Error:
tesseract test.tif output.txt
Tesseract Open Source OCR Engine
check_legal_image_size:Error:Only 1,2,4,5,6,8 bpp are supported:16
Cause: tif image bits/sample value not in 1,2,4,5,6,8 or tif image is transparent with alpha value (Extra Samples: 1<unassoc-alpha>):
tiffinfo test.tif
TIFF Directory at offset 0x7b6 (1974)
Image Width: 145 Image Length: 39
Resolution: 72, 72 (unitless)
Bits/Sample: 8
Compression Scheme: AdobeDeflate
Photometric Interpretation: min-is-black
Extra Samples: 1<unassoc-alpha>
FillOrder: msb-to-lsb
Orientation: row 0 top, col 0 lhs
Samples/Pixel: 2
Rows/Strip: 39
Planar Configuration: single image plane
DocumentName: a.tif
Software: ImageMagick 6.2.8 05/07/12 Q16
Predictor: horizontal differencing 2 (0x2)
Solution: convert tif to acceptable bit sample and remove alpha value:
convert test.tif -background white -alpha remove -flatten -alpha off test.tif
or convert to jpg and reconvert to tif again should remove alpha:
convert test.tif test.jpg
convert test.jpg test.tif