AM62A7: Straight lines look wobbly

li li

Prodigy 30 points

Part Number: AM62A7

Tool/software:

I am using the MATLAB script for correcting an LDC image.

Lens distortion correction looks good in the first place, but straight lines look wobbly.

How to improve this issue？

3 months ago

0 Jianzhong Xu 2 months ago

TI__Guru 58975 points

Hello,

Can you share the LDC configuration?

Thank you.

Jianzhong

0 li li 2 months ago in reply to Jianzhong Xu

Prodigy 30 points

Hi Jianzhong

Below is the script and settings I used

s = 1.15;
m = 4;
pitch_in_mm = 0.0021;
f_in_mm = 4;
W = 3840;
H = 2160;
hc = W/2;
vc = H/2;
Wmesh = ceil(W / 2^m) * 2^m;
Hmesh = ceil(H / 2^m) * 2^m;
gen_lut("spec_file.txt", pitch_in_mm, f_in_mm, Wmesh, Hmesh, hc, vc, s, m);

function [] = gen_lut(spec_file, pitch_in_mm,f_in_mm, W, H, hc, vc,s ,m)
f = f_in_mm/pitch_in_mm ; 
[h_p , v_p] = meshgrid( 0:W, 0:H);
[h_d,v_d] = xyz2distorted(h_p,v_p, f/s, hc, vc,spec_file, pitch_in_mm);
h_delta = round((h_d-h_p) * 8);
v_delta = round((v_d-v_p) * 8);
mh = h_delta(1:2^m:end, 1:2^m:end)';
mv = v_delta(1:2^m:end, 1:2^m:end)';
dlmwrite('mesh.txt', [mh(:), mv(:)],  'delimiter', ' ');
end

function [h_d, v_d] = xyz2distorted(x, y, z, hc, vc, spec_file, pitch_in_mm)
[phi, r] = cart2pol(x-hc, y-vc);
theta = atan2(r, z);
lut = read_spec(spec_file, pitch_in_mm);
r = interp1(lut(:,1), lut(:,2), theta);
[h_d, v_d] = pol2cart(phi, r);
h_d = h_d + hc;
v_d = v_d + vc;
end

function lut = read_spec(spec_file, pitch_in_mm)
lut0 = dlmread(spec_file);
theta = lut0(:,1)/180*pi;
lut = [theta, lut0(:,2)/pitch_in_mm];
end

Fullscreen 7457.spec_file.txt Download

0.00 	0.00 
0.80 	0.06 
1.60 	0.11 
2.41 	0.17 
3.21 	0.22 
4.01 	0.28 
4.81 	0.34 
5.62 	0.39 
6.42 	0.45 
7.22 	0.51 
8.02 	0.56 
8.83 	0.62 
9.63 	0.68 
10.43 	0.73 
11.23 	0.79 
12.03 	0.85 
12.84 	0.91 
13.64 	0.97 
14.44 	1.03 
15.24 	1.09 
16.05 	1.15 
16.85 	1.21 
17.65 	1.27 
18.45 	1.33 
19.25 	1.39 
20.06 	1.46 
20.86 	1.52 
21.66 	1.58 
22.46 	1.65 
23.27 	1.72 
24.07 	1.78 
24.87 	1.85 
25.67 	1.92 
26.48 	1.99 
27.28 	2.06 
28.08 	2.13 
28.88 	2.20 
29.68 	2.27 
30.49 	2.35 
31.29 	2.42 
32.09 	2.50 
32.89 	2.58 
33.70 	2.66 
34.50 	2.74 
35.30 	2.82 
36.10 	2.91 
36.91 	3.00 
37.71 	3.08 
38.51 	3.17 
39.31 	3.27 
40.11 	3.36 
40.92 	3.46 
41.72 	3.56 
42.52 	3.66 
43.32 	3.76 
44.13 	3.87 
44.93 	3.98 
45.73 	4.09 
46.53 	4.21 
47.34 	4.33 
48.14 	4.45 
48.94 	4.58 
49.74 	4.71 
50.54 	4.85 
51.35 	4.99 
52.15 	5.13 
52.95 	5.28 
53.75 	5.44 
54.56 	5.60 
55.36 	5.77 
56.16 	5.95 
56.96 	6.13 
57.76 	6.33 
58.57 	6.53 
59.37 	6.74 
60.17 	6.96 
60.97 	7.19 
61.78 	7.43 
62.58 	7.69 
63.38 	7.96 
64.18 	8.25 
64.99 	8.55 
65.79 	8.87 
66.59 	9.21 
67.39 	9.58 
68.19 	9.97 
69.00 	10.39 
69.80 	10.84 
70.60 	11.33 
71.40 	11.86 
72.21 	12.43 
73.01 	13.05 
73.81 	13.74 
74.61 	14.49 
75.42 	15.33 
76.22 	16.26 
77.02 	17.31 
77.82 	18.48 
78.62 	19.83 
79.43 	21.37 
80.23 	23.16

