-channel residual values may be outputted in an image file to a downstream device, for example, for decoding, rendering, and/or storing. The image file may be decoded to generate a restored HDR image free of the color alterations.
Abstract:
The invention relates to techniques for light leakage compensation in a multi-channel display device. The invention may be particularly useful in calculating single-channel emission spectra for liquid crystal displays (LCD). In order to accurately model and calibrate a display device, an accurate spectral output estimate for each of the individual color channels is needed. The invention provides techniques to compensate for light leakage from adjacent color channels that cause hue shifts in the images reconstructed by the display device. In accordance with the invention, a light leakage emission spectrum can be determined for each color channel of a display based on a measured emission spectrum for the display at a minimum level and assumed emission spectra for light sources in the display. A single-channel emission spectrum is the difference between a cumulative color channel emission spectrum measurement and the light leakage spectra of adjacent color channels.
Abstract:
In general, the invention relates to techniques for reconstructing color channels in a multi-channel display device. The invention may be particularly useful in reconstructing the light source spectra for the color channels of liquid crystal displays (LCD). In order to accurately model and calibrate a display device, an accurate light source spectrum estimate for each of the individual color channels is needed. In accordance with the invention, a light source spectrum can be determined for each color channel of a display based on measured emission spectra for the color channels, an inverted contrast ratio for the display, and an assumed transmission spectrum for a light valve in the display. The invention provides techniques to compensate for light leakage from adjacent color channels with regards to wavelength dependent transmissions that cause hue shifts in images reconstructed by the display device.
Abstract:
A method of generating a color characterization model for an input imaging device includes capturing a target having plural patches using the input imaging device to produce plural digital values in a device-dependent color space, the plural digital values having corresponding target measurements in a color characterization set. The method further includes determining if any of the plural digital values are collinear with each other, and removing, in a case where it is determined that digital values are collinear with each other, at least one of the collinear digital values and corresponding target measurements from the color characterization data set. In addition, the method includes generating the color characterization model for the input imaging device based on the plural digital values and corresponding target measurements remaining in the color characterization set. An apparatus for generating a color characterization model for an input imaging device is also provided.
Abstract:
A decoder receives for decoding and post-processing for display an HDR (high dynamic range) image comprising a first coded image (e.g., a JPEG-HDR baseline image) and a second coded image (e.g., a JPEG-HDR ratio image). The first coded image is partially decoded and post-processed according to a post-processing command (e.g., scaling) to output a first decoded and post-processed image. The second coded image is also partially decoded and post-processed according to the post-processing command to output a second decoded and post-processed image. The first and the second decoded and post-processed images are combined to output a decoded HDR image according to the post-processing command.
Abstract:
One embodiment of a method for finding an aim position of a measuring device may include building a color model for an imaging device, initializing a color encoding image, displaying or printing the image on the imaging device, acquiring measurement with the measuring device, converting the measurement into imaging device code values using the color model, calculating said aim position from said device code values. The color encoding image sets one-to-one relationship between coordinates and colors. The image is output on the imaging device and measured by the measuring device. The measurement is converted using the color model to the device code values. The aim position then calculated from position of the device code values in the encoding image.
Abstract:
Techniques are provided to encode and decode image data comprising a tone mapped (TM) image with HDR reconstruction data in the form of luminance ratios and color residual values. In an example embodiment, luminance ratio values and residual values in color channels of a color space are generated on an individual pixel basis based on a high dynamic range (HDR) image and a derivative tone-mapped (TM) image that comprises one or more color alterations that would not be recoverable from the TM image with a luminance ratio image. The TM image with HDR reconstruction data derived from the luminance ratio values and the color-channel residual values may be outputted in an image file to a downstream device, for example, for decoding, rendering, and/or storing. The image file may be decoded to generate a restored HDR image free of the color alterations.
Abstract:
The invention is directed to generic spectral modeling techniques applicable to a variety of imaging devices. A generic spectral model may include a general channel model capable of modeling spectral characteristics of imaging devices and a look-up table (LUT) capable of compensating for cross-channel interaction and possibly other characteristics that are difficult to model, such as non-linear characteristics of imaging devices. In this way, the generic spectral model includes aspects of both a conventional physical model and a conventional brute force model. Digital values, i.e., pixel counts, of each channel of an imaging device are adjusted by the LUT of the generic spectral model to include cross-channel interaction. The channel model then accurately predicts spectral emissions for each channel of the imaging device based on the adjusted digital values. The generic spectral model converts the predicted spectral emissions to a device-independent color space.
Abstract:
Techniques are provided to encode and decode image data comprising a tone mapped (TM) image with HDR reconstruction data in the form of luminance ratios and color residual values. In an example embodiment, luminance ratio values and residual values in color channels of a color space are generated on an individual pixel basis based on a high dynamic range (HDR) image and a derivative tone-mapped (TM) image that comprises one or more color alterations that would not be recoverable from the TM image with a luminance ratio image. The TM image with HDR reconstruction data derived from the luminance ratio values and the color-channel residual values may be outputted in an image file to a downstream device, for example, for decoding, rendering, and/or storing. The image file may be decoded to generate a restored HDR image free of the color alterations.