Abstract:
Methods are disclosed for adaptive display management using one or more viewing environment parameters. Given the one or more viewing environment parameters, an effective luminance range for a target display, and an input image, a tone-mapped image is generated based on a tone-mapping curve, an original PQ luminance mapping function, and the effective luminance range of the display. Corrected PQ (PQ') luminance mapping functions are generated according to the viewing environment parameters and, optionally, the transmissivity properties and reflectivity properties of the target display. PQ-to-PQ' mappings are generated, where each corrected (PQ') luminance mapping function is associated with a different set of viewing environment parameters and is associated with a different region of the display and where codewords in the original PQ luminance mapping function are mapped to codewords in the corrected (PQ') luminance mapping functions, and an adjusted tone-mapped image is generated based on the PQ-to-PQ' mappings.
Abstract:
There is provided a video signal processing apparatus, including: a first interface configured to obtain a first video signal imaged within a first dynamic range; a second interface configured to obtain information for specifying a partial area of the obtained first video signal; and an arithmetic processing circuit configured to calculate a representative value of brightness of the first video signal of the partial area, to compress a dynamic range of the first video signal depending on the calculated representative value, and to generate a second video signal, a dynamic range of the second video signal being restricted to a second dynamic range narrower than the first dynamic range.
Abstract:
A method and a camera system for improving the contrast of a camera image comprising an evaluation of the brightness distribution of the image and application of a contrast correction function to the image. In order to improve the contrast for difficult lighting conditions the spatial brightness distribution is determined, whereas the contrast correction function is varied depending on the spatial brightness distribution.
Abstract:
The present invention relates to apparatus and method for automatically computing a gamma correction curve. The apparatus according to the present invention comprises an image obtaining unit for receiving an input image data of a color chart through an image interface; a coordinate calculating unit for measuring input brightness values of a plurality of ROIs (Regions of Interest) of the input image and comparing an input brightness value of each ROI with a preset target brightness value of each ROI to calculate gamma correction coordinates for a plurality of points of a gamma correction curve; and a curve computing unit for applying interpolation to a plurality of the calculated gamma correction coordinates to compute a gamma correction curve.
Abstract:
In the technical field of video cameras gamma correction is an often used technique to compensate the non-linear effects of the CRT (cathode ray tube), in order to enhance visibility in images to be displayed. Gamma correction is -by way of example- expressed by the gamma function: A process for enhancing detail visibility in an input image comprising a step of applying a first transfer function (11) to the input image, thereby generating an intermediate image; a step of performing a statistical measurement (12), Mmt (2) on the intermediate image; a step of applying a second transfer function (14) to the intermediate image, thereby generating an output image; a step of performing a statistical measurement (15), Mmt (3) on the output image, a step of determining gain parameters gg, gk for the first and the second transfer function (11, 14) on basis of the statistical measurement results (8, 12, 15), Mmt (1), Mmt (2), Mmt (3) is proposed.
Abstract:
The invention relates to a video circuit (1) for processing video signals which show images on a display panel with linear light transition, comprising a gamma correction circuit (3), a quantizer (11) and a sub-field generator circuit (8). To save computing time, a random-access memory (7) replaces the quantizer (64).
Abstract:
A gamma correction circuit for correcting a digital video signal, the circuit comprising first (6) and second (8) lookup tables for storing discrete output intensity data and the associated slope data of a non-linear transfer function, respectively, for each of the discrete input video signal intensities, an adder (10) having a first input connected to the output of the first lookup table, a multiplier (12) having a first input connected to the output of the second look-up table (8), characterized by a quantizer (4) for providing the most significant bits of the incoming video signal to address the first (6) and second (8) lookup tables and to transfer the corresponding output intensity data to the adder (10) and the associated slope data to the multiplier (12), the quantizer (4) transmitting the remaining least significant bits of the input video signal to the second input of the multiplier (12), the multiplier (12) multiplying the slope data with the remaining least significant bits and feeding the multiplication result to the second input of the adder (10), the adder (10) adding the output intensity data and the multiplication result to generate a corrected video signal.