Convert a raster to GeoJSON polygons in PostGIS

I'm trying to convert a raster to a polygon and export it from PostGIS as GeoJSON. Specifically I want each pixel to be a polygon with associated the raster value.

PostGIS seems to have a few different functions for converting rasters to polygons, I'm using the ST_PixelAsPolygons function because I want each pixel to be represented as its own polygon.

Example:

SELECT ST_PixelAsPolygon(rast) FROM tbl;

However this returns a set of records for each raster and I can't easily convert this to GeoJSON.

Does anyone know of a simple way to do this?