714 results about "Error diffusion" patented technology

Embodiments are directed to image processing methods to improve display quality while using a limited number of pulses and to correct the error between the reflectance and the desired gamma. The complexity of the hardware used for driving a display device may then be reduced to minimum. In addition, in various embodiments the method can also be used to compensate for the change of an optical response curve due to batch variation, temperature change, photo-exposure or aging of the display device.

Compensation for rendering device non-uniformities is provided for halftoned images. A spatially dependent tone reproduction curve (TRC) provides compensation values. Pixel location information is used to access TRC values. For example, the values are modification values. The modification values are added to the pixel values to generate combined values. Quantization is applied to the combined values to prepare compensated image data for rendering. For example, Rank Ordered Error Diffusion is applied to the combined values. The combined values may include diffused error from previously processed pixels. Gray values may be estimated for the respective pixels. The estimated gray values may be used to access compensation information from a TRC that is both spatially and gray value dependent. Mathematical basis decomposition is used to reduce TRC memory requirements. For example, Discrete Cosine Transformation, Singular Value Decomposition or Principal Component Analysis is used to determine a compact form for the TRC.

An image processing apparatus can obtain a copy image having excellent reproducibility with a relatively simple structure of a processing unit that processes image data. The image processing apparatus generates image formation data by processing image data. A gradation processing unit binarizes the image data according to an error diffusion process so as to convert the image data into binary image data. A character / line drawing detection unit determines whether a part of the binary image data corresponds to a character / line drawing portion that consists of characters or line drawings so as to detect the character / line drawing portion. An image processing unit applies an image processing to the part of the binary image data by using an image processing method according to a result of determination of the character / line drawing detection unit.

The present invention appropriately determines the on / off state of dots having different hues in a printer using at least two inks of different hues, thereby enhancing the quality of printing. The system of the present invention applies the systematic dither method to determine whether or not dots are to be formed by ink of a predetermined hue, for example, magenta. In the case of formation of dots by magenta ink, the system drives a piezoelectric element PE disposed on a head corresponding to the magenta ink to form magenta dots and calculates a resulting value MRST. In the case of non-formation of dots by the magenta ink, on the other hand, the resulting value MRST is set equal to zero. The system then applies the technique of error diffusion to determine whether or not dots are to be formed by cyan ink, based on the tone data of the cyan ink. The structure of the present invention enables a difference between density data M(x,y) of the magenta ink and its resulting value MRST to affect density data of the cyan ink. This makes it difficult to form dots of cyan ink in the vicinity of dots of magenta ink.

An image processing method for executing a quantization process of image data by error diffusion, executes a step of generating first image data by adding a quantization error to input image data, a step of generating second image data by quantizing the first image data by comparing the first image data with a predetermined threshold value, a step of generating third image data by dequantizing the second image data, a calculation step of calculating a quantization error for each pixel on the basis of the difference between the first and third image data, a storage step of storing information indicating a positive / negative sign of the calculated quantization error for a predetermined number of pixels in a storage unit, and a correction value generation step of generating a correction value used to correct at least one of the first image data and the threshold value on the basis of the information which is stored in the storage unit and indicates the positive / negative sign.

A video signal processing apparatus processes an input video signal for displaying an image based on the video signal. Detected is a gradation level of the input video signal. A color saturation level of the input video signal is depressed in a predetermined color saturation level range only when the detected gradation level is located in a predetermined gradation level range. A first input video signal having a first gradation level (or number of bits) is converted into a second video signal having a second gradation level (or number of bits) that is lower (or smaller) than first gradation level (or number of bits), for displaying an image based on the input video signal. Error data is generated in response to a data portion of the first input video signal. The data portion corresponds to a difference between the first and the second gradation levels (or number of bits). The error data is obtained by multiplying the data portion by predetermined error diffusion coefficients according to pixel dots that surround a pixel dot composed of R(red)-, G(green)- and B(blue)-signal components of the first input video signal. At least one of the number of bits of the error diffusion coefficients for one of the R-, G- and B-signal components is different from the other number of bits of the error diffusion coefficients for the other signal components The generated error data is added to the first input video signal to convert the first input video signal into the second video signal. Reverse-gamma correction may be applied to the first input video signal before conversion.

