504 results about "Tone mapping" patented technology

Techniques for creating a High Dynamic Range (HDR) image within a consumer grade digital camera from a series of images of a scene captured at different exposure levels, and displaying the HDR image on the camera's built-in display, are provided. The approach employs mixing images of the series to incorporate both scene shadow and highlight details, and the removing of “ghost” image artifacts appearing in the mixed HDR image resulting from movement in the scene over the time the series images are captured. The low computational resource utilization of the present invention's image mixing and ghost removal processing operations, along with the present invention's ability to commence image mixing and ghost removal prior to the acquisition of all series images, can significantly reduce the time required to generate and display a tone mapped HDR image.

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.

An apparatus, method, computer useable medium, and processor programmed to automatically generate tone mapping curves in a digital camera based on image metadata are described. Rather than having a static tone mapping curve for all images, the curve can be varied automatically based on, e.g., the brightness histogram of the image. In one embodiment, a certain percentage of the least bright pixels and a certain percentage of the brightest pixels can be disregarded, while the remaining pixels can be linearly stretched to encompass the original range of brightness values. Based on the distribution of the resultant stretched brightness histogram, slopes for the low end (S₀) and high end (S₁) of the tone mapping curve can be independently determined, and the tone mapping curve can be automatically generated. The improved, automatically generated tone mapping curve may be able to lift shadows more aggressively and/or increase the dynamic range of the image.

Video processing techniques and pipelines that support capture, distribution, and display of high dynamic range (HDR) image data to both HDR-enabled display devices and display devices that do not support HDR imaging. A sensor pipeline may generate standard dynamic range (SDR) data from HDR data captured by a sensor using tone mapping, for example local tone mapping. Information used to generate the SDR data may be provided to a display pipeline as metadata with the generated SDR data. If a target display does not support HDR imaging, the SDR data may be directly rendered by the display pipeline. If the target display does support HDR imaging, then an inverse mapping technique may be applied to the SDR data according to the metadata to render HDR data for display. Information used in performing color gamut mapping may also be provided in the metadata and used to recover clipped colors for display.

The present invention relates to a method capable of real-time implementable local tone mapping of high dynamic range images. In one embodiment, the present invention relates to a method capable of accomplishing real-time local tone mapping of high dynamic range images so that they have clear details without, for example, halo artifacts when viewed on standard display devices. In another embodiment, the present invention relates to a method capable of accomplishing real-time local tone mapping of high dynamic range images so that they have clear details without, for example, halo artifacts when viewed on standard display devices where such a method utilizes, in part, a modified Reinhard operator.

A system and process for generating High Dynamic Range (HDR) video is presented which involves first capturing a video image sequence while varying the exposure so as to alternate between frames having a shorter and longer exposure. The exposure for each frame is set prior to it being captured as a function of the pixel brightness distribution in preceding frames. Next, for each frame of the video, the corresponding pixels between the frame under consideration and both preceding and subsequent frames are identified. For each corresponding pixel set, at least one pixel is identified as representing a trustworthy pixel. The pixel color information associated with the trustworthy pixels is then employed to compute a radiance value for each pixel set to form a radiance map. A tone mapping procedure can then be performed to convert the radiance map into an 8-bit representation of the HDR frame.

A method for processing high dynamic range (HDR) images by selecting preferred tone mapping operators and gamut mapping algorithms based on scene classification. Scenes are classified into indoor scenes, outdoor scenes, and scenes with people, and tone mapping operators and gamut mapping algorithms are selected on that basis. Prior to scene classification, the multiple images taken at various exposure values are fused into a low dynamic range (LDR) image using an exposure fusing algorithm, and scene classification is performed using the fused LDR image. Then, the HDR image generated from the multiple images are tone mapped into a LDR image using the selected tone mapping operator and then gamut mapped to the color space of the output device such as printer.

The invention discloses a system and a method for processing image data using an image signal processor. Disclosed embodiments provide for a an image signal processing system (32) that includes back-end pixel processing unit (120) that receives pixel data after being processed by at least one of a front-end pixel processing unit (80) and a pixel processing pipeline (82). In certain embodiments, the back-end processing unit (120) receives luma/chroma image data and may be configured to apply face detection operations, local tone mapping, bright, contrast, color adjustments, as well as scaling. Further, the back-end processing unit (120) may also include a back-end statistics unit (2208) that may collect frequency statistics. The frequency statistics may be provided to an encoder (118) and may be used to determine quantization parameters that are to be applied to an image frame.

The ratio between coding quality on the one hand and coding rate on the other hand is increased. To this end, a global predictor and a local predictor are used in combination. The global predictor derives a global tone-mapping function based on a statistical analysis of pairs of values of co-located samples in the first tone-mapped version and the second version of the picture, and applies the global tone-mapping function onto the first tone-mapped version of the picture. The local predictor locally derives a locally varying tone-mapping function based on a statistical analysis of values of co-located samples in the second version of the picture and the globally predicted reference picture in units of sub-portions into which the globally predicted reference picture and the second version of the picture are partitioned, and applies the locally varying tone-mapping function onto the globally predicted reference picture.

A method for brightness and contrast enhancement includes computing a luminance histogram of a digital image, computing first distances from the luminance histogram to a plurality of predetermined luminance histograms, estimating first control point values for a global tone mapping curve from predetermined control point values corresponding to a subset of the predetermined luminance histograms selected based on the computed first distances, and interpolating the estimated control point values to determine the global tone mapping curve. The method may also include dividing the digital image into a plurality of image blocks, and enhancing each pixel in the digital image by computing second distances from a pixel in an image block to the centers of neighboring image blocks, and computing an enhanced pixel value based on the computed second distances, predetermined control point values corresponding to the neighboring image blocks, and the global tone mapping curve.

A method of producing a compressed video data stream (12) by compressing a stream of relatively high dynamic range video frames (2). A bilateral filter (3) extracts a base frame (4) with luminance information. The base frame (4) and the original frame (2) are used to provide a detail frame (5) with chroma information. A tone mapping operation (6) is selected (7, 11) and applied to the base frame to generate a relatively low dynamic range base frame (8), which is then compressed (9). The detail frame (5) is compressed separately. Final frame data (12) is then created, consisting of the compressed relatively low dynamic range base frame, the compressed detail frame, and stored information in respect of the tone mapping operation that had been applied to the base frame.

An image processing method and apparatus for obtaining a wide dynamic range image, the method including: obtaining a plurality of low dynamic range images having different exposure levels for a same scene; generating motion map representing whether motion occurred, depending on brightness ranks of the plurality of low dynamic range images; obtaining weights for the plurality of low dynamic range images; generating a weight map by combining the weights and the motion map; and generating a wide dynamic range image by fusing the plurality of low dynamic range images and the weight map. According to the image processing method and apparatus, it is possible to accurately detect motion area using a rank map, obtain a wide dynamic range image at a higher operation speed, and reduce a possibility that a phenomenon such as color warping occurs by directly combining images without using a tone mapping process.

The invention discloses a real-time drafting and displaying method of highly dynamic scope image, which comprises the following steps: 1) remaining highly dynamic scope information when drafting scene; 2) calculating the average brightness of image; filtering the brightness of image according to the threshold; generating new image with high-brightness filtered area; proceeding two-dimensional Gauss fuzzy for new image; generating glow effect; 3) mapping color tone of image with highly dynamic scope information; displaying the image with highly dynamic scope information to display in the low dynamic scope; keeping details as many as possible; 4) generating final image after do alpha mixing the color tone mapped image and fuzzy image. The invention reduces the calculation quantity, which satisfies the drafting need with good practical value.