Abstract: A first separation distance is determined between a first pair of defects in a scanned image of a first printed sheet, and a second separation distance is determined between a second pair of defects in a scanned image of a second printed sheet. The defects are determined as having a separation distance in that the first and second separation distances are each within a first threshold of a specified separation distance and/or a difference between the first and second separation distances is below a second threshold. A source of the defects can be determined based on the characteristic separation distance.

Abstract: Examples of the present disclosure relate to a method for skew detection in a printing system. The method comprises printing a document from an original digital image, scanning the document to produce a digital representation using an in line scanner of the printing system, and detecting skew in the digital representation independently from the original digital image.

Abstract: Examples of the present disclosure relate to a method for skew detection in a printing system. The method comprises printing a document from an original digital image, scanning the document to produce a digital representation using an in line scanner of the printing system, and detecting skew in the digital representation independently from the original digital image.

Abstract: A method is disclosed. The method may comprise obtaining first image data representing a reference image to be printed on a substrate. The method may comprise obtaining second image data representing a scanned image of a substrate on which the reference image has been printed. The method may comprise combining the first image data and the second image data to generate combined image data. The method may comprise providing the combined image data as an input to a classifier component to identify a difference between the first image data and the second image data. An apparatus and a machine-readable medium are also disclosed.

Abstract: A first separation distance is determined between a first pair of defects in a scanned image of a first printed sheet, and a second separation distance is determined between a second pair of defects in a scanned image of a second printed sheet. The defects are determined as having a separation distance in that the first and second separation distances are each within a first threshold of a specified separation distance and/or a difference between the first and second separation distances is below a second threshold. A source of the defects can be determined based on the characteristic separation distance.

Abstract: In one example of the disclosure, a set of scanned images is accessed. The scanned images are scans of distinct printouts of subject images produced utilizing an intermediate transfer member. A set of defect maps is created by comparing the scanned images to reference data for the subject images. The set of defect maps are combined into an integrated defect map. A dent defect on the ITM is identified utilizing the integrated defect map.

Abstract: A method for processing an image is disclosed. The method may include obtaining a target image to be printed using print agent in a printable area of a substrate of a particular colour. The method may include obtaining a scanned image of a substrate on which the target image has been printed, the substrate being of the particular colour. The method may include determining, from the scanned image, the particular colour of the substrate. The method may include using the target image as a reference image against which the scanned image is to be compared. The method may include adjusting a colour in the reference image according to the determined particular colour of the substrate. An apparatus and a machine-readable medium are also disclosed.

Abstract: In an example, a method includes determining, by a processor, a cumulative indication of defects present in linear sub-portions located in a common position of each of a plurality of substrate sheets bearing a printed image. The method may further comprise identifying, by the processor, a linear defect based on the cumulative indication of defects.

Abstract: In an example, a method includes determining, by a processor, at least one separation distance between defects in a scanned image of a printed substrate sheet bearing a printed image, wherein the separation distance determined in a predetermined direction. The method may further comprise determining, by the processor, if the defects have a characteristic separation distance.

Abstract: In one example of the disclosure, a set of scanned images is accessed. The scanned images are scans of distinct printouts of subject images produced utilizing an intermediate transfer member. A set of defect maps is created by comparing the scanned images to reference data for the subject images. The set of defect maps are combined into an integrated defect map. A dent defect on the ITM is identified utilizing the integrated defect map.

Abstract: A method is described in which an image is received, the image including a document and background area; a candidate location of a boundary between the document and the background area is found; and a validity of the candidate location of the boundary is checked, based on pixel values around the candidate location of a first channel of the image, and pixel values around the candidate location of at least one other channel of the image, wherein the at least one other channel is different from the first channel.

Abstract: A method for processing an image is disclosed. The method may include obtaining a target image to be printed using print agent in a printable area of a substrate of a particular colour. The method may include obtaining a scanned image of a substrate on which the target image has been printed, the substrate being of the particular colour. The method may include determining, from the scanned image, the particular colour of the substrate. The method may include using the target image as a reference image against which the scanned image is to be compared. The method may include adjusting a colour in the reference image according to the determined particular colour of the substrate. An apparatus and a machine-readable medium are also disclosed.

Abstract: A monitoring device includes circuitry to compare a printed output with a reference representing a target output and to determine potential defects in the printed output based on the comparison. The monitoring device further includes and circuitry to implement a convolutional neural network to classify each potential defect as a true defect or a false alarm.

Abstract: In one example of the disclosure, a set of scanned images is accessed. The scanned images are scans of distinct printouts of subject images produced utilizing a photo imaging plate. A set of defect maps is created by comparing the scanned images to reference data for the subject images. The set of defect maps are combined into an integrated defect map. A scratch defect on the PIP is identified utilizing the integrated defect map.

Abstract: Examples analyze a digital image to determine an amount of high-frequencies corresponding to each pixel of the digital image based at least in part on gradients corresponding to a pixel neighborhood of each pixel. Examples analyze the digital image to determine a degree of randomness for each pixel based at least in part on the corresponding gradients. Examples generate an activity mask for the digital image based at least in part on the amount of high-frequencies and the degree of randomness corresponding to each pixel. Examples process the pixels of the digital image by performing gray component replacement to generate a color transformed image based at least in part on the activity mask.

Abstract: In one example of the disclosure, a set of scanned images is accessed. The scanned images are scans of distinct printouts of subject images produced utilizing a photo imaging plate. A set of defect maps is created by comparing the scanned images to reference data for the subject images. The set of defect maps are combined into an integrated defect map. A scratch defect on the PIP is identified utilizing the integrated defect map.

Abstract: In an example, a method includes determining, by a processor, a cumulative indication of defects present in linear sub-portions located in a common position of each of a plurality of substrate sheets bearing a printed image. The method may further comprise identifying, by the processor, a linear defect based on the cumulative indication of defects.

Abstract: In an example, a method includes determining, by a processor, at least one separation distance between defects in a scanned image of a printed substrate sheet bearing a printed image, wherein the separation distance determined in a predetermined direction. The method may further comprise determining, by the processor, if the defects have a characteristic separation distance.

Abstract: Examples analyze a digital image to determine an amount of high-frequencies corresponding to each pixel of the digital image based at least in part on gradients corresponding to a pixel neighborhood of each pixel. Examples analyze the digital image to determine a degree of randomness for each pixel based at least in part on the corresponding gradients. Examples generate an activity mask for the digital image based at least in part on the amount of high-frequencies and the degree of randomness corresponding to each pixel. Examples process the pixels of the digital image by performing gray component replacement to generate a color transformed image based at least in part on the activity mask.

Abstract: Apparatus to detect a defect in a printed image and methods of detecting detects in a printed image are described. In some examples, a printing operation is initiated using image data to generate a printed image. The printed image is then scanned to generate a scanned image. A resolution of the scanned image is estimated, calculated or determined on the basis of a characteristic of the printing operation, and a reference image, having a resolution corresponding to the estimated, calculated or determined resolution, is generated from the image data. Whether defects are present in the printed image may be determined on the basis of a comparison of the reference image with the scanned image.