A method for processing a digital color image for display and transmission includes the steps of (a) resizing the image to a lower display resolution to produce a display-sized image, (b) quantizing the display-sized image to a display palette with an error diffusion process to produce an error diffused image, (c) losslessly compressing the error diffused image to produce a compressed image having a particular file size, (d) comparing the file size to a maximum file size and if less than the maximum file size, transmitting the digital image to the display; (e) if the file size is greater than the maximum file size but less than a another predetermined file size, reducing the error diffusion rate by a predetermined amount in order to reduce the file size; and (f) if the file size is greater than the maximum file size and the predetermined file size, simplifying the resized image by reducing image detail to produce a simplified image and repeating the preceding steps on the simplified image.

Disclosed are methods of halftoning images having multiple color planes using error diffusion techniques, and incorporating both error information from the previously-processed color planes of a pixel, and error information from a previously process pixel of yet-to-be processed color planes.

Error is distributed to pixels neighboring a pixel of interest based on a ranking of the neighboring pixels. The ranking is based on pixel values of the neighboring pixels. Optionally a spatial weighting is applied to the pixel values before ranking, to provide a preference for pixels closest to the pixel of interest or to a particular portion of a related halftone screen. Rank order based error diffusion provides compact halftone dots without patterning artifacts. An image processing system operative to perform rank order error diffusion includes a pixel ranker and an error diffuser. In a xerographic environment the image processing system includes a xerographic printer.

The invention provides 16-step dual-frequency grating phase shift profilometry capable of absolute phase unwrapping in the three-dimensional sensor technology. The invention is characterized by usingcomputers to design codes to generate 16 dual-frequency grating patterns, using a digital light projector to image the grating patterns on the surface of an object instantaneously in sequence, using apick-up device to record the deforming fringe pattern of the object, subsequently using the functional relationship between the gratings with two frequencies, using the absolute phase unwrapping method to directly realize phase unwrapping of point to point in the whole field range and having no relation with the path for phase unwrapping, effectively inhibiting accumulative error diffusion, usingphase measuring profilometry to process the deforming fringes, accurately restoring the three-dimensional shape of the object and obtaining such digital information as deformation of the object and the like by further analyzing the data processing results. The method can be used for measurement study of the characteristics of the object surface with the characteristic of diffuse reflection. The method has the advantages of high measurement precision and strong adaptability to the surface topography of the object, etc.

A method of adjusting a TRC of an image is provided. The method involves receiving an image at an input resolution, resampling the image to a processing resolution if the imput resolution and the processing resolution are not same, processing the image using rank-ordered error diffusion, and resampling the processed image to a desired output resolution for the image if the processing resolution and the output resolution are not same.

The invention relates to a method for adjusting the error diffusion of an LED (Light Emitting Diode) dynamic backlight, which comprises the steps of: reading the backlight data of a backlight subarea; judging the position of surrounding subareas of the subarea; reading the backlight data of the surrounding subareas of the subarea; judging whether the sum of the data of the subarea and a threshold value is less than the maximum data of the surrounding subareas; if so, the new backlight data of the subarea is equal to the sum of the original backlight data of the subarea and the multiplication product of the surrounding subareas backlight data with a diffusion coefficient K; if not, keeping the backlight data of the subarea unchanged, that is to say, the new backlight data of the subarea is equal to the original backlight data of the subarea. By obfuscating the backlight data of an image, the invention solves the defects that vision is influenced seriously by the sliding of a backlight shadow on a screen when brightness difference between adjacent backlight subareas is too large in dynamic backlight.

