An image processing method, comprising: acquiring a first undersampled image to be processed (202, 306); and reconstructing, according to a mapping relationship between an undersampled image and a normally sampled original image, the first undersampled image to a corresponding first original image, wherein the mapping relationship is obtained by training a machine learning model with a second undersampled image and a normally sampled second original image corresponding to the second undersampled image as training samples (204, 308); wherein the image processing method is characterized by further comprising: downsampling the second original image to obtain the second undersampled image; and training the machine learning model with the second undersampled image and the second original image as training samples to obtain the mapping relationship; wherein the first undersampled image is obtained in the following manner: receiving, by a first group of detectors disposed opposite to a first emitter, rays emitted by the first emitter and penetrating cross sections along a second direction of a first detected object moving along a first direction; and generating the first undersampled image based on the rays received by the first group of detectors, wherein the first direction is perpendicular to the second direction, and the first group of detectors comprises one or more rows of first detectors; wherein the second original image is obtained in the following manner: receiving, by a second group of detectors disposed opposite to a second emitter, rays emitted by the second emitter and penetrating cross sections along a fourth direction of a second detected object moving along a third direction; and generating the second original image based on the rays received by the second group of detectors, wherein the third direction is perpendicular to the fourth direction, and the second group of detectors comprises one or more rows of second detectors; wherein the first undersampled image has a size smaller than that of the first original image in the first direction. acquiring a first undersampled image to be processed (202, 306); and reconstructing, according to a mapping relationship between an undersampled image and a normally sampled original image, the first undersampled image to a corresponding first original image, wherein the mapping relationship is obtained by training a machine learning model with a second undersampled image and a normally sampled second original image corresponding to the second undersampled image as training samples (204, 308); wherein the image processing method is characterized by further comprising: downsampling the second original image to obtain the second undersampled image; and training the machine learning model with the second undersampled image and the second original image as training samples to obtain the mapping relationship; downsampling the second original image to obtain the second undersampled image; and training the machine learning model with the second undersampled image and the second original image as training samples to obtain the mapping relationship; wherein the first undersampled image is obtained in the following manner: receiving, by a first group of detectors disposed opposite to a first emitter, rays emitted by the first emitter and penetrating cross sections along a second direction of a first detected object moving along a first direction; and generating the first undersampled image based on the rays received by the first group of detectors, wherein the first direction is perpendicular to the second direction, and the first group of detectors comprises one or more rows of first detectors; receiving, by a first group of detectors disposed opposite to a first emitter, rays emitted by the first emitter and penetrating cross sections along a second direction of a first detected object moving along a first direction; and generating the first undersampled image based on the rays received by the first group of detectors, wherein the first direction is perpendicular to the second direction, and the first group of detectors comprises one or more rows of first detectors; wherein the second original image is obtained in the following manner: receiving, by a second group of detectors disposed opposite to a second emitter, rays emitted by the second emitter and penetrating cross sections along a fourth direction of a second detected object moving along a third direction; and generating the second original image based on the rays received by the second group of detectors, wherein the third direction is perpendicular to the fourth direction, and the second group of detectors comprises one or more rows of second detectors; wherein the first undersampled image has a size smaller than that of the first original image in the first direction.