Fails to recognize short codes

[Daniele]

Hi,

using a 3rd part software (NormCap) that internally uses tesseract, I tried to recognize this code:

The result was a mess, no letter are recognized.

Also the result using CLI and tesseract was a mess. I can't undestand with params I could use to get right output.

Can someone help me?

Thanks!

[nguyen ngoc hai]

I think you may need to do some preprocessing for your image before send it to tesseract:

For example: 
```

---------------------- ----------- gray_image -----------

---------------------- ----------- blur1 -----------

---------------------- ----------- otsu -----------

---------------------- ----------- erosion -----------

---------------------- ----------- blur -----------

---------------------- 

SINGLE_LINE 

6KDYT?79M" 

 AUTO 

6KDYT?79M" 

 RAW_LINE 

6KDYT79M 

 SPARSE_TEXT_OSD 

6KDYT?79M" 

 SINGLE_WORD 

6KDYT79M

```
As you can see, 2 PSM modes could give the correct results:

Here is the full code in python:

image_org = cv2.imread("unnamed.png")

height, width = image_org.shape[:2]

# calculate the amount of pixels to crop from the border

x_border = int(width * 0.1)

y_border = int(height * 0.1)

image = image_org[y_border:height-y_border, x_border:width-x_border]

cv2_show("image", image, 600)

gray_image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

cv2_show("gray_image", gray_image, 600)

blur1 = cv2.GaussianBlur(gray_image,(21,21),0)

cv2_show("blur1", blur1, 600)

# global thresholding

ret, otsu = cv2.threshold(blur1,0,255,cv2.THRESH_BINARY_INV+cv2.THRESH_OTSU)

cv2_show("otsu", otsu, 800)

kernel = np.ones((3,3),np.uint8)

erosion = cv2.erode(otsu,kernel,iterations = 1)

cv2_show("erosion", erosion, 800)

blur = cv2.GaussianBlur(erosion,(5,5),0)

cv2_show("blur", blur, 600)

results = get_text(255-blur)

for ret in results:

    print(ret[0][0])

    print(ret[1][0])

Hope it helps.
Regards

Hai

[nguyen ngoc hai]

Forgot to check if the images were properly attached. Here they are:

----------- image ----------- 

 ----------------------
----------- gray_image ----------- 

 ----------------------
----------- blur1 ----------- 

 ----------------------
----------- otsu ----------- 

 ----------------------
----------- erosion ----------- 

 ----------------------
----------- blur ----------- 

 ----------------------
SINGLE_LINE
6KDYT?79M"

AUTO
6KDYT?79M"

RAW_LINE
6KDYT79M

SPARSE_TEXT_OSD
6KDYT?79M"

SINGLE_WORD
6KDYT79M

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Nguyen Ngoc Hai

Phone:  +81 1488 4168  (JP).

skype ID: nguyenngochaibkhn.

[Daniele]

Cool!

Thank you very much!

Daniele