Abstract: A data processing device comprises: a data receiver to receive data to be processed, an external clock, and a unit control signal determining a processing unit for the data to be processed from an outside, the data receiver including a PLL circuit to receive the external clock; a clock abnormality detector to operate based on a clock of a system different from a system of the external clock and detect abnormality of the external clock based on a lock signal output from the PLL circuit; and a data processing controller to control processing of the data. When abnormality of the external clock is detected, the data processing controller stops taking in the data to be processed, and when the external clock becomes normal again, take in the unit control signal and resume taking in the data to be processed.

Abstract: A data processing device includes a data processing circuit and a data processing control circuit. The data processing circuit is configured to perform data processing on processing target data by use of an external clock, the processing target data being included in a data signal received from an outside, the external clock being included in the data signal. The data processing control circuit is configured to detect a state of the external clock and control execution of the data processing on the processing target data in accordance with the state of the external clock. The data processing control circuit is configured to operate with a clock having a lower impedance than an impedance of the external clock, and discard the processing target data received during a period in which an abnormality of the external clock is detected, in a case of detecting the abnormality of the external clock.

Abstract: A document size detection device includes: a light source that irradiates a document placed on placing means with scanning light via the placing means; a reading unit that receives reflection light from the document via the placing means to acquire image data of the document; and circuitry to set an illumination depth of the scanning light at a size detection time when the size is detected, shallower than an illumination depth of the scanning light at an image reading time when an image of the document is read, and detects, at the size detection time, the size based on a difference between first image data acquired in a state in which the scanning light is switched off and second image data acquired in a state in which the scanning light is switched on.

Abstract: A reading device includes: a light source that irradiates a subject with scanning light; a light receiving section that receives reflection light from the subject; and circuitry to: control the light source to switch on and off of the scanning light; control the light receiver to receive the reflection light from the subject for a predetermined acquisition time at a predetermined acquisition interval so as to acquire data; and calculate a difference between the data acquired while the scanning light is switched on and the data acquired while the scanning light is switched off. The predetermined acquisition time and the predetermined acquisition interval are set such that the acquisition time or a total time of the acquisition time and the acquisition interval become an integer multiple of a fluctuation cycle of a fluctuation factor.

Abstract: A document size detection device includes: a light source to irradiate a document with light; an imaging device to receive light reflected at the document; and circuitry to control switch on and off of the light source and movement in a sub-scanning direction of the light source, and determine a size of the document based on image data acquired by the imaging device. The circuitry is to determine a size in a main-scanning direction of the document based on: first image data acquired when the light source is switched off while the light source is at a first reading position; second image data acquired when the light source is switched on while the light source is at the first reading position; and third image data acquired when the light source is switched on while the light source is being moved from the first reading position to a second reading position.

Abstract: A data processing device includes a data processing circuit and a data processing control circuit. The data processing circuit is configured to perform data processing on processing target data by use of an external clock, the processing target data being included in a data signal received from an outside, the external clock being included in the data signal. The data processing control circuit is configured to detect a state of the external clock and control execution of the data processing on the processing target data in accordance with the state of the external clock. The data processing control circuit is configured to operate with a clock having a lower impedance than an impedance of the external clock, and discard the processing target data received during a period in which an abnormality of the external clock is detected, in a case of detecting the abnormality of the external clock.

Abstract: A document size detection device includes: a light source that irradiates a document placed on placing means with scanning light via the placing means; a reading unit that receives reflection light from the document via the placing means to acquire image data of the document; and circuitry to set an illumination depth of the scanning light at a size detection time when the size is detected, shallower than an illumination depth of the scanning light at an image reading time when an image of the document is read, and detects, at the size detection time, the size based on a difference between first image data acquired in a state in which the scanning light is switched off and second image data acquired in a state in which the scanning light is switched on.

Abstract: A reading device includes: a light source that irradiates a subject with scanning light; a light receiving section that receives reflection light from the subject; and circuitry to: control the light source to switch on and off of the scanning light; control the light receiver to receive the reflection light from the subject for a predetermined acquisition time at a predetermined acquisition interval so as to acquire data; and calculate a difference between the data acquired while the scanning light is switched on and the data acquired while the scanning light is switched off. The predetermined acquisition time and the predetermined acquisition interval are set such that the acquisition time or a total time of the acquisition time and the acquisition interval become an integer multiple of a fluctuation cycle of a fluctuation factor.