7457.mesh.txt

Fullscreen ar0823_mesh_ldc_dcc.xml Download

<?xml version="1.0" encoding="utf-8"?>
<cfg_ldc_xml xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns:xsd="http://www.w3.org/2001/xmlschema">
  <!--this is a comment-->
    <dcc_name>cfg_ldc</dcc_name>
    <dcc_header>
        <camera_module_id>     823 </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>
        <ldc_yint_typ type="uint16"> </ldc_yint_typ>
        <ldc_regmode_en type="uint16"> </ldc_regmode_en>
        <ldc_meshtable_m type="uint16"> </ldc_meshtable_m>
        <ldc_mesh_frsz_w type="uint16"> </ldc_mesh_frsz_w>
        <ldc_mesh_frsz_h type="uint16"> </ldc_mesh_frsz_h>
        <ldc_compute_frsz_w type="uint16"> </ldc_compute_frsz_w>
        <ldc_compute_frsz_h type="uint16"> </ldc_compute_frsz_h>
        <ldc_initx type="uint16"> </ldc_initx>
        <ldc_inity type="uint16"> </ldc_inity>
        <ldc_input_frsz_w type="uint16"> </ldc_input_frsz_w>
        <ldc_input_frsz_h type="uint16"> </ldc_input_frsz_h>
        <ldc_obw type="uint16"> </ldc_obw>
        <ldc_obh type="uint16"> </ldc_obh>
        <ldc_pixpad type="uint16"> </ldc_pixpad>
        <ldc_a type="int16"> </ldc_a>
        <ldc_b type="int16"> </ldc_b>
        <ldc_c type="int16"> </ldc_c>
        <ldc_d type="int16"> </ldc_d>
        <ldc_e type="int16"> </ldc_e>
        <ldc_f type="int16"> </ldc_f>
        <ldc_g type="int16"> </ldc_g>
        <ldc_h type="int16"> </ldc_h>
        <ldc_sf_width type="uint16[3]"> </ldc_sf_width>
        <ldc_sf_height type="uint16[3]"> </ldc_sf_height>
        <ldc_sf_en  type="uint16[3][3]"> </ldc_sf_en>
        <ldc_sf_obw type="uint16[3][3]"> </ldc_sf_obw>
        <ldc_sf_obh type="uint16[3][3]"> </ldc_sf_obh>
        <ldc_sf_pad type="uint16[3][3]"> </ldc_sf_pad>
        <ldc_ylut_en type="uint16"> </ldc_ylut_en>
        <ldc_yin_bitdpth type="uint16"> </ldc_yin_bitdpth>
        <ldc_yout_bitdpth type="uint16"> </ldc_yout_bitdpth>
        <ldc_clut_en type="uint16"> </ldc_clut_en>
        <ldc_cin_bitdpth type="uint16"> </ldc_cin_bitdpth>
        <ldc_cout_bitdpth type="uint16"> </ldc_cout_bitdpth>
        <ldc_y_lut type="uint16[513]"> </ldc_y_lut>
        <ldc_c_lut type="uint16[513]"> </ldc_c_lut>
            <mesh_table_pitch_in_bytes type="uint32"> </mesh_table_pitch_in_bytes>
            <mesh_table_size type="uint32"> </mesh_table_size>
            <mesh_lut type="uint16*"> </mesh_lut>
            <chroma_ctl_en type="uint16"> </chroma_ctl_en>
            <chroma_ctl_format type="uint16"> </chroma_ctl_format>
      </cfg_ldc_vars>
    </typedef>
<!--=======================================================================-->
    <use_case val="65535">
    <n-space>
      <region0 class="0">
        <exposure val="1" min="0" max="2000000">  </exposure>
        <gain val="0" min="0" max="100000">  </gain>
      </region0>
    </n-space>

