Each "multiscales" dictionary MUST contain the field "axes", see § 3.1 "axes" metadata. The length of "axes" must be between 2 and 5 and MUST be equal to the dimensionality of the zarr arrays storing the image data (see "datasets:path"). The "axes" MUST contain 2 or 3 entries of "type:space" and MAY contain one additional entry of "type:time" and MAY contain one additional entry of "type:channel" or a null / custom type. The order of the entries MUST correspond to the order of dimensions of the zarr arrays. In addition, the entries MUST be ordered by "type" where the "time" axis must come first (if present), followed by the "channel" or custom axis (if present) and the axes of type "space". If there are three spatial axes where two correspond to the image plane ("yx") and images are stacked along the other (anisotropic) axis ("z"), the spatial axes SHOULD be ordered as "zyx".
Each "multiscales" dictionary MUST contain the field "datasets", which is a list of dictionaries describing the arrays storing the individual resolution levels. Each dictionary in "datasets" MUST contain the field "path", whose value contains the path to the array for this resolution relative to the current zarr group. The "path"s MUST be ordered from largest (i.e. highest resolution) to smallest.
Each "datasets" dictionary MUST have the same number of dimensions and MUST NOT have more than 5 dimensions. The number of dimensions and order MUST correspond to number and order of "axes". Each dictionary in "datasets" MUST contain the field "coordinateTransformations", which contains a list of transformations that map the data coordinates to the physical coordinates (as specified by "axes") for this resolution level. The transformations are defined according to § 3.3 "coordinateTransformations" metadata. The transformation MUST only be of type translation or scale. They MUST contain exactly one scale transformation that specifies the pixel size in physical units or time duration. If scaling information is not available or applicable for one of the axes, the value MUST express the scaling factor between the current resolution and the first resolution for the given axis, defaulting to 1.0 if there is no downsampling along the axis. It MAY contain exactly one translation that specifies the offset from the origin in physical units. If translation is given it MUST be listed after scale to ensure that it is given in physical coordinates. The length of the scale and translation array MUST be the same as the length of "axes". The requirements (only scale and translation, restrictions on order) are in place to provide a simple mapping from data coordinates to physical coordinates while being compatible with the general transformation spec.
Each "multiscales" dictionary MAY contain the field "coordinateTransformations", describing transformations that are applied to all resolution levels in the same manner. The transformations MUST follow the same rules about allowed types, order, etc. as in "datasets:coordinateTransformations" and are applied after them. They can for example be used to specify the scale for a dimension that is the same for all resolutions.
Each "multiscales" dictionary SHOULD contain the field "name". It SHOULD contain the field "version", which indicates the version of the multiscale metadata of this image (current version is 0.4).
Each "multiscales" dictionary SHOULD contain the field "type", which gives the type of downscaling method used to generate the multiscale image pyramid. It SHOULD contain the field "metadata", which contains a dictionary with additional information about the downscaling method.
Each "multiscales" dictionary MUST contain the field "axes", see § 3.1 "axes" metadata. The length of "axes" must be between 2 and 5 and MUST be equal to the dimensionality of the zarr arrays storing the image data (see "datasets:path"). The "axes" MUST contain 2 or 3 entries of "type:space" and MAY contain one additional entry of "type:time" and MAY contain one additional entry of "type:channel" or a null / custom type. The order of the entries MUST correspond to the order of dimensions of the zarr arrays. In addition, the entries MUST be ordered by "type" where the "time" axis must come first (if present), followed by the "channel" or custom axis (if present) and the axes of type "space". If there are three spatial axes where two correspond to the image plane ("yx") and images are stacked along the other (anisotropic) axis ("z"), the spatial axes SHOULD be ordered as "zyx".
Each "multiscales" dictionary MUST contain the field "datasets", which is a list of dictionaries describing the arrays storing the individual resolution levels. Each dictionary in "datasets" MUST contain the field "path", whose value contains the path to the array for this resolution relative to the current zarr group. The "path"s MUST be ordered from largest (i.e. highest resolution) to smallest.
Each "datasets" dictionary MUST have the same number of dimensions and MUST NOT have more than 5 dimensions. The number of dimensions and order MUST correspond to number and order of "axes". Each dictionary in "datasets" MUST contain the field "coordinateTransformations", which contains a list of transformations that map the data coordinates to the physical coordinates (as specified by "axes") for this resolution level. The transformations are defined according to § 3.3 "coordinateTransformations" metadata. The transformation MUST only be of type translation or scale. They MUST contain exactly one scale transformation that specifies the pixel size in physical units or time duration. If scaling information is not available or applicable for one of the axes, the value MUST express the scaling factor between the current resolution and the first resolution for the given axis, defaulting to 1.0 if there is no downsampling along the axis. It MAY contain exactly one translation that specifies the offset from the origin in physical units. If translation is given it MUST be listed after scale to ensure that it is given in physical coordinates. The length of the scale and translation array MUST be the same as the length of "axes". The requirements (only scale and translation, restrictions on order) are in place to provide a simple mapping from data coordinates to physical coordinates while being compatible with the general transformation spec.
Each "multiscales" dictionary MAY contain the field "coordinateTransformations", describing transformations that are applied to all resolution levels in the same manner. The transformations MUST follow the same rules about allowed types, order, etc. as in "datasets:coordinateTransformations" and are applied after them. They can for example be used to specify the scale for a dimension that is the same for all resolutions.
Each "multiscales" dictionary SHOULD contain the field "name". It SHOULD contain the field "version", which indicates the version of the multiscale metadata of this image (current version is 0.4).
Each "multiscales" dictionary SHOULD contain the field "type", which gives the type of downscaling method used to generate the multiscale image pyramid. It SHOULD contain the field "metadata", which contains a dictionary with additional information about the downscaling method.
https://ngff.openmicroscopy.org/0.4/index.html#multiscale-md