Repository: Project-MONAI/MONAI

Issue:
RandRicianNoise not working with relative argument as True
**Describe the bug**
When using the transform RandRicianNoise and the relative argument is set to True, an error occurs.

**To Reproduce**
Steps to reproduce the behavior:
1. Compose the transforms, with the only transform being RandRicianNoise. The relative argument should be True, while the other argument can be anything.
2. Apply the transforms to an image that is a tensor.

**Expected behavior**
The transformation should be applied to the image that is a tensor

**Screenshots**
![image](https://user-images.githubusercontent.com/68797723/206201347-ea40966f-7f1b-445b-bb0c-2caa7a890bb6.png)

**Environment**
```
================================
Printing MONAI config...
================================
MONAI version: 1.1.0rc1+13.g6fa4bce1.dirty
Numpy version: 1.23.4
Pytorch version: 1.13.0
MONAI flags: HAS_EXT = False, USE_COMPILED = False, USE_META_DICT = False
MONAI rev id: 6fa4bce1961d84f89c243f27c093054396ee4557
MONAI __file__: C:\Users\Nisha\OneDrive\Documents\GitHub\MONAI\monai\__init__.py

Optional dependencies:
Pytorch Ignite version: NOT INSTALLED or UNKNOWN VERSION.
Nibabel version: 4.0.2
scikit-image version: 0.19.3
Pillow version: 9.2.0
Tensorboard version: NOT INSTALLED or UNKNOWN VERSION.
gdown version: NOT INSTALLED or UNKNOWN VERSION.
TorchVision version: 0.14.0
tqdm version: 4.64.1
lmdb version: NOT INSTALLED or UNKNOWN VERSION.
psutil version: 5.9.0
pandas version: NOT INSTALLED or UNKNOWN VERSION.
einops version: NOT INSTALLED or UNKNOWN VERSION.
transformers version: NOT INSTALLED or UNKNOWN VERSION.
mlflow version: NOT INSTALLED or UNKNOWN VERSION.
pynrrd version: NOT INSTALLED or UNKNOWN VERSION.

For details about installing the optional dependencies, please visit:
    https://docs.monai.io/en/latest/installation.html#installing-the-recommended-dependencies


================================
Printing system config...
================================
System: Windows
Win32 version: ('10', '10.0.22621', 'SP0', 'Multiprocessor Free')
Win32 edition: Core
Platform: Windows-10-10.0.22621-SP0
Processor: AMD64 Family 25 Model 33 Stepping 2, AuthenticAMD
Machine: AMD64
Python version: 3.9.15
Process name: python.exe
Command: ['python']
Open files: [popenfile(path='C:\\Windows\\System32\\en-US\\kernel32.dll.mui', fd=-1), popenfile(path='C:\\Windows\\System32\\en-US\\KernelBase.dll.mui', fd=-1)]
Num physical CPUs: 6
Num logical CPUs: 12
Num usable CPUs: 12
CPU usage (%): [3.9, 10.9, 3.7, 3.7, 5.7, 5.9, 20.5, 15.2, 13.4, 10.5, 7.4, 9.0]
CPU freq. (MHz): 3501
Load avg. in last 1, 5, 15 mins (%): [0.0, 0.0, 0.0]
Disk usage (%): 60.8
Avg. sensor temp. (Celsius): UNKNOWN for given OS
Total physical memory (GB): 15.9
Available memory (GB): 0.8
Used memory (GB): 15.2

================================
Printing GPU config...
================================
Num GPUs: 1
Has CUDA: True
CUDA version: 11.7
cuDNN enabled: True
cuDNN version: 8500
Current device: 0
Library compiled for CUDA architectures: ['sm_37', 'sm_50', 'sm_60', 'sm_61', 'sm_70', 'sm_75', 'sm_80', 'sm_86', 'compute_37']
GPU 0 Name: NVIDIA GeForce RTX 3060 Ti
GPU 0 Is integrated: False
GPU 0 Is multi GPU board: False
GPU 0 Multi processor count: 38
GPU 0 Total memory (GB): 8.0
GPU 0 CUDA capability (maj.min): 8.6
```


Discussion:

Resolving patch:
diff --git a/monai/transforms/intensity/array.py b/monai/transforms/intensity/array.py
--- a/monai/transforms/intensity/array.py
+++ b/monai/transforms/intensity/array.py
@@ -207,7 +207,7 @@ def __call__(self, img: NdarrayOrTensor, randomize: bool = True) -> NdarrayOrTen
                 raise RuntimeError("If channel_wise is False, mean must be a float or int number.")
             if not isinstance(self.std, (int, float)):
                 raise RuntimeError("If channel_wise is False, std must be a float or int number.")
-            std = self.std * img.std() if self.relative else self.std
+            std = self.std * img.std().item() if self.relative else self.std
             if not isinstance(std, (int, float)):
                 raise RuntimeError("std must be a float or int number.")
             img = self._add_noise(img, mean=self.mean, std=std)


Test patch: