Fix val.py study plot (#4831)

* Fix val.py study plot

* call plot_val_study

* Rename plot_study_txt to plot_val_study

val.py

@@ -26,7 +26,7 @@ from utils.general import coco80_to_coco91_class, check_dataset, check_img_size,
     check_suffix, check_yaml, box_iou, non_max_suppression, scale_coords, xyxy2xywh, xywh2xyxy, set_logging, \
     increment_path, colorstr
 from utils.metrics import ap_per_class, ConfusionMatrix
-from utils.plots import plot_images, output_to_target, plot_study_txt
+from utils.plots import output_to_target, plot_images, plot_val_study
 from utils.torch_utils import select_device, time_sync
 from utils.callbacks import Callbacks
 
@@ -348,7 +348,7 @@ def main(opt):
                 y.append(r + t)  # results and times
             np.savetxt(f, y, fmt='%10.4g')  # save
         os.system('zip -r study.zip study_*.txt')
-        plot_study_txt(x=x)  # plot
+        plot_val_study(x=x)  # plot
 
 
 if __name__ == "__main__":