# Callback error updating image
**URL:** https://community.plotly.com/t/callback-error-updating-image/60287
**Category:** Dash Python
**Tags:** question
**Created:** [January 21, 2022, 12:02am UTC](https://community.plotly.com/t/callback-error-updating-image/60287 "2022-01-21T00:02:43Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@iromi](https://community.plotly.com/u/iromi)
#### Post date: [January 21, 2022, 12:02am UTC](https://community.plotly.com/t/callback-error-updating-image/60287/1 "2022-01-21T00:02:43Z")
Hi all,
I have mat files containing data of the PET/CT scans. I use an upload function to load mat files. Then based on the user inputted threshold values function suppose to create a figure and should display the figure using graph. Please note that all the images are as nd array. I tried almost all the methods and I am kind of new to dash.
My original layout worked like this:
```auto
html.Div(
[
dcc.Graph(
id="image-display-graph",
figure=fig
)
],
style={
"grid-column": "1",
"grid-row": "2",
"background-color": DISPLAY_BG_COLOR,
},
),
```
And the callback I was doing:
```auto
@app.callback(
Output('image-display-graph', 'figure'),
Input('btn_clicks', 'n_clicks'),
State('hut', 'value'),
State('suvt', 'value'),
State('upload_file', 'filename')
)
```
And the function to get the segmented figure I was doing:
```auto
def make_seg_image(filename, hu, suvt, btn_clicks):
data = read_mat(os.path.join('D:\data', filename))
if 'pt_image' in data:
ct_image = data['ct_image']
pt_image = data['pt_image']
mid_slice_pt = np.round(np.array(pt_image.shape) / 2).astype(int)
pt_slice = pt_image[:, :, mid_slice_pt[2]]
mid_slice_ct = np.round(np.array(ct_image.shape) / 2).astype(int)
ct_slice = ct_image[:, :, mid_slice_ct[2]]
# ct_segmentation
threshold_ct_img = ct_slice > hu
# Apply PET image to CT bone mask
pet_mask = np.multiply(pt_slice, threshold_ct_img)
pt_image_suvt = pet_mask > suvt
fig = px.imshow(pt_image_suvt, animation_frame=0, facet_col=1, binary_string=True)
return fig
```
But I am continuously getting callback errors
---
### Author:  [@Eduardo](https://community.plotly.com/u/Eduardo)
#### Post date: [January 21, 2022, 10:18am UTC](https://community.plotly.com/t/callback-error-updating-image/60287/2 "2022-01-21T10:18:45Z")
Hi @iromi
Add the ERROR message to understand where the problem is.
---
### Author:  [@iromi](https://community.plotly.com/u/iromi)
#### Post date: [January 21, 2022, 11:44am UTC](https://community.plotly.com/t/callback-error-updating-image/60287/3 "2022-01-21T11:44:51Z")
Hi, I got this error
**Callback error updating image-display-graph.figure**
**TypeError: join() argument must be str, bytes, or os.PathLike object, not 'int’**
**## Traceback _(most recent call last)_**
\*\*\* #### File “C:\Users\Iromi\anaconda3\envs\tensorflow\_GPU\Lib\ntpath.py”, line _91_ , in `join`\*\*
**for p in map(os.fspath, paths):**
\*\*\* During handling of the above exception, another exception occurred:\*\*
\*\*\* #### File “C:\Users\Iromi\anaconda3\envs\tensorflow\_GPU\Lib\genericpath.py”, line _152_ , in `_check_arg_types`\*\*
**raise TypeError(f’{funcname}() argument must be str, bytes, or '**
**\> TypeError: join() argument must be str, bytes, or os.PathLike object, not 'int’**
**Traceback (most recent call last):**
\*\* File “C:\Users\Iromi\anaconda3\envs\tensorflow\_GPU\Lib\ntpath.py”, line 91, in join\*\*
\*\* for p in map(os.fspath, paths):\*\*
**TypeError: expected str, bytes or os.PathLike object, not int**
**During handling of the above exception, another exception occurred:**
**Traceback (most recent call last):**
\*\* File “C:\Users\Iromi\anaconda3\envs\tensorflow\_GPU\Lib\genericpath.py”, line 152, in \_check\_arg\_types\*\*
\*\* raise TypeError(f’{funcname}() argument must be str, bytes, or '\*\*
**TypeError: join() argument must be str, bytes, or os.PathLike object, not 'int’**
Thanks
---
### Author:  [@jlfsjunior](https://community.plotly.com/u/jlfsjunior)
#### Post date: [January 21, 2022, 12:12pm UTC](https://community.plotly.com/t/callback-error-updating-image/60287/4 "2022-01-21T12:12:04Z")
Hi,
If `make_seg_image` is your callback, then the arguments order is wrong and `filename` is the click counter (that’s why `os.path.join` is complaining about an int type).
The signature should be `make_seg_image(btn_clicks, hu, suvt, filename)`.
---
### Author:  [@iromi](https://community.plotly.com/u/iromi)
#### Post date: [January 21, 2022, 1:05pm UTC](https://community.plotly.com/t/callback-error-updating-image/60287/5 "2022-01-21T13:05:21Z")
Hi,
Thanks for the reply. I make it correct. Now there are no errors. But still, the image is not showing.
Thanks