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AM62A7: LDC module LUT inquiry

Part Number: AM62A7

Tool/software:

Hi experts

Can setting appropriate LUT in the LDC module achieve a 90 degree rotation of the screen.

for example,Images with a resolution of 1920 * 1280 can be displayed at a resolution of 1280 * 1920 after passing through the LDC module.

  • In addition, does the MSC module have the function of rotating the screen in addition to the zoom function?

  • Hello Qiang,

    Yes, LDC can rotate images by 90 degree, but MSC doesn't do that.

    Regards,

    Jianzhong

  • Hi peng,

    Can setting appropriate LUT in the LDC module achieve a 90 degree rotation of the screen.

    For these in-plane 2D transform, it is easier to use the 2D matrix in LDC (no need to use the LUT).

  • For these in-plane 2D transform, it is easier to use the 2D matrix in LDC (no need to use the LUT)

    Hi Gang

    Does the two-dimensional matrix of LDC you mentioned refer to the parameters in the following figure。

    I have consulted the manual. The first six parameters are affine transform coefficient.

    The last two parameters are perspective warp transform coefficient.

    Is there a more detailed introduction about two-dimensional matrices.

  • Hi Peng,

    Yes, that is the one.

    For 2D affine transform, you only need to use A,B,C,D,E,F.

    It is a simple transform as below (you can ignore z, g, h).

    (h_u, v_u) starts from (0,0) to output image (width-1, height-1).
    Same for (h_afff, v_aff) for input image location.

    You shall be able to find some previous discussion on e2e for this topic.

  • Hi Gang

    I made modifications to the XML file;

    a = 0;b= 4096;c = 0

    d = 4096;e = 0;f = 0

    The image has not changed.

    Is there a problem with setting up where to use it?

  • x3c_mesh_ldc_dcc.xml
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    <?xml version="1.0" encoding="utf-8"?>
    <LDC_ODC xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <!--this is comment-->
    <dcc_name>ldc_odc</dcc_name>
    <dcc_header>
    <camera_module_id> 233</camera_module_id>
    <dcc_descriptor_id> 5</dcc_descriptor_id>
    <algorithm_vendor_id> 1</algorithm_vendor_id>
    <tunning_tool_version> 0</tunning_tool_version>
    </dcc_header>
    <!--=======================================================================-->
    <typedef>
    <cfg_ldc_vars type="struct">
    <ldc_en type="uint16"> </ldc_en>
    <ldc_ldmapen type="uint16"> </ldc_ldmapen>
    <ldc_datamode type="uint16"> </ldc_datamode>
    <ldc_opdatamode type="uint16"> </ldc_opdatamode>
    <ldc_ip_dfmt type="uint16"> </ldc_ip_dfmt>
    <ldc_pwarpen type="uint16"> </ldc_pwarpen>
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    this is an xml file.

  • The image has not changed.

    Hi peng,

    You may try it out in tuning tool first to get the correct parameters.

  • (h_u, v_u) starts from (0,0) to output image (width-1, height-1).
    Same for (h_afff, v_aff) for input image location.

    Hi Gang

    Is the input to LDC on the left side of the formula?
    Normally, it's easier to understand input on the right side

  • Hi peng,

    Is the input to LDC on the left side of the formula?

    It is the normal  y = f(x) notation with x for input and y for output.

  • Hi Gang 

    I asked a question unrelated to this case.

    What is the use of this parameter in ae?

    1586.gsttiovxisp.c

  • What is the coordinate system for affine transformation in the LDC module?Is it shown in the following picture?

  • Hi Peng,

    What is the use of this parameter in ae?

    This is for changing exposure time in steps.

  • I asked a question unrelated to this case.

    BTW, please feel free to open a new thread with proper title for any new questions.
    That is better for tracking.

  • Hi Peng,

    What is the coordinate system for affine transformation in the LDC module?Is it shown in the following picture?

    Yes, that is the right one.
    LDC uses integer pixel counters starting from 0.

  • After rotating clockwise by 90 °, the position relationship should be as shown in the diagram。

    The corresponding affine transformation matrix is 

    At this time, the x-coordinate should be shifted 1280(1920*1280) pixels in the positive direction。The corresponding radiative transformation matrix is .

    But in reality, the affine transformation matrix that can obtain correct results in LDC is .

    What is the reason for this?

  • This one above is definitely wrong as the first output would be in [1280, 1280+1920] and second in [-1279, 0].

  • It looks like you are confused by the range of pixel locations.

    It must be starting from 0 to image width and height for both input and output images.

  • This one above is definitely wrong as the first output would be in [1280, 1280+1920] and second in [-1279, 0].

    Is the first output X?if it is,the first output would be in [1280, 1280+1280] and second in [-1920, 0].

    X = y + 1280;

    Y = -x;

    y in [0,1280],x in [0 1920]

    I don't understand how the two ranges you mentioned were calculated.

  • Y = -x;

    Y is in [-1279, 0] since x is in [0, 1279].

    X = y + 1280;

    X is in [1280+1280, 0] since y is in [0, 1919].

    Is the first output X?

    X, Y are for your input image.

    x is horizontal counter for your output image [0,1279].

    y is vertical counter for your output image [0,1919].