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DLP4500: Residual light when projecting a black image over HDMI

Part Number: DLP4500
Other Parts Discussed in Thread: TEST

Hi, 

I was wondering if anyone would be able to help me with an issue that I'm having. I'm currently using Matlab to generate some patterned masks, which are then sent over HDMI to the Wintech PRO4500. The issue that I'm having is that even when projecting a black screen (i.e black image in Matlab), there is a significant amount of light still coming out of the projector. Is there a way to fix this (or know why this happens), or a better way to stream images from Matlab to the PRO4500 that negates this issue? 

Any help would be greatly appreciated. 

Kind regards,

Callum 

  • Hello Callum,

    Can you try displaying a black image with internal display mode of the controller (like solid field or TPG) and let us know if you still see residual light in that case?

    Regards,

    Mayank

  • Hi Mayank, 

    I'm actually running into some connectivity issues with the PRO4500, as I cannot seem to connect to it over USB, hence why I was trying to do some testing with HDMI initially. We have two units and they both don't seem to show up in the device manager, and won't connect using the GUI. I don't think its a firmware issue as its unlikely that the firmware is corrupted on two units. I've checked that there aren't any jumpers on J18 and J30. The green light however is blinking on the top of the unit and am using the latest version of the GUI and windows 10. We have a PRO6500 in the lab that I routinely connect to with no issues, so I'm not sure why there is an issue with the PRO4500. 

    Not sure if you have any recommendations with regards to getting the USB working? Once I can connect to it over USB, should be able to test to see if there is any residual backlight with a solid black image. 

    Any help would be greatly appreciated! 

    Kind regards,

    Callum 

  • Hi Callum,

    Thank you for letting us know about this update. We will look further into this and have a response by next week.

    Thank you,

    Chris

  • Hi Chris, 

    I've managed to fix the USB connection issue and project the horizontal line test pattern (image attached). There seems to be no background light emitted when showing the test pattern, however, when I send a crosshair pattern over HDMI from Matlab, there is a lot of background light where it should be black (image attached). 

    internal test pattern

    hdmi pattern

  • Hi Callum,

    We tried to reproduce it on our side but we don't see any backlight. Can you please try generating the cross hair pattern bmp image with resolution 912x1140 and save it in the flash using the firmware build tab and project it using the flash image source in video mode tab.  

    Can you please save the solution and share the .ini file to see if there is any discrepancies.

    Regards,

    Akhil

  • Hi Akhil, 

    Generating and uploading the cross-hair seems to be fine (image attached), with no visible backlight.

     image from internal flash

    However, I'm still getting the residual backlight from the projector when using it over HDMI, as shown below. 

    This is what i'm projecting over HDMI from Matlab. i.e white cross hair 'value = 1' with black background '0'.

    Here is my ini file as well. 

