I would say check the popular vendors ...

https://www.altera.com/products/intellectual-property/ip/dsp/m-alt-vipsuite.html

https://www.xilinx.com/products/boards-and-kits/board-functions/nav-video-and-image-processing.html

PS- I am not taking sides or marketing and they are expensive ...

It is a trade-off you either take DSP + FPGA or above mentioned .

Remember the software suite needs to have the IPs else it is another story

Kindly have a look at the following details for different FPGA for image processing tasks:

https://www.mathworks.com/videos/vision-processing-fpga-and-asic-hardware-considerations-1504125974287.html

https://www.xilinx.com/products/boards-and-kits/board-functions/nav-video-and-image-processing.html

Without knowing your application it's impossible to make any recommendations. FPGA boards range in price from about 100$ up to several 10,000$. Furthermore, there are huge differences in the design software options. For example, both Xilinx and Altera (now owned by Intel) both offer OpenCL synthesis software and IP-Core libraries, but you need a license to use them (which again costs you some 1,000$ annually).

Some Xilinx Kits include a license voucher giving you updates for one year (see, for example, https://www.xilinx.com/products/boards-and-kits/zcu104.html - I think Altera will have similar kits, but I'm more familiar with Xilinx). The ZCU104 sports a quite powerful FPGA part combined with several ARM cores, the price is very interesting.

However, let me ask one question: why did you decide to use an FPGA? They're no magical problem solvers but require quite some knowledge to work with them efficiently (your question sounds like this will be your first time working with FPGAs). Have you considered using GPUs, e.g, a Jetson board? I think they much easier to get acustomed with than FPGAs.