def __call__(self, results):
        """
        Performs Image to NumpyArray operations.
        Args:
            imgs: List where each item is a PIL.Image.
            For example, [PIL.Image0, PIL.Image1, PIL.Image2, ...]
        return:
            np_imgs: Numpy array.
        """
        imgs = results['imgs']
        if 'backend' in results and results[
                'backend'] == 'pyav':  # [T,H,W,C] in [0, 1]
            if self.transpose:
                if self.data_format == 'tchw':
                    t_imgs = imgs.transpose((0, 3, 1, 2))  # tchw
                else:
                    t_imgs = imgs.transpose((3, 0, 1, 2))  # cthw
            results['imgs'] = t_imgs
        else:
            t_imgs = np.stack(imgs).astype('float32')
            if self.transpose:
                if self.data_format == 'tchw':
                    t_imgs = t_imgs.transpose(0, 3, 1, 2)  # tchw
                else:
                    t_imgs = t_imgs.transpose(3, 0, 1, 2)  # cthw
            results['imgs'] = t_imgs
        return results

        Performs Image to NumpyArray operations.
        Args:
            imgs: List where each item is a PIL.Image.
            For example, [PIL.Image0, PIL.Image1, PIL.Image2, ...]
        return:
            np_imgs: Numpy array.
        
deploy/pipeline/pphuman/video_action_preprocess.py