YUV to RGB conversion in OV7620

Hello,

  I am deveolping a VHDL code to get a image from a OV7620 camera. Until
now I have managed to get YUV image in a binary file. When I display that
image the Y component is correct (monochrome image) but the problem is in U
and V components.

  The whole image is all magenta because there isn't green component. I am
using CCIR 601 YCbCr color space with formula:

  R = 1.164(Y – 16) + 1.596(Cr – 128)
  G = 1.164(Y – 16) – 0.813(Cr – 128) – 0.391(Cb – 128)
  B = 1.164(Y – 16) + 2.018(Cb – 128)

  Registers setup are in default mode except for QVGA mode (bit 5 register
14) and CCIR 601 YCrCb (bit 7:6 register 67).

  Thanks.

	   
					
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In article <49ednRDxfI-hAmDRnZ2dnUVZ_tmdnZ2d@giganews.com>, 
jvpiera@n_o_s_p_a_m.yahoo.es says...
> 
> Hello,
> 
>   I am deveolping a VHDL code to get a image from a OV7620 camera. Until
> now I have managed to get YUV image in a binary file. When I display that
> image the Y component is correct (monochrome image) but the problem is in U
> and V components.

Make sure you are getting U and V correctly some devices habe a bit
in one of the registers to determine if the first clock edge is U or V.

Does that model of sensor support a test colour bars output mode.
If so use it to set up your colour decode circuit.
 
>   The whole image is all magenta because there isn't green component. I am
> using CCIR 601 YCbCr color space with formula:

Your data stream could be swapped because you are clocking out of phase.

>   R = 1.164(Y &#4294967295;? 16) + 1.596(Cr &#4294967295;? 128)
>   G = 1.164(Y &#4294967295;? 16) &#4294967295;? 0.813(Cr &#4294967295;? 128) &#4294967295;? 0.391(Cb &#4294967295;? 128)
>   B = 1.164(Y &#4294967295;? 16) + 2.018(Cb &#4294967295;? 128)
> 
>   Registers setup are in default mode except for QVGA mode (bit 5 register
> 14) and CCIR 601 YCrCb (bit 7:6 register 67).
> 
>   Thanks.
> 
> 	   
> 					
> ---------------------------------------		
> Posted through http://www.EmbeddedRelated.com



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