Abstract: A document size detection device includes: a light source to irradiate a document with light; an imaging device to receive light reflected at the document; and circuitry to control switch on and off of the light source and movement in a sub-scanning direction of the light source, and determine a size of the document based on image data acquired by the imaging device. The circuitry is to determine a size in a main-scanning direction of the document based on: first image data acquired when the light source is switched off while the light source is at a first reading position; second image data acquired when the light source is switched on while the light source is at the first reading position; and third image data acquired when the light source is switched on while the light source is being moved from the first reading position to a second reading position.

Abstract: A signal processing device includes a signal output circuit, a controller, and a corrector. The signal output circuit outputs a signal according to a physical quantity being input. The controller controls the signal output circuit. The corrector corrects a signal to be corrected. The signal to be corrected is output from the signal output circuit. The signal output circuit selectively performs one of first operation of outputting a characteristic signal that indicates characteristics of the signal output circuit and second operation of outputting a pseudo signal that is generated spuriously, according to control of the controller. The corrector corrects the signal to be corrected based on one of the characteristic signal and the pseudo signal output from the signal output circuit.

Abstract: An image capturing apparatus includes: a casing having an opening; a light source arranged inside the casing; a sensor arranged inside the casing and configured to capture, through the opening, an image of an object present outside the casing while the light source is on; and a distance calculator to calculate a distance between the casing and the object, based on an image that has been captured by the sensor and contains, within an image region of the object defined by the opening, a high-luminance region and low-luminance regions located more outside than the high-luminance region.

Abstract: A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

Abstract: A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

Abstract: A signal processing device includes a signal output circuit, a controller, and a corrector. The signal output circuit outputs a signal according to a physical quantity being input. The controller controls the signal output circuit. The corrector corrects a signal to be corrected. The signal to be corrected is output from the signal output circuit. The signal output circuit selectively performs one of first operation of outputting a characteristic signal that indicates characteristics of the signal output circuit and second operation of outputting a pseudo signal that is generated spuriously, according to control of the controller. The corrector corrects the signal to be corrected based on one of the characteristic signal and the pseudo signal output from the signal output circuit.

Abstract: A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

Abstract: An image capturing apparatus includes: a casing having an opening; a light source arranged inside the casing; a sensor arranged inside the casing and configured to capture, through the opening, an image of an object present outside the casing while the light source is on; and a distance calculator to calculate a distance between the casing and the object, based on an image that has been captured by the sensor and contains, within an image region of the object defined by the opening, a high-luminance region and low-luminance regions located more outside than the high-luminance region.

Abstract: A distance measuring device includes: an imaging unit that captures a test pattern image including a pair of first markers and a second marker that is formed under a condition different from a condition applied to the first markers; a position detecting unit that detects a position of each of the pair of first markers and the second marker in a captured image captured by the imaging unit; a ratio calculating unit that calculates a ratio of a distance between the pair of the first markers in the captured image and an actual distance between the pair of the first markers; and an actual distance calculating unit that calculates an actual distance between one of the first markers as the pair and the second marker by multiplying a distance between the one of the first markers as the pair and the second marker in the captured image by the ratio.

Abstract: An image forming apparatus includes a recording head to discharge ink to a recording medium to form an image thereon, an optical sensor to output a signal in response to intensity of reflection of light emitted to the direction of discharging the ink, a carriage that carries the recording head and the optical sensor, and a control unit to detect the position of the recording medium based on the signal output by the optical sensor and control the recording head to discharge the ink only onto the position of the recording medium, wherein the control unit acquires a value according to the signal output by the optical sensor in response to the movement of the carriage and detects the position of the recording medium when a predetermined relation between the value and a threshold continues at least for a predetermined interval in the movement of the carriage.

Abstract: A nozzle testing device includes: a two-dimensional image sensor to capture an image of a pattern formed on a recording object by discharging ink from a nozzle row while moving the nozzle row and the recording object relative to each other in a direction orthogonal to the nozzle row; a light source unit provided such that regularly reflected light by the pattern forms a regular reflection area in the image of the pattern captured by the two-dimensional image sensor; and a detection unit to analyze the image to detect discharge failure of the nozzles. The regular reflection area is formed in the image such that a dimension in a direction corresponding to the direction of relative movement between the nozzle row and the recording object is greater than a dimension in a direction orthogonal to the direction corresponding to the direction of relative movement in the image.

Abstract: An image forming apparatus includes a printing unit that prints at least one object image using a color material; a color information acquiring unit that acquires color information of the object image; and a control unit that starts one of colorimetry of the object image using the color information acquired by the color information acquiring unit and color adjustment of the printing unit after a variation amount of color information of the object image measured at different points of time is equal to or smaller than a predetermined threshold.