For X-data: The CXR images of COVID-19 cases collected from the public CCD52 contained 212 patients diagnosed with COVID-19 and were resized to 512 × 512. Each image contained 1–2 suspected areas with inflammatory lesions (SAs). We also collected 5100 normal cases and 3100 pneumonia cases from another public data set (RSNA)53. In addition, The CXR images collected from the Youan hospital contained 45 cases diagnosed with COVID-19, 503 normal cases, 435 cases diagnosed with pneumonia (not COVID-19 patients), and 145 cases diagnosed as influenza. The CXR images collected from the Youan hospital were obtained using the Carestream DRX-Revolution system. All the CXR images of COVID-19 cases were analyzed by the two experienced radiologists to determine the lesion areas. The X-data of the normal cases (XNPDS), that of the pneumonia cases (XPPDS), and that of the COVID-19 cases (XCPDS) from public data sets constituted the X public data set (XPDS). The X-data of the normal cases (XNHDS), that of the pneumonia cases (XPHDS), and that of the COVID-19 cases (XCHDS) from the Youan hospital constituted the X hospital data set (XHDS).