CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese application JP 2020-016465, filed on Feb. 3, 2020 and Japanese application JP 2020-016466, filed on Feb. 3, 2020. These Japanese applications are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a display device, a method for displaying image data and mobile terminal. The present disclosure particularly relates to a display device and the like suitable for displaying a medical image on a mobile terminal.

BACKGROUND

Conventionally, various technologies have been proposed as display devices for image interpretation in which a medical image such as a tomographic image is observed and diagnosed (e.g., see Unexamined Japanese Patent Publication No. 2019-103944). In Unexamined Japanese Patent Publication No. 2019-103944, in order to improve efficiency in image interpretation, graph information on a tomographic image is generated, and a graph marker is superimposed on the graph information.

SUMMARY

However, with an increase in number of diagnoses, a sharp increase in amount of image information, a shortage of doctors, and the need to reform doctors' work styles in recent years, it has been required to be able to interpret images by use of mobile terminals not only at hospitals but also at home and on business trips.

However, regarding display of medical images, a gradation characteristic has been determined by Grayscale Standard Display Function (GSDF) defined in the Digital Imaging and Communications in Medicine (DICOM) standard. At this time, as an index for evaluating whether an image is compliant with GSDF, a contrast-response error rate, which is an error rate between a contrast calculated from ideal GSDF and a measured value, is used. However, the contrast-response error rate fluctuates under the influence of illuminance in an environment where a display device is placed. Hence it is difficult for a display device used in various environments, such as a mobile terminal, to maintain a gradation characteristic compliant with GSDF.

This present disclosure provides a display device and a method for displaying image data that are suitable for displaying a medical image on a mobile terminal.

This present disclosure also provides a mobile terminal and a method for calibrating a mobile terminal that can maintain a gradation characteristic suitable for displaying a medical image.

A display device for displaying image data according to the present disclosure includes: a gradation conversion circuit that converts a gradation of input image data; a display panel that displays the image data with the gradation converted by the gradation conversion circuit; an illuminance sensor that detects illuminance of an environment where the display device is placed; and a gamma characteristic corrector that controls a gradation conversion circuit so as to convert the gradation by use of a gamma characteristic corresponding to the detected illuminance.

A method for displaying image data according to the present disclosure includes: a gradation conversion step of converting a gradation of the image data input into a display device; a display step of displaying the image data with the gradation converted in the gradation conversion step; an illuminance detection step of detecting illuminance of an environment where the display device is placed; and a gamma characteristic correction step of performing control so as to convert the gradation by use of a gamma characteristic corresponding to the detected illuminance.

A mobile terminal according to the present desclosure, includes: a display panel; and an opening and closing unit linked to the display panel so as to be switchable between a first position for exposing a front surface of the display panel and a second position for covering the front surface, wherein the opening and closing unit has at least one luminance sensor that is a luminance sensor attached to a surface of the opening and closing unit facing the front surface when at the second position, and that detects luminance of the front surface.

A method for calibrating the mobile terminal according to the present disclosure includes: a luminance calibration step of performing calibration of a gamma characteristic of the mobile terminal in accordance with the luminance detected by the at least one luminance sensor, wherein in the luminance calibration step, the calibration is performed when the opening and closing unit shifts from the first position to the second position.

