@mksarker1 This is incorrect. The prediction masks should be single-channel PNG images, just like the Training ground truth masks.
Per the instructions on the Task 1 description:
The response data are binary mask images in PNG format, indicating the location of the primary skin lesion within each input lesion image.
Mask images are named using the scheme
<image_id> matches the corresponding lesion image for the mask.
Mask images must have the exact same dimensions as their corresponding lesion image. Mask images are encoded as single-channel (grayscale) 8-bit PNGs (to provide lossless compression), where each pixel is either:
- 0: representing the background of the image, or areas outside the primary lesion
- 255: representing the foreground of the image, or areas inside the primary lesion
As the primary skin lesion is a single contiguous region, mask images should also contain only a single contiguous foreground region, without any disconnected components or holes. The foreground region may be of any size (including the entire image) and may abut the borders of the image.