Corrupt image pixels- Creating a mosaic image via 'append'.

[willem.marais]

Hi

I need help to diagnose a problem.

I am trying to create a mosaic image by appending (left to right, and top to bottom) smaller images to each other. The mosaic images' size is usually 8192 by 8192. But when I try to create a mosaic image that is very large, 40068 by 20034, the output image's color values are corrupted.

To illustrate my dilemma, here is an URL of an image which is correct:
ftp://ftp.ssec.wisc.edu/pub/willemm/Ima ... _image.jpg
Here is an URL of a very large image which has corrupt color pixels:
ftp://ftp.ssec.wisc.edu/pub/willemm/Ima ... _image.jpg

The methodology which I used to create the example image is exactly the same. The same input images were used in both examples. I used both ImageMagick versions "6.7.1-2" and "6.5.4-7" to create the images. The methodology that was used to create the images are:

Code: Select all

1. For each row 
2.     For each column
3.         Append image to the column (to make a row) image using: 
                convert -scale $scale_val% $target_image_file $target_image_scaled_file
                convert $col_img_file $target_image_scaled_file +append $col_img_file
2.     Append the new row to previous row image using:
            convert $row_img_file $col_img_file -append $row_img_file
4. Sharpen the image using:
    convert -sigmoidal-contrast 3,50% -modulate 100,125,100 -gamma 1.1 -unsharp 0 -quality 90 $row_img_file $out_file

Thank you
Regards
Willem

[willem.marais]

I solved the problem. The blank images that were added to the colored images were 1-bit level images. 'convert' automatically reduces the colormap of an empty image, I did not take it under consideration.

Regards
Willem