Abstract: 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.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: An embodiment generally relates to systems and methods for determining cell phone usage automatically by individuals operating vehicles. A processing module can process multi-spectral images or videos of individuals and detect different regions in the image such as face regions, hand regions, and cell phone regions. Further, the processing module can analyze the regions based on locations and numbers of skin pixels and cell phone pixels to determine if the individual is holding his or her cell phone near his or her face. Based on the analysis, it can be determined whether the individual is operating the cell phone. Further, the analysis can yield a confidence level associated with the cell phone usage.

Abstract: A method for calibrating in situ a plurality of printheads in an imaging device has been developed. Firing signals operate a plurality of printheads to form ink test patterns on an image receiving member. Reflectance measurements of light reflected from the test patterns and optical density measurements for a portion of the patterns formed by only one printhead in the plurality of printheads are used to adjust the firing signals and enable the printheads to print within a predetermined range about an average reflectance value and a predetermined optical density.

Abstract: A method enables an inkjet printing system to attenuate image noise in an image of a test strip obtained as print media bearing the test strip travels over a roller in the printing system.

Abstract: A method evaluates image quality in an ink printing system and generates data values for altering the operation of the ink printing system. The method includes generating an ink image on an ink image receiving member that corresponds to a digital image stored in the ink printing system, generating a scanned image signal corresponding to the ink image, generating firing signal waveform adjustments and image data adjustments with reference to the scanned image signal corresponding to the ink image, and operating a printhead in an ink imaging system with reference to the firing signal waveform adjustments and the image data adjustments.

Abstract: A printer operating method enables a controller to identify process direction errors in an optical imaging system. The method includes identifying a printhead roll error for each printhead in a plurality of printheads in a printer, moving each printhead by an amount that corrects the printhead roll error for the corresponding printhead, generating a plurality of dashes on media with the plurality of printheads as the media moves past the plurality of printheads, identifying a position for each dash in the process direction from image data of the plurality of dashes on the media, identifying a displacement in the process direction for each optical detector in a linear array of optical detectors used to generated the image data of the plurality of dashes, the displacement being identified with reference to the identified positions for the dashes, and operating the printer to compensate for the identified displacements of the optical detectors.

Abstract: A color correction method includes for each of a plurality of color separations of a digital image, establishing a tone reproduction curve in the form of a vector. The vector is a function of a plurality of basis vectors. The basis vectors account for colorant interactions between a primary colorant with which the color separation is to be rendered and at least one secondary colorant with which at least a second of the plurality of color separations is to be rendered. The vector includes modified input values corresponding to input values for the color separation which vary, depending on the input values of at least the second color separation. For a pixel of interest in the digital image, a modified input value for the color separation which corresponds to the input value of the given color separation is identified from the vector.

Abstract: A printer operating method enables a controller to identify process direction errors in an optical imaging system. The method includes identifying a printhead roll error for each printhead in a plurality of printheads in a printer, moving each printhead by an amount that corrects the printhead roll error for the corresponding printhead, generating a plurality of dashes on media with the plurality of printheads as the media moves past the plurality of printheads, identifying a position for each dash in the process direction from image data of the plurality of dashes on the media, identifying a displacement in the process direction for each optical detector in a linear array of optical detectors used to generated the image data of the plurality of dashes, the displacement being identified with reference to the identified positions for the dashes, and operating the printer to compensate for the identified displacements of the optical detectors.

Abstract: A test pattern printed by printheads in an inkjet printer enables image analysis of the test pattern that identifies positions of the printheads and the inkjets operating in the printheads. The test pattern includes a plurality of arrangements of dashes, each arrangement of dashes having a predetermined number of rows and a predetermined number of columns, each dash in a row of dashes in the arrangement of dashes being separated by a first predetermined distance and each dash in a column of dashes in the arrangement of dashes being separated by a second predetermined distance, each dash in a column of an arrangement of dashes being ejected by a single inkjet ejector in a printhead of the inkjet printer, and a plurality of unprinted areas interspersed between the plurality of arrangements of dashes.

Abstract: A system removes a light sensor artifact from a light sensor in a printer that is used to obtain reflectance measurements from test patterns printed on an image substrate.

Abstract: A method enables an inkjet printing system to attenuate image noise in an image of a test strip obtained as print media bearing the test strip travels over a roller in the printing system.