    APPCONFIG.VERSION.SUBMINOR 0x0 ;
    APPCONFIG.VERSION.MINOR 0x0 ;
    APPCONFIG.VERSION.MAJOR 0x3 ;
    DEFAULT.FIRMWARE_TAG 0x0 ;
    DEFAULT.AUTOSTART 0x0 ;
    DEFAULT.DISPMODE 0x0 ;
    DEFAULT.SHORT_FLIP 0x0 ;
    DEFAULT.LONG_FLIP 0x0 ;
    DEFAULT.TRIG_OUT_1.POL 0x0 ;
    DEFAULT.TRIG_OUT_1.RDELAY 0x0 ;
    DEFAULT.TRIG_OUT_1.FDELAY 0x0 ;
    DEFAULT.TRIG_OUT_2.POL 0x0 ;
    DEFAULT.TRIG_OUT_2.WIDTH 0x0 ;
    DEFAULT.TRIG_IN_1.DELAY 0x1 ;
    DEFAULT.TRIG_IN_2.POL 0x0 ;
    DEFAULT.RED_STROBE.RDELAY 0x0 ;
    DEFAULT.RED_STROBE.FDELAY 0x0 ;
    DEFAULT.GRN_STROBE.RDELAY 0x0 ;
    DEFAULT.GRN_STROBE.FDELAY 0x0 ;
    DEFAULT.BLU_STROBE.RDELAY 0x0 ;
    DEFAULT.BLU_STROBE.FDELAY 0x0 ;
    DEFAULT.INVERTDATA 0x0 ;
    DEFAULT.TESTPATTERN 0x0 ;
    DEFAULT.LEDCURRENT_RED 0x97 ;
    DEFAULT.LEDCURRENT_GRN 0x78 ;
    DEFAULT.LEDCURRENT_BLU 0x7d ;
    DEFAULT.PATTERNCONFIG.PAT_EXPOSURE 0x7a120 ;
    DEFAULT.PATTERNCONFIG.PAT_PERIOD 0x7a120 ;
    DEFAULT.PATTERNCONFIG.PAT_MODE 0x3 ;
    DEFAULT.PATTERNCONFIG.TRIG_MODE 0x1 ;
    DEFAULT.PATTERNCONFIG.PAT_REPEAT 0x1 ;
    DEFAULT.PATTERNCONFIG.NUM_SPLASH 0x0 ;
    DEFAULT.SPLASHLUT 0x1 ;
    DEFAULT.PATTERNCONFIG.NUM_LUT_ENTRIES 0x2 ;
    DEFAULT.PATTERNCONFIG.NUM_PATTERNS 0x2 ;
    DEFAULT.SEQPATLUT 0x61800 0x22804 0x24808 ;
    DEFAULT.LED_ENABLE_MAN_MODE 0x0 ;
    DEFAULT.MAN_ENABLE_RED_LED 0x0 ;
    DEFAULT.MAN_ENABLE_GRN_LED 0x0 ;
    DEFAULT.MAN_ENABLE_BLU_LED 0x0 ;
    DEFAULT.PORTCONFIG.PORT 0x0 ;
    DEFAULT.PORTCONFIG.BPP 0x0 ;
    DEFAULT.PORTCONFIG.PIX_FMT 0x0 ;
    DEFAULT.PORTCONFIG.PORT_CLK 0x0 ;
    DEFAULT.PORTCONFIG.ABC_MUX 0x4 ;
    DEFAULT.PORTCONFIG.PIX_MODE 0x1 ;
    DEFAULT.PORTCONFIG.SWAP_POL 0x1 ;
    DEFAULT.PORTCONFIG.FLD_SEL 0x0 ;
    PERIPHERALS.I2CADDRESS[0] 0x34 ;
    PERIPHERALS.I2CADDRESS[1] 0x3a ;
    PERIPHERALS.I2CBUSYGPIO_ENABLE 0x0 ;
    PERIPHERALS.I2CBUSYGPIO_SELECT 0x0 ;
    DATAPATH.SPLASHSTARTUPTIMEOUT 0x1388 ;
    DATAPATH.SPLASHATSTARTUPENABLE 0x1 ;
    MACHINE_DATA.COLORPROFILE_0_BRILLIANTCOLORLOOK 0x0 ;
    

    I don't think its a firmware issue as we recently purchased two PRO4500 and they both have this same issue. 

    Thanks for all the help! 

    Kind regards,

    Callum 

  • Hi Callum

    Thank you for the updated information. Our team will look into this and get back to you in a few days.

    Thank you,

    Chris

  • Hi Callum,

    The controller seems to be projecting the RGB input data properly. Please validate the HDMI output data that you are transmitting.

    Can you please try displaying a solid black pattern using the matlab HDMI generation and confirm whether the residual still exists. 

    If so I request you verify whether the RGB data corresping to black is zero or not. PC HDMI Driver often manipulates this and does not send zero exaclty for the black. Hence the discrepancy.

    Regards,

    Akhil