A printing apparatus of the present invention prints an image corresponding to image data, which are divided into a plurality of pages and supplied from an application program, on a roll of machine glazed paper without any margin set between the adjoining pages. This arrangement enables printing on a large-sized printing medium, such as a banner. A printer driver incorporated in the printing apparatus causes the image data divided into the plurality of pages to be subjected to halftone processing according to an error diffusion method. When a standard printing mode is specified, an error buffer is initialized on every instruction of a new page. When a continuous printing mode is specified, on the other hand, the error buffer is not initialized. This causes an error occurring in a certain pixel included in one page to be diffused to pixels included in a next page in the continuous printing mode. The arrangement of the present invention enables the image data divided into a plurality of pages to be collectively processed by the halftone processing and thereby improves the picture quality of the image especially in the vicinity of a boundary between the adjoining pages.

A page-wide array inkjet printer allocates the processing tasks for individual printheads within the array to separate halftoning processors. Each halftoning processor processes the information relating to a strip of the image, with the boundaries between strips running parallel to the print medium advance direction. In a preferred embodiment, the pixels within each strip are processed using a forward error diffusion algorithm operating along columns of pixels parallel to the strip boundaries. The resulting halftone data is supplied from each halftoning processor to one or more uniquely associated printing component controllers, and these controllers generate print instructions for printing components (e.g. inkjet printheads) connected to the printing component controllers via a dedicated communications channel.

A method of embedding digital watermarks such as logos, letters or other types of user information into printed documents using different halftone textures. By alternating different halftone methods, such as different halftone screens or different error diffusion algorithms during the halftoning process, digital watermarks can be embedded into the input images at run time. The actual watermark is created by changing—on a pixel basis—the halftoning algorithm that is used in rendering the input image. No modifications to the input image are needed and the image data is reproduced correctly, but with a visible seem between different halftoning techniques.

The invention relates to an adaptive H.264 compressed domain video watermark embedding and extracting method in the technical field of information security, which can realize the real-time operation of video information hiding. The threshold value of a motion vector is adaptively adjusted according to watermark embedding amount statistical data of an adjacent frame, so that watermark capacity is ensured and the requirement of embedding a one-time watermark among a few frames is met; and error diffusion caused by modifying the motion vector is accurately positioned in a partial interframe prediction mode, so that good drift and distortion compensation effects can be achieved.

The invention provides a method of burying additional information in an image, which can suppress deterioration of image quality and reduce an extraction error rate when extracting the additional information. For implementing the method, in an image processing apparatus for burying predetermined information in a color image, the apparatus comprises an input unit for inputting a color image; a quantizing unit for quantizing the input color image with an error diffusion process for each of predetermined color components; and a quantizing condition control unit for controlling, in accordance with the predetermined information, periodicity at which an amplitude of a quantizing threshold is modulated by the quantizing unit. The quantizing condition control unit controls a phase in the amplitude modulation of the quantizing threshold to be different between at least one of the color components and the other color components.

A watermarked halftone image is generated from a continuous tone image by performing error diffusion halftoning on the continuous tone image while adding a watermark to the halftone image during the halftoning. A location of the watermark in the halftone image may be based on prediction criteria. Error caused by adding the watermark may be diffused into the halftone image.

The invention provides a printing method of printing on a printing medium. The method includes: generating dot data that represents state of dot formation at each print pixel of a print image to be formed on the printing medium by performing a halftone process on image data that represents an input tone value of each pixel making up an original image; providing a print head capable of selectively forming N types of dots having mutually different sizes on a region of one pixel on the printing medium, N being an integer of at least 2; and generating the print image according to the dot data by mutually combining a plurality of dot groups in a common print region, each of the plurality of dot groups being formed on each of a plurality of pixel groups that assume mutually physical differences in a process of dot formation. The generating dot data includes: executing the halftone process by using an error diffusion method with respect to smaller-size-side dot among the N types of dots; and executing the halftone process by using a dither method with respect to larger-size-side dot among the N types of dots, a condition of halftone process of the dither method being set such that all of the dot groups have a first predetermined characteristic.

An image processing system including a lookup table having multi-bit printer output levels and an imaging input level. The imaging input level may be associated with a range of input pixel densities. The system further includes a processor configured to compare the imaging input level with one or more preconfigured threshold output values associated with the printer output levels. The imaging input level may be preferentially weighted to select a printer output level having an increased bit depth.

