A printing apparatus includes a head capable of discharging CMYK inks including a K ink, and a control unit configured to, based on image data to be printed, generate ink amount data for controlling an ink amount of each of the CMYK inks discharged by the head, and to control the head based on the ink amount data, wherein the control unit generates the ink amount data as ink amount data such that lightness of a composite color at least does not increase in a direction from a freely-selected coordinate point toward a black point, the composite color being formed by the CMY inks excluding the K ink based on ink amount data of each of the CMYK inks corresponding to a coordinate on a straight line from the freely-selected coordinate point toward the black point in a predetermined hue range of a color gamut of a color space of the image data.

A printing apparatus includes a head capable of discharging CMYK inks including a K ink, and a control unit configured to, based on image data to be printed, generate ink amount data for controlling an ink amount of each of the CMYK inks discharged by the head, and to control the head based on the ink amount data, wherein the control unit generates the ink amount data as ink amount data such that lightness of a composite color at least does not increase in a direction from a freely-selected coordinate point toward a black point, the composite color being formed by the CMY inks excluding the K ink based on ink amount data of each of the CMYK inks corresponding to a coordinate on a straight line from the freely-selected coordinate point toward the black point in a predetermined hue range of a color gamut of a color space of the image data.

An image forming apparatus includes a setting unit configured to set an operation mode, and a processing unit configured to perform image processing on image data according to the operation mode. In a case when a first mode is set, the image processing includes determining, in the image data, one or more target pixels having a gradation value equal to or higher than a first threshold value, and one or more adjacent pixels that are different from the one or more target pixels and adjacent to the one or more target pixels, setting a first gradation value lower than the first threshold value as a gradation value of the one or more target pixels, and setting a second gradation value higher than the first gradation value as a gradation value of the one or more adjacent pixels.

An image forming apparatus includes an output unit, a reading unit, and a processor. The output unit outputs multiple types of charts. The reading unit reads images of the charts. The charts are output by the output unit. The processor performs multiple types of processes in a predetermined order in accordance with the images of the charts and original images used to output the charts. Each of the processes is at least one of diagnosis and adjustment. The images of the charts are obtained through the reading operation performed by the reading unit. The charts which are output by the output unit include a diagnostic chart for a spot and/or a streak and a diagnostic chart for transfer. After the processor performs a first diagnosis based on the diagnostic chart for a spot and/or a streak, the processor performs a second diagnosis based on the diagnostic chart for transfer.

An image processing apparatus that generates a combined image by performing gamma processing and combination processing for a plurality of images obtained by capturing images of the same image capturing-target scene under different exposure conditions and includes: an acquisition unit configured to acquire adjustment parameters that adjust gamma characteristics applied to the gamma processing in accordance with a dynamic range of the image capturing-target scene; a gamma processing unit configured to perform the gamma processing to which adjustment parameters acquired by the acquisition unit have been applied for the plurality of images; and a combination unit configured to generate the combined image by performing the combination processing for the plurality of images for which the gamma processing has been performed by the gamma processing unit.

An image processing apparatus includes an image analyzing unit, a tone-curve generating unit, and an image correcting unit. The image analyzing unit acquires a model parameter by modeling data distribution of an image with a probability distribution model. The tone-curve generating unit generates a tone curve on the basis of control information in which the model parameter acquired by modeling the data distribution of the image to be processed is associated with a target value of the model parameter. The image correcting unit corrects the image to be processed by using the generated tone curve.

An image processing apparatus includes an image analyzing unit, a tone-curve generating unit, and an image correcting unit. The image analyzing unit acquires a model parameter by modeling data distribution of an image with a probability distribution model. The tone-curve generating unit generates a tone curve on the basis of control information in which the model parameter acquired by modeling the data distribution of the image to be processed is associated with a target value of the model parameter. The image correcting unit corrects the image to be processed by using the generated tone curve.

An image reading device includes a first setting processing portion, a second setting processing portion, and a third setting processing portion. The first setting processing portion, when first reference data has been read in a first reading process in which image data is read from a sheet placed on a sheet placement portion, sets a first adjustment value which is used in a shading correction. The second setting processing portion, when second reference data has been read in a second reading process in which image data is read from a sheet conveyed by a sheet conveying portion, sets a second adjustment value which is used in the shading correction. The third setting processing portion, in a case where only one of the first adjustment value and the second adjustment value has been set, sets the other based on the one that has been set.

An image reading apparatus according to an embodiment of the present invention includes: an image sensor to read a document; a movement unit configured to relatively move the document and the image sensor by using a motor as a drive source; an output unit configured to output data of a plurality of colors based on accumulated light-receiving signals by accumulating the light-receiving signals from the image sensor for each color in order for each line in a direction of the movement based on an encoder pulse output from an encoder in accordance with rotation of the motor; and a correction unit configured to perform shading correction for each piece of data of the plurality of colors output by the output unit by using a correction value to correct influence on data of the plurality of colors due to a dark current in the image sensor based on shading data.

An image reading apparatus according to an embodiment of the present invention includes: an image sensor to read a document; a movement unit configured to relatively move the document and the image sensor by using a motor as a drive source; an output unit configured to output data of a plurality of colors based on accumulated light-receiving signals by accumulating the light-receiving signals from the image sensor for each color in order for each line in a direction of the movement based on an encoder pulse output from an encoder in accordance with rotation of the motor; and a correction unit configured to perform shading correction for each piece of data of the plurality of colors output by the output unit by using a correction value to correct influence on data of the plurality of colors due to a dark current in the image sensor based on shading data.