CROSS REFERENCE TO RELATED APPLICATIONS

The entire disclosure of Japanese patent Application No. 2019-108819, filed on Jun. 11, 2019, is incorporated herein by reference in its entirety.

BACKGROUND

Technical Field

The present invention relates to an evaluation device and an evaluation method.

Description of Related Art

Hitherto, in order to detect the glossy feel of a print image formed on a recording medium by an image forming apparatus, a device that measures the glossiness or the image clarity of a print image has been known. The glossiness is a physical quantity that indicates the specular reflectance of an object with respect to incident light that is incident thereupon at a predetermined angle. The image clarity is referring to texture corresponding to the sharpness of a reflected image that is projected onto an object, and is indicated by the visual impression of a user.

For example, Japanese Patent Application Laid-Open No. 2001-99632 discloses a structure in which a standard pattern, which is an object, is projected onto a rough object to obtain image data related to a reflected image of the standard pattern, and, based on a parameter related to the image data, the magnitude of a fluctuation of the reflected image is calculated. In this structure, the surface property of the rough object is calculated based on the calculated value.

Japanese Patent Application Laid-Open No. 2015-194490 discloses a structure in which a specularly reflected image of an image confirmed as not being abnormal is a standard image, and, in the specularly reflected image of a print image to be evaluated, a portion that differs from the standard image is detected as a defect. In this structure, a physical quantity of the same nature as glossiness is detected.

However, even if the glossinesses at the surfaces of a plurality of print images are the same, the visual impression of a user may differ for each print image. Therefore, it is desired that the glossy texture of the print images be evaluated by detecting the image clarity instead of the glossiness of the print images.

The structure described in Japanese Patent Application Laid-Open No. 2001-99632 has a property in that since the magnitude of the fluctuation of the reflected image is calculated based on the reflected image of the standard pattern, the sensitivity with respect to the image clarity of a recording medium used for printing is poor.

Japanese Patent Application Laid-Open No. 2015-194490 has a property in that since the step of confirming an image serving as a standard image is required, the evaluation step of evaluating the glossy texture of the print images cannot be automated, and the evaluation step becomes complicated.

SUMMARY

One or more embodiments of the present invention provide an evaluation device and an evaluation method that are capable of automatically detecting the image clarity of print images and accurately evaluating the image clarity of the print images.

One or more embodiments of the present invention provide an evaluation device that evaluates an image clarity of a print image, the evaluation device comprising:

an object that is projected onto a print image surface which is a measurement surface of a recording medium;

an illuminator that allows the object to be projected onto the measurement surface;

an imager that images the measurement surface on which the object has been projected; and

a hardware processor that, based on a distribution of parameters related to a brightness of image data imaged by the imager, quantifies a degree of the image clarity into a numerical value and defines the numerical value as an evaluation value of the image clarity.

One or more embodiments of the present invention provide an evaluation method that evaluates an image clarity of a print image in an evaluation device including an object that is projected onto a print image surface which is a measurement surface of a recording medium, and an illuminator that allows the object to be projected onto the measurement surface, the evaluation method comprising:

imaging the measurement surface on which the object has been projected; and

based on a distribution of parameters related to a brightness of image data imaged by the imager, quantifying a degree of the image clarity into a numerical value and defining the numerical value as an evaluation value of the image clarity.