Abstract: This closure provides image processing methods and apparatus for corner enhancing a digital image for rendering on an image output device. According to an exemplary method, the method determines whether or not image pixels are associated with a corner as a function of the USAN values generated for the image pixels. Subsequently, one or more pixels associated with a corner are modified to render a corner enhanced image.

Abstract: What is disclosed is a novel system and method for reducing process color banding due to printhead non-uniformities in a direct marking device. In one example, a first measurement of a printhead spatial non-uniformity is obtained along a first line in a color space which produces a spatial uniformity when a target primary color is printed alone. A first spatial tone reproduction curve is generated. A second measurement of the printhead spatial non-uniformity is obtained along a second line in color space in a coverage area of a process color which maximally changes a halftone structure of the target primary color. A second spatial TRC is generated. The first and second spatial TRCs are combined using a weighted average which balances the primary and process colors. A modified spatial TRC is generated. The printhead is adjusted at a location of the target primary color according to the modified spatial TRC.

Abstract: A color transformation method which accounts for colorant interactions includes establishing a plurality of tone reproduction curves (TRCs), for one or more of the color separations forming a digital image. Each TRC accounts for colorant interactions between a primary colorant with which the first color separation is to be rendered and at least one secondary colorant with which at least a second of the plurality of color separations is to be rendered. The TRCs include input values and their corresponding modified input values. In a given TRC, the input values of the second and optionally other color separations are fixed. For a pixel of the digital image having a given input values for the first and second color separation one or more of the TRCs are selected which bound the fixed input value for the second color separation and a modified input value is determined therefrom.

Abstract: A method evaluates image quality in an ink printing system and generates data values for altering the operation of the ink printing system. The method includes generating an ink image on an ink image receiving member that corresponds to a digital image stored in the ink printing system, generating a scanned image signal corresponding to the ink image, generating firing signal waveform adjustments and image data adjustments with reference to the scanned image signal corresponding to the ink image, and operating a printhead in an ink imaging system with reference to the firing signal waveform adjustments and the image data adjustments.

Abstract: Images that include halftone structures are sharpened. A copy of received halftone image data is blurred, thereby reducing a detectability of edges of the halftone structures. Edges remaining in the blurred image data are detected. An edge enhancement image is generated based on the detected edges. The original received halftone image data is combined with the edge enhancement image, thereby generating sharpness enhanced image data having halftone structures. The sharpness enhanced image data having halftone structures can be rendered through a halftone screen that is compatible with a halftone screen that was used to generate the originally received image data. Alternatively, the sharpness enhanced image data having halftone structures is rendered according to error diffusion techniques, such as, rank order error diffusion in order to achieve or maintain dot or halftone structure compaction.

Abstract: A method for encoding high resolution data to a form having a reduced number of bits can include predefining a plurality of high-output-resolution output patterns, associating respective output-resolution output patterns of the plurality with respective encoded resolution bit patterns, receiving a block of input-resolution input data, determining a respective difference between a pattern of the received block of input data and the respective output-resolution output patterns, selecting a respective output-resolution output pattern associated with a lowest respective difference to be a representative output pattern for the received block of input data and encoding the received block of input-resolution input data as the respective encoded resolution bit pattern associated with the selected respective representative high-output-resolution output pattern. A system includes a library of output patterns in association with encoded resolution bit patterns, a block analyzer, a block selector and an encoder.

Abstract: Image data is scaled, rotated and/or otherwise manipulated. Diffusive effects of associated interpolation and/or re-sampling are compensated for, or corrected, by applying an adaptive packing form of error diffusion to output data of one or more manipulating transforms. For example, rank order error diffusion is applied to output data of a manipulating transform, thereby restoring compaction to otherwise diffuse halftone structures (e.g., halftone dots, lines, etc), saturated text and/or other small, high contrast image elements.

Abstract: What is disclosed is a novel system and method for reducing process color banding due to printhead non-uniformities in a direct marking device. In one example, a first measurement of a printhead spatial non-uniformity is obtained along a first line in a color space which produces a spatial uniformity when a target primary color is printed alone. A first spatial tone reproduction curve is generated. A second measurement of the printhead spatial non-uniformity is obtained along a second line in color space in a coverage area of a process color which maximally changes a halftone structure of the target primary color. A second spatial TRC is generated. The first and second spatial TRCs are combined using a weighted average which balances the primary and process colors. A modified spatial TRC is generated. The printhead is adjusted at a location of the target primary color according to the modified spatial TRC.