The University of British Columbia

Dolby Laboratories Licensing Corporation

Rabab K Ward

Robin Atkins

Pingnan Shi

Qin Zhang

Panos Nasiopoulos

Zicong Mai

Julong Du

Xiaoli Li

Qiaobing Xie

In one embodiment, a dual modulator display systems and methods for rendering target image data upon the dual modulator display system are disclosed where the display system receives target image data, possible HDR image data and first calculates display control signals and then calculates backlight control signals from the display control signals. This order of calculating display signals and then backlight control signals later as a function of the display systems may tend to reduce clipping artifacts. In other embodiments, it is possible to split the input target HDR image data into a base layer and a detail layer, wherein the base layer is the low spatial resolution image data that may be utilized as for backlight illumination data. The detail layer is higher spatial resolution image data that may be utilized for display control data.

Systems and methods for controlling dual modulation displays

System and methods for controlling dual modulation displays

Several embodiments of an efficient tone mapping of high bit depth video to low bit depth displays are disclosed. In one embodiment, a system maps an input image data of a high dynamic range (HDR) onto output image data of a lower dynamic range (LDR) and where the mapping does not transform the input image data from one color space to another color space. One embodiment comprises a tone mapping module which outputs a tone-mapped luminance signal for output image data and a color mapping module which outputs chroma signals for the output image data. Intermediate image processing steps may be avoided and hence may increase the efficiency of the mapping.

Efficient tone-mapping of high-bit-depth video to low-bit-depth display

A method of reducing noise in video signal, by processing the pixels of a process frame of video signal in conjunction with a selected number of previously processed frames to determine values for target pixels in the process frame by applying a temporal motion detector to determine whether a target pixel has a still or motion status and further processing the pixels with motion status by impulse recognition step to further determine whether the pixel should be classified as having a still or a motion status. The pixels are then checked via a spatial motion detecting step to obtain a motion index value to the pixels and the motion index value is used in a motion adaptive temporal filter to define the pixel value of the still pixel. The motion index value of the pixels is used to set a dynamic threshold in a detailed motion active spatial filter to define the pixel value for the motion pixels. The system may be integrated with a converter box for converting digital signals to analog for use in conjunction with analog television sets services by digital signals.

Noise reduction for video signals

A method for determining the composite triple beat (CTB), composite second order beat (CSO) and/or SNOW noise of cable television signal is obtained by digitizing a quiet line and determining the Fourier transform of the digitized signal and measuring the energy in the frequency range corresponding to the particular impairment of being determined. Repeating this process a significant number of time to accumulate a significant number N of values for the impairment and then using the average of the accumulated intensity to define the amount of the impairment.

Measurement of noise impairments of TV signals

The system for reducing composite beat, composite second order beat and thermal (snow) noise impairments in a television system digitizes individual frames to apply digitized a grey scale values (v.sub.(i,j)) to the pixels in the frames and then applying a spatial filter to a block of pixels including the then current pixel being processed to determine the pixel (P.sub.(min)) with the minimum grey scale value (v.sub.(min)) and the pixel (P.sub.(max)) in the block with the maximum grey scale value (v.sub.(min)). V.sub.(max) -v.sub.min is compared with a threshold value (v.sub.(T)) and if v.sub.(max) -v.sub.min) &gt;v.sub.(T), the value (v.sub.(i,j)) of the pixel being processed remains unchanged, but if v.sub.(max)-v.sub.(min).notgreaterthan.v.sub.(T), a value (v.sub.(av.)) equal to the weighted average value of pixels in the block is used as the grey scale value v.sub.(R-i,j) for the pixel being processed. The block preferably, will be composed of a number of adjacent pixels in a row or a number of adjacent pixels in a column or both processed simultaneously or preferably in sequence i.e. the pixels processed along the rows and then along the columns with the values assigned to the pixels when processing along the rows used as the initial values for the pixels when processing along the columns. In more preferred cases, a plurality of frames are each subject to static filtering and then the adjacent frames in the sequence are subject to time filtering (provided motion is not detected) to provide a better average value vZ.sub.(mean) for the processed pixel in the specific frame being processed.

System for reducing beat type impairments in a TV signal

A method of determining the noise content of a video signal by digitizing a frame based on the video signal to provide a digitized signal which is then filtered via a high pass filter. The filtered image is then divided into a plurality of subimages and the noise signal in each of the subimages is determined from a selected number of subimages having the lowest noise signal are further processed to determine the average noise in the selected subimages and the signal-to-noise ratio determined. The carrier-to-noise ratio may also be determined if desired.

System for determining noise content of a video signal in the disclosure

A method for reducing the effect of a composite triple beat (CTB) of a visual image is obtained by digitizing the signal for the image frame, dividing the digital signal into a plurality of stripes extending perpendicular to the horizontal lines of the image to form subpictures and determining the average intensity of the signal in each of the horizontal lines of each of the subpictures. An average value for each of the lines in each of the subpictures is then obtained and the component of the signal forming the composite triple beat signal for each line of each subpicture is estimated. Then the estimated triple beat signal is subtracted from its corresponding portion of the digitized signal to provide corrected subpictures. The corrected subpictures are then recombined to form a clean signal providing the cleaned visual image. In a preferred arrangement plurality of consecutive frames are treated as above described to provide average corrections for each line based on the average for the corresponding lines in the subpictures in the plurality of frames and then the subpictures for the frame to be shown next are corrected using the average corrections values to provide an even clearer signal.

Signal correction for composite triple beat impairments

A cable television signal for example may be monitored and impairments determined and in many cases classified by grabbing at least portion of a transmitted frame of video information somewhere on the network to provide a video signal, performing a two dimensional Fourier transform on the video signal and analyzing the Fourier transform so obtained to determine the location of areas indicating above average occurrence of specific frequencies to provide an indication of an impairment.

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Vancouver, Canada

Rabab K Ward