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pytesseract does not extract numbers from image

I am trying to extract numbers from an image using pytesseract but it does not return any text. Here is my code.
from PIL import Image
import pytesseract
im = Image.open('time.png')
custom_oem_psm_config = r'--oem 3 --psm 11 -c tessedit_char_whitelist="0123456789"'# -c preserve_interword_spaces=0'
text= pytesseract.pytesseract.image_to_string(im, config=custom_oem_psm_config)
print(text)
Here is my image
Here is the output

Pyteserract is not able to extract from all images.
It is mostly able to extract text which is similar to normal fonts we use on Microsoft word, notepad, etc.

How to read digits from an image using pytesseract

I'm trying to read the digits from this image:
Using pytesseract with these settings:
custom_config = r'--oem 3 --psm 6'
pytesseract.image_to_string(img, config=custom_config)
This is the output:
((E ST7 [71aT6T2 ] THETOGOG5 15 [8)

Whitelisting only integers, as well as changing your psm provides much better results. You also need to remove carriage returns, and white space. Below is code that does that.
import pytesseract
import re
from PIL import Image
#Open image
im = Image.open("numbers.png")
#Define configuration that only whitelists number characters
custom_config = r'--oem 3 --psm 11 -c tessedit_char_whitelist=0123456789'
#Find the numbers in the image
numbers_string = pytesseract.image_to_string(im, config=custom_config)
#Remove all non-number characters
numbers_int = re.sub(r'[a-z\n]', '', numbers_string.lower())
#print the output
print(numbers_int)
The result of the code on your image is: '31477423353'
Unfortunately, a few numbers are still missing. I tried some experimentation, and downloaded your image and erased the grid.
After removing the grid and executing the code again, pytesseract produces a perfect result: '314774628300558'
So you might try to think about how you can remove the grid programmatically. There are alternatives to pytesseract, but regardless you will get better output with the text isolated in the image.

tesseract image to only digits/numbers

Yes I know there is a lot of question for this subject but I can't find a solution.
I use python 3.8, tesseract v5.0
In this web site , there is a captcha image
https://medeczane.sgk.gov.tr/eczane/SayiUretenImageYeniServlet
(it changes everytick)
I download an image to try as example.jpeg
I try to change for example,
config="digits" ,config="tessedit_char_whitelist=0123456789"
then I try what I find in web. example.jpy is 448301.
I want image to digit numbers and integer type. How can I do that?
numbers = 4 ON\n\x0c
import pytesseract
from PIL import Image
pytesseract.pytesseract.tesseract_cmd = r"C:\Program Files\Tesseract-OCR\tesseract.exe"
numbers=pytesseract.image_to_string(Image.open('example.jpg'),config="digits")

Tesseract - digit regonition with many errors

I want to be able to recognize digits from images. So I have been playing around with tesseract and python. I looked into how to prepare the image and tried running tesseract on it and I must say I am pretty disappointed by how badly my digits are recognized. I have tried to prepare my images with OpenCV and thought I did a pretty good job (see examples below) but tesseract has a lot of errors when trying to identify my images. Am I expecting too much here? But when I look at these example images I think that tesseract should easily be able to identify these digits without any problems. I am wondering if the accuracy is not there yet or if somehow my configuration is not optimal. Any help or direction would be gladly appreciated.
Things I tried to improve the digit recognition: (nothing seemed to improved the results significantly)
limit characters: config = "--psm 13 --oem 3 -c tessedit_char_whitelist=0123456789"
Upscale images
add a white border around the image to give the letters more space, as I have read that this improves the recognition process
Threshold image to only have black and white pixels
Examples:
Image 1:
Tesseract recognized: 72
Image 2:
Tesseract recognized: 0
EDIT:
Image 3:
https://ibb.co/1qVtRYL
Tesseract recognized: 1723

I'm not sure what's going wrong for you. I downloaded those images and tesseract interprets them just fine for me. What version of tesseract are you using (I'm using 5.0)?
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import pytesseract
import cv2
import numpy as np
from PIL import Image
# set path
pytesseract.pytesseract.tesseract_cmd = r'C:\\Users\\ichu\\AppData\\Local\\Programs\\Tesseract-OCR\\tesseract.exe';
# load images
first = cv2.imread("first_text.png");
second = cv2.imread("second_text.png");
images = [first, second];
# convert to pillow
pimgs = [];
for img in images:
rgb = cv2.cvtColor(img, cv2.COLOR_BGR2RGB);
pimgs.append(Image.fromarray(rgb));
# do text
for img in pimgs:
text = pytesseract.image_to_string(img, config='--psm 10 --oem 3 -c tessedit_char_whitelist=0123456789');
print(text[:-2]); # drops newline + end char

Empty string with Tesseract

I'm trying to read different cropped images from a big file and I manage to read most of them but there are some of them which return an empty string when I try to read them with tesseract.
The code is just this line:
pytesseract.image_to_string(cv2.imread("img.png"), lang="eng")
Is there anything I can try to be able to read these kind of images?
Thanks in advance
Edit:

Thresholding the image before passing it to pytesseract increases the accuracy.
import cv2
import numpy as np
# Grayscale image
img = Image.open('num.png').convert('L')
ret,img = cv2.threshold(np.array(img), 125, 255, cv2.THRESH_BINARY)
# Older versions of pytesseract need a pillow image
# Convert back if needed
img = Image.fromarray(img.astype(np.uint8))
print(pytesseract.image_to_string(img))
This printed out
5.78 / C02
Edit:
Doing just thresholding on the second image returns 11.1. Another step that can help is to set the page segmentation mode to "Treat the image as a single text line." with the config --psm 7. Doing this on the second image returns 11.1 "202 ', with the quotation marks coming from the partial text at the top. To ignore those, you can also set what characters to search for with a whitelist by the config -c tessedit_char_whitelist=0123456789.%. Everything together:
pytesseract.image_to_string(img, config='--psm 7 -c tessedit_char_whitelist=0123456789.%')
This returns 11.1 202. Clearly pytesseract is having a hard time with that percent symbol, which I'm not sure how to improve on that with image processing or config changes.