The present invention discloses a strapdown inertial combination measurement control device applicable to all-fibre digital clinometer, it is used for measuring well course of oil well and gas well, in particular it is applicable to conventional measurement with line and measurement while drilling. Said control device adopts strapdown inertial navigation principle, and utilizes main navigation system formed from optical-fibre gyroscope and anti-vibration accelerometer, under the condition of different working environments and measurement accuracy requirements respectively utilizes several external information of logging cable rope length, flux-gate sensor and zero speed and combines kalman filter so as to make system error estimation and correction of main inertial navigation system, and can limit error diffusion of inertial navigation system and form a high-accuracy combination inertial measurement instrument.

An apparatus (1100) for halftoning an image is disclosed. The apparatus comprises means for determining an output value of a current pixel on a current scanline using a sum of an input value (1102) for the current pixel and a neighborhood error value (1150) at the current pixel, means (1124) for determining an error at the current pixel as the difference between (i) the sum of the input value (1102) for the current pixel and the neighborhood error value (1150) at the current pixel, and (ii) the output value (1120) of the current pixel; and means (1140) for adding a proportion of the error at the current pixel to neighborhood error values at as yet unprocessed pixels of a subsequent scanline in accordance with a next scanline error impulse response; wherein said next scanline error impulse response approximates a function which spreads with self-convolution in proportion to a degree of self-convolution.

Tone dependent plane dependent error diffusion halftoning takes into account multiple color planes, such as cyan and magenta, when determining the placement of a dot in any of the color planes. The combined tones of the correlated color planes is used to determine the threshold levels against which the combined tones and the accumulated errors for the correlated color planes is compared. Further, tone dependent error weightings are determined based on the combined tones of the correlated color planes. The tone dependent error weightings are used to diffuse the final accumulated errors for each color plane. A prerendered mid-tone bitmap may be used to break up any structured patterns that occur in the mid-tones. Using this technique, printed dots of two or more colors are dispersed so as to avoid noticeable clumping of dots of two or more colors to provide a more uniform pattern and to avoid the unintentional overlapping of colors. This technique can be used to augment any existing error diffusion method.

The generation of dot data of planes depending on a plurality of scannings and ink colors in an ink jet printing apparatus is performed based on the error diffusion processing for each plane without causing a problem of grain. Specifically, in a binarization processing, C divided data D8c / 2 is subjected to an error diffusion processing to calculate binary (dot) data D2c1 for the first pass of C. Next, M divided data D8m / 2 is compensated by being added with a term of Kc1m1(D8c / 2-D2c1). Then, this compensated data [D8m / 2+Kc1m1(D8c / 2-D2c1)] is subjected to an error diffusion processing to calculate dot data D2m1 for the first pass of M. In this manner, the generation of the respective planes performs correction to reflect the results of the binarization processing of the respective previously processed planes to subject the compensated data to an error diffusion processing.

Image processing apparatus and image processing method for formation of high quality image by high-speed error diffusion processing by execution of more complicated threshold condition processing in a simple manner. When error diffusion processing is performed on multivalued image data having plural density components and the result of processing is outputted, upon execution of error diffusion processing on a first density component among the plural density components, a threshold value used in the error diffusion processing is determined based on a density value of a second density component, then the error diffusion processing is performed on the first density component based on the determined threshold value, and the result of execution of the error diffusion processing is outputted. Further, upon execution of the error diffusion processing on the second density component among the plural density components, a threshold value used in the error diffusion processing is determined based on a density value of the first density component, then the error diffusion processing is performed on the second density component based on the determined threshold value, and the result of the error diffusion processing is outputted.

A method of adjusting a TRC of an image is provided. The method involves receiving an image at an input resolution, resampling the image to a processing resolution if the imput resolution and the processing resolution are not same, processing the image using rank-ordered error diffusion, and resampling the processed image to a desired output resolution for the image if the processing resolution and the output resolution are not same.

For improving the grey scale portrayal, several dithering methods are used: Cell-based dithering, multi-mask dithering or error diffusion. Each of them has specific disadvantages. A simple combination of them does not bring expected advantages. However, an improvement is obtained if the result of the multi-mask dithering is used for controlling the error diffusion by a switch, for example.