[Clojure][Scala] Converting an ndarray to a BufferedImage is really slow

[Chouffe]

When calling the to-image function from the clojure package which interops with the Scala Image/toImage, it is really slow to create the BufferedImage. Waiting for 4-5 seconds on a 1024x576px image ("Pug_cookie.jpg").

[mxnet-label-bot]

Hey, this is the MXNet Label Bot.
Thank you for submitting the issue! I will try and suggest some labels so that the appropriate MXNet community members can help resolve it.
Here are my recommended labels: Scala

[frankfliu]

@mxnet-label-bot add [scala, performance, clojure]

[lanking520]

Yeah it is kind of slow due to the naïve implementation of https://github.com/apache/incubator-mxnet/blob/master/scala-package/core/src/main/scala/org/apache/mxnet/Image.scala#L174-L192. In a sense of converting them pixel by pixel. You can try to use some third-party library to accelerate them

[Chouffe]

Would there be a way to batch (per row or column) the actual RGB conversion?