    <parameter_package>
      <ldc_dcc type="cfg_ldc_vars">
      {
          1     // LDC_CTRL              LDC_EN               LDC Enable, 0: Disable,  1: Enable
          1     // LDC_CTRL              LDMAPEN              LD Mapping enable, 0: disable, 1: enable
          4     // LDC_CTRL              DATAMODE             Input data mode, 0: UYVY,  1: Y only, 2: YUV420SP, 3: UV only, 4: YUV422SP, 5: Y1+Y2, 6: Y1 + Y2Y3
          0     // LDC_CTRL              OP_DATAMODE          Output data mode, 0: keep UYVY; 1: convert to 420
          2     // LDC_CTRL              IP_DFMT              Input pixel format, 0: 8b,  1: 12b packed, 2: 12b unpacked
          1     // LDC_CTRL              PWARPEN              0: Disable perspective warp. 1: Enable perspective warp
          1     // LDC_CFG               YINT_TYP             Interpolation type for Y data.  0: Bicubic,  1: Bilinear
          0     // LDC_CFG               REGMODE_EN           Region mode, 0: disable, 1: enable
          4     // LDC_MESHTABLE_CFG     M                    Mesh table subsampling factor (0-7)
          3840     // LDC_MESH_FRSZ         W                    Mesh frame width (0-8192)
          2160     // LDC_MESH_FRSZ         H                    Mesh frame height (0-8192)
          3840     // LDC_COMPUTE_FRSZ      W                    Compute width (0-8192)
          2160     // LDC_COMPUTE_FRSZ      H                    Compute height (0-8192)
          0     // LDC_INITXY            INITX                Output starting horizontal coordinate (0-8192)
          0     // LDC_INITXY            INITY                Output starting vertical coordinate (0-8192)
          3840     // LDC_INPUT_FRSZ        W                    Input frame width
          2160     // LDC_INPUT_FRSZ        H                    Input frame height
          16     // LDC_BLOCK_SIZE        OBW                  Output block width (0-255)
          16     // LDC_BLOCK_SIZE        OBH                  Output block height (0-255)
          1     // LDC_BLOCK_SIZE        PIXPAD               Pixel pad (0-15)
          4096     // LDC_AB                A                    Affine Transform warp, A S16Q12
          0     // LDC_AB                B                    Affine Transform warp, B S16Q12
          0     // LDC_CD                C                    Affine Transform warp, C S16Q3
          0     // LDC_CD                D                    Affine Transform warp, D S16Q12
          4096     // LDC_EF                E                    Affine Transform warp, E S16Q12
          0     // LDC_EF                F                    Affine Transform warp, F S16Q3
          0     // LDC_GH                G                    Affine Transform warp, G S16Q23
          0     // LDC_GH                H                    Affine Transform warp, H S16Q23
          {0, 0, 0}                             //ldc_sf_width [3]
          {0, 0, 0}                             //ldc_sf_height[3]
          {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}     //ldc_sf_en [3][3]
          {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}     //ldc_sf_obw[3][3]
          {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}     //ldc_sf_obh[3][3]
          {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}}     //ldc_sf_pad[3][3]

          0     // LDC_DUALOUT_CFG       YLUT_EN              Luma LUT enable (0-1)
          8     // LDC_DUALOUT_CFG       YIN_BITDPTH          Luma input bit depth (8-12)
          8     // LDC_DUALOUT_CFG       YOUT_BITDPTH         Luma output bit depth (8-12)
          0     // LDC_DUALOUT_CFG       CLUT_EN              Chroma LUT enable (0-1)
          8     // LDC_DUALOUT_CFG       CIN_BITDPTH          Chroma input bit depth (8-12)
          8     // LDC_DUALOUT_CFG       COUT_BITDPTH         Chroma output bit depth (8-12)

          { //y_lut
              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
          }
          { //c_lut
              0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0
          }
          
          976, //mesh_table_pitch_in_bytes
          66368, //mesh_table_size
          { //mesh_lut
              #include "ar0823_mesh_lut.txt"
          }
          1  // LDC_CTRL              CH_CHANCTRL_EN       Chroma control enable, 0: disable, 1: enable
          0  // LDC_CTRL              CH_IP_DFMT           Chroma pixel formats, 0: 8b, 1: 12b packet, 2: 12b unpacked
      }
      </ldc_dcc>
    </parameter_package>
  </use_case>
<!--=====================================================================-->
</cfg_ldc_xml>

0 Jianzhong Xu 2 months ago in reply to li li

TI__Guru 58975 points

Ok. Thanks for sharing. We'll take a look and get back to you as soon as possible.

0 Gang Hua 2 months ago in reply to li li

TI__Guru 59300 points

Hi li,

Your lens spec file does not look good.
Both columns must have higher precision.

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AM62A7: Straight lines look wobbly