Tesseract use cmake & Visual studio2019 build show something error.

[吳明恩]

Environment
Tesseract Version:
1.tesseract 4.1.1
2.leptonica-1.76.0 (Nov 3 2020, 10:24:30) [MSC v.1927 LIB Release x64]
3.libtiff 4.1.0
Found AVX2
Found AVX
Found FMA
Found SSE
Platform: Windows 10 64-bit

I use tesseract.exe to OCR jpg to show something error, so i wnat do sothing?

Error message & command:
.\tesseract.exe .\Google.jpg eng
Tesseract Open Source OCR Engine v4.1.1 with Leptonica
Error in pixReadStreamPng: function not present
Error in pixReadStream: png: no pix returned
Error in pixRead: pix not read
Error during processing.

[Zdenko Podobny]

As you see: you build leptonica without any external image library (like png, jpg, tiff), so

tesseract can read only simple image format like bmp, pgm and ppm

Zdenko

ut 3. 11. 2020 o 9:41 吳明恩 <smar...@gmail.com> napísal(a):

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[吳明恩]

Ok, I read bmp image to get result and show something errors, but i can got image string.  

Error message & command :

 .\tesseract.exe .\test.bmp eng

Tesseract Open Source OCR Engine v4.1.1 with Leptonica

Warning: Invalid resolution 0 dpi. Using 70 instead.

Estimating resolution as 284

Error in pixWriteMemPng: function not present 

And, I have a question how can i do build leptonica with  any external image library to can read jpg image?

吳明恩於 2020年11月3日星期二 UTC+8下午4時41分59秒寫道：

[Zdenko Podobny]

You can ignore that message. Some internal functions use zlib, png and tiff but have no effect on OCR.

Your question (regarding leptonica and image types) indicates you are not familiar with building sw from source. In such case use tesseract installer from Mannheim University

Zdenko

ut 3. 11. 2020 o 11:57 吳明恩 <smar...@gmail.com> napísal(a):

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[吳明恩]

Got it, if i use "tesseract installer from Mannheim University"  to can build to  read image for c++, i can't see library & h  file & c file for install script with teessract-ocr. 

吳明恩於 2020年11月3日星期二 UTC+8下午4時41分59秒寫道：