FingerPrint Transferring 4 bit

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Emrah Duatepe
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Posted by Emrah Duatepe: Thu. Nov 14, 2019 - 05:35 AM
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Hi guys, I am going to use fingerprint sensor and the values that I have got are about 34000 and datasheet tell me 

"ImageBuffer serves for image storage and the image format is 256*288 pixels.
When transferring through UART, to quicken speed, only the upper 4 bits of the pixel is transferred (that is 16 grey degrees). And two adjacent pixels of the same row will form a byte before the transferring. When uploaded to PC, the 16-grey-degree image will be extended to 256-grey-degree format. That¡s 8-bit BMP format."

I dont what does it mean excatly.My information about pictures is not good sufficiently.If I put these array in C#,the program gives error.So how can I get arrays in right way,or any person did it? any simple code or an nice information please.Thank you.

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Tools, Compilers and General Programming
Last Edited: Thu. Nov 14, 2019 - 09:28 AM
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Kartman
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Posted by Kartman: Thu. Nov 14, 2019 - 07:22 AM
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There must be a program running on the PC that receives the data and converts it to a BMP file. You've not given us much information to work with.

 

Emrah Duatepe wrote:
If I put these array in C#,the program gives error.
How are supposed to figure this out? What data, into what array with what code and what error? We're not magicians!

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Emrah Duatepe
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Posted by Emrah Duatepe: Thu. Nov 14, 2019 - 10:25 AM
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If I convert the any fingerprint in byte array and place in the code for convert bitmap in C# in this case code works but if I get the array from fingerprint device and put in the C# in same code in this case code doesn't accept the array.

I think this is about this sentence

 

to quicken speed, only the upper 4 bits of the pixel is transferred (that is 16 grey degrees). And two adjacent pixels of the same row will form a byte before the transferring. When uploaded to PC, the 16-grey-degree image will be extended to 256-grey-degree format. That¡s 8-bit BMP format.

 

 

But how can I manage the convert in this shape. Code aim below is  to convert byte array to image from sensor but it doesn't work but If  use any fingerprint picture from google or anywhere convert to byte array and put in this code it is okay.I can get picture again in this case problem is fingerprint device send missing arrays like I explain up.

 

MemoryStream memstr = new MemoryStream(bytesArr);
Image img = Image.FromStream(memstr);

 

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Kartman
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Posted by Kartman: Thu. Nov 14, 2019 - 10:29 AM
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Emrah Duatepe wrote:

When uploaded to PC, the 16-grey-degree image will be extended to 256-grey-degree format. That¡s 8-bit BMP format.

 

 

I'd suggest YOU need to do the conversion. Some simple math will tell you what the actual data is. Your code needs to split each byte into nibbles then multiply by 16 then storage it into a BMP structure. What is a BMP structure? Best be Googling methinks.

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Emrah Duatepe
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Posted by Emrah Duatepe: Thu. Nov 14, 2019 - 10:33 AM
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Okay,thank you I am gonna search it now.

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