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TDA3XEVM: What should be the Operating Mode for 14-bit Grayscale video output ?

Part Number: TDA3XEVM


My usecase is:  UC_iss _capture_isp_simcop_display.  My capture source is Leopard Imaging OV10640 Camera connected to CSI2 CAM LI port.
When this usecase is selected, IssM2mIspLink_CreateParams_Init( ) is called to set operatingMode to ISSM2MISP_LINK_OPMODE_12BIT_LINEAR.
What does this operating mode do?
I'll be using this usecase for sensor connected to LI CAM parallel port.  It won't be Leopard Imaging OV10460 Parallel sensor.  It'll be some
other imaging sensor which has 14-bit grayscale video output.  What operating mode should I set?
typedef enum
{
    ISSM2MISP_LINK_OPMODE_12BIT_LINEAR = 0,
    /**< upto 12-bit linear mode of operation */
    ISSM2MISP_LINK_OPMODE_1PASS_WDR = 1,
    /**< Single Pass WDR mode of operation */
    ISSM2MISP_LINK_OPMODE_2PASS_WDR = 2,
    /**< Two Pass WDR mode of operation */
    ISSM2MISP_LINK_OPMODE_2PASS_WDR_LINE_INTERLEAVED = 3,
    /**< Two Pass WDR Line Interleaved mode */
    ISSM2MISP_LINK_OPMODE_12BIT_MONOCHROME = 4,
    /**< 12Bit Mononchroma mode,
         In this mode, ISP reads 12bit data,
            does few processing like DPC/NSF3/Black Level subtraction/GLBCE
            and outputs 8bit monochroma data from resizer */
    ISSM2MISP_LINK_OPMODE_MAXNUM = 5,
    /**< Maximum number of operating modes for this link */
    ISSM2MISP_LINK_OPMODE_FORCE32BITS = 0x7FFFFFFF
    /**< This should be the last value after the max enumeration value.
     *   This is to make sure enum size defaults to 32 bits always regardless
     *   of compiler.
     */
} IssM2mIspLink_OperatingMode;
  • Hi Amer,

    This is just linear processing mode, which just convert bayer to YUV/RGB format..
    Any specific reason why you are using 14bit mode. is there any way to get 12bit output?

    Rgds,
    Brijesh
  • Are you sure that the data format is 14-bt linear and not 14-bit WDR companded?

    14-bit data is not supported by the ISP. You must split it or compand it to 12-bit using one of the supported WDR data flows. Here are the options:

    Option 1 - ISSM2MISP_LINK_OPMODE_2PASS_WDR - You will need to specify decompanding parameters for 14->20 bit. ISP will split it into two frames of 12-bits each, process them separately and merge at the end.

    Option 2 - ISSM2MISP_LINK_OPMODE_1PASS_WDR - You will need to specify a Global Tone Map table to convert 14-bit data into 12-bit data.

  • The image sensor that was selected will be connected to LI Camera Port. It outputs 14-bit video signal.
    What is the best option?

    Option 1:
    Can TI Software process Twelve most significant bits and ignore Two least significant bits. If yes, should I select following:

    In IssCaptureLink_CreateParams_Init( )
    SYSTEM_VIFW_12BIT
    SYSTME_DF_RAW12

    In IssM2mIspLink_CreateParams_Init( )

    ISSM2MISP_LINK_OPMODE_12BIT_MONOCHROME

    Option2:
    Use same image sensor as option 1. Connect it to same port as option 1.
    Is it possible to add 14 bit Monochrome Operating mode? Will TI software work? Or lot of software changes will be required?


    Option 3:
    Modify Image sensor to output 12-bit video signal and connect it to Aptina connector. Because Aptina sensor interface outputs 12-bits to SOC. Set VIFW, DF, and OPMODE as option 1 above.

    Option 4:
    This is a question. Previously, TI supported Leopard Imaging OV10640 on LI CAMERA interface. This is 14 bit parallel interface. What were VIFW, DF, and OPMODE set to?
  • >>Can TI Software process Twelve most significant bits and ignore Two least significant bits
    No. The processing happens on ISP, not in SW. Therefore, we have limited flexibility. You may choose a WDR format and select a LUT which maps 14-bit input to 12-bit output by ignoring the 2 LSBs.

    >>Is it possible to add 14 bit Monochrome Operating mode? Will TI software work?
    The limitation is not in SW but in ISP. Adding 14-bit linear mode is not possible.


    >>Previously, TI supported Leopard Imaging OV10640 on LI CAMERA interface. This is 14 bit parallel interface.
    We were configuring the sensor to output 12-b linaer of 12-bit companded output.
  • >> Are you sure that the data format is 14-bt linear and not 14-bit WDR companded?
    No, I'm not sure. Are you asking if the image sensor I'm planning to connect to LI CAMERA port is WDR? The image sensor document basically says it can be calibrated to improve the instantaneous dynamic range of the Focal Plane Array(FPA).
    Also, since current display technologies don't support more than 256 shades of gray, 14-bit output probably means this is WDR sensor.
    Is this sufficient information to select Operating Mode for ISP or do I need to find out if this is WDR from image sensor manufacturer?

    Does companding apply to ISP? If video is WDR, then ISP with compress and expand it or compand it?

    >> Option 1 - ISSM2MISP_LINK_OPMODE_2PASS_WDR - You will need to specify decompanding parameters for 14->20 bit. ISP will split it into two frames of 12-bits each, process them separately and merge at the end
    Is there any documentation so I can understand how to specify decompanding parameters?

    >> Option 2 - ISSM2MISP_LINK_OPMODE_1PASS_WDR - You will need to specify a Global Tone Map table to convert 14-bit data into 12-bit data.
    Is there any documentation so I can understand how to specify global tone map?

    Regards,

    Amer
  • >>  Are you sure that the data format is 14-bt linear and not 14-bit WDR companded?

    I need to understand the question above.  We're planning to connect image sensor to LI CAMERA port.  Are you asking about the output data format of this image sensor?  Please let me know.

  • Yes, I am asking about the output data format of this image sensor.

  • It's infrared thermal Focal Plane Array(FPA). 640 columns by 480 rows. It's 14-bit Grayscale or Monochrome WDR. There is no companding.

    Regards,

    Amer
  • Linear mode in ISP is supported upto 12-bit only. 14-bit format can be supported but it will have to be treated as WDR data. The operating mode should be 1-Pass WDR. You will need to define a companding LUT from 14 -> 12 bit