An image synthesizer for a surround monitoring or display system for a vehicle, the surround monitoring system comprising four cameras (201, 202, 203, 204) for capturing four images including a first camera, a second camera, and a control module, the first camera being configured to capture a first image from a first scene, the second camera being configured to capture a second image from a second scene, the control module being configured to generate a control signal indicating a condition external to the vehicle, wherein the first scene and the second scene partly overlap in an overlapping region of a surveillance area of the vehicle, wherein the four cameras (201, 202, 203, 204) are attached at the four corners of the vehicle so that each part of the surveillance area is covered by two images of the four images, wherein, if a three-dimensional object is present in the overlapping region, the presence of the object is related to the external condition and the control signal indicates a position of the 3D object in the overlapping region, the image synthesizer comprising: - a receiving module for receiving the first image, the second image, and the control signal; - a combining module for combining the first image and the second image in the overlapping region and, dependent on the control signal, to generate a combined image, the combining module being further configured to combine the first image and the second image by blending the first image and the second image in a blending region being part of the overlapping region such that the position of the 3D object is outside blending region, wherein the blending region is moved inside the overlapping area, to perform the blending dependent on the condition external to the vehicle wherein the condition external to the vehicle includes at least one of the following: a driving condition, an environmental condition of the vehicle, a weather condition, a condition of the surface of the ground, speed or position or orientation of the vehicle, and wherein a blending width or a granularity of the blending depends on the external condition. wherein the first scene and the second scene partly overlap in an overlapping region of a surveillance area of the vehicle, wherein the four cameras (201, 202, 203, 204) are attached at the four corners of the vehicle so that each part of the surveillance area is covered by two images of the four images, wherein, if a three-dimensional object is present in the overlapping region, the presence of the object is related to the external condition and the control signal indicates a position of the 3D object in the overlapping region, the image synthesizer comprising: - a receiving module for receiving the first image, the second image, and the control signal; - a combining module for combining the first image and the second image in the overlapping region and, dependent on the control signal, to generate a combined image, the combining module being further configured to combine the first image and the second image by blending the first image and the second image in a blending region being part of the overlapping region such that the position of the 3D object is outside blending region, wherein the blending region is moved inside the overlapping area, to perform the blending dependent on the condition external to the vehicle wherein the condition external to the vehicle includes at least one of the following: a driving condition, an environmental condition of the vehicle, a weather condition, a condition of the surface of the ground, speed or position or orientation of the vehicle, and wherein a blending width or a granularity of the blending depends on the external condition. - a receiving module for receiving the first image, the second image, and the control signal; - a combining module for combining the first image and the second image in the overlapping region and, dependent on the control signal, to generate a combined image, the combining module being further configured to combine the first image and the second image by blending the first image and the second image in a blending region being part of the overlapping region such that the position of the 3D object is outside blending region, wherein the blending region is moved inside the overlapping area, to perform the blending dependent on the condition external to the vehicle wherein the condition external to the vehicle includes at least one of the following: a driving condition, an environmental condition of the vehicle, a weather condition, a condition of the surface of the ground, speed or position or orientation of the vehicle, and wherein a blending width or a granularity of the blending depends on the external condition. to combine the first image and the second image by blending the first image and the second image in a blending region being part of the overlapping region such that the position of the 3D object is outside blending region, wherein the blending region is moved inside the overlapping area, to perform the blending dependent on the condition external to the vehicle wherein the condition external to the vehicle includes at least one of the following: a driving condition, an environmental condition of the vehicle, a weather condition, a condition of the surface of the ground, speed or position or orientation of the vehicle, and wherein a blending width or a granularity of the blending depends on